#anisogamy

[religion-is-a-mental-illness]

By: Robert Lynch

Published: April 7, 2023

In my first year of graduate school at Rutgers, I attended a colloquium designed to forge connections between the cultural and biological wings of the anthropology department. It was the early 2000s, and anthropology departments across the country were splitting across disciplinary lines. These lectures would be a last, and ultimately futile, attempt to build interdisciplinary links between these increasingly hostile factions at Rutgers; it was like trying to establish common research goals for the math and art departments.

This time, it was the turn of the biological anthropologists, and the primatologist Ryne Palombit was giving a lecture for which he was uniquely qualified — infanticide in Chacma baboons. Much of the talk was devoted to sex differences in baboon behavior and when it was time for questions the hand of the chair of the department, a cultural anthropologist, shot up and demanded to know “What exactly do you mean by these so-called males and females?” I didn’t know it at the time but looking back I see that this was the beginning of a broad anti-science movement that has enveloped nearly all the social sciences and distorted public understanding of basic biology. The assumption that sex is an arbitrary category is no longer confined to the backwaters of cultural anthropology departments, and the willful ignorance of what sex is has permeated both academia and public discussion of the topic.

Male and female are not capricious categories imposed by scientists on the natural world, but rather refer to fundamental distinctions deeply rooted in evolution. The biological definition of males and females rests on the size of the sex cells, termed gametes, that they produce. Males produce large numbers of small gametes, while females produce fewer, larger ones. In animals, this means that males produce lots of tiny sperm (between 200 and 500 million sperm in humans) while females produce far fewer, but much larger, eggs called ova (women have a lifetime supply of around 400). Whenever scientists discover a new sexually reproducing species, gamete size is what they use to distinguish between the males and the females.

Although this asymmetry in gamete size may not seem that significant, it is. And it leads to a cascade of evolutionary effects that often results in fundamentally different developmental (and even behavioral) trajectories for the two respective sexes. Whether you call the two groups A and B, Big and Little, or Male and Female, this foundational cell-sized difference in gamete size has profound effects on evolution, morphology, and behavior. Sexual reproduction that involves the union of gametes of different sizes is termed anisogamy, and it sets the stage for characteristic, and frequently stereotypical, differences between males and females.

My PhD advisor, the evolutionary biologist Robert Trivers, was at that doomed colloquium at Rutgers. It was Trivers, who four decades earlier as a graduate student at Harvard, laid down the basic evolutionary argument in one of the most cited papers in biology. Throwing down the gauntlet and explaining something that had puzzled biologists since Darwin, he wrote, “What governs the operation of sexual selection is the relative parental investment of the sexes in their offspring.” In a single legendary stroke of insight, which he later described in biblical terms (“the scales fell from my eyes”), he revolutionized the field and provided a broad framework for understanding the emergence of sex differences across all sexually reproducing species.

Because males produce millions of sperm cells quickly and cheaply, the main factor limiting their evolutionary success lies in their ability to attract females. Meanwhile, the primary bottleneck for females, who, in humans, spend an additional nine months carrying the baby, is access to resources. The most successful males, such as Genghis Khan who is likely to have had more than 16 million direct male descendants, can invest relatively little and let the chips fall where they may, while the most successful women are restricted by the length of their pregnancy. Trivers’ genius, however, was in extracting the more general argument from these observations.

By replacing “female” with “the sex that invests more in its offspring,” he made one of the most falsifiable predictions in evolution — the sex that invests more in its offspring will be more selective when choosing a mate while the sex that invests less will compete over access to mates. That insight not only explains the rule, but it also explains the exceptions to it. Because of the initial disparity in investment (i.e., gamete size) females will usually be more selective in choosing mates. However, that trajectory can be reversed under certain conditions, and sometimes the male of a species will invest more in offspring and so be choosier.

When these so-called sex role reversals occur, such as in seahorses where the males “get pregnant” by having the female transfer her fertilized eggs into a structure termed the male’s brood pouch and hence becoming more invested in their offspring, it is the females who are larger and compete over mates, while the males are more selective. Find a species where the sex that invests less in offspring is choosier, and the theory will be disproven.

The assertion that male and female are arbitrary classifications is false on every level. Not only does it confuse primary sexual characteristics (i.e., the reproductive organs) which are unambiguously male or female at birth 99.8 percent of the time with secondary sexual characteristics (e.g., more hair on the faces of men or larger breasts in women), it ignores the very definition of biological sex — men produce many small sex cells termed sperm while women produce fewer large sex cells termed eggs. Although much is sometimes made of the fact that sex differences in body size, hormonal profiles, behavior, and lots of other traits vary across species, that these differences are minimal or non-existent in some species, or that a small percentage of individuals, due to disorders of development, possess an anomalous mix of female and male traits, that does not undermine this basic distinction. There is no third sex. Sex is, by definition, binary.

In the 50 years since Trivers’ epiphany, much has tried to obscure his crucial insight. As biology enters a golden age, with daily advances in genotyping transforming our understanding of evolution and medicine, the social sciences have taken a vastly different direction. Many are now openly hostile to findings outside their narrow field, walling off their respective disciplines from biological knowledge. Why bother learning about new findings in genetics or incorporating discoveries from other fields, if you can assert that all such findings are, by definition, sexist?

Prior to 1955, gender was almost exclusively used to refer to grammatical categories (e.g., masculine and feminine nouns in French). A major shift occurred in the 1960s when the word gender has been applied to distinguish social/cultural differences from biological differences (sex). Harvard Biologist, David Haig documented that from 1988 to 1999 the ratio of the use of “sex” versus “gender” in scientific journals shrank from 10 to 1 to less than 2 to 1, and that after 1988 gender outnumbered sex in all social science journals. The last twenty years have seen a rapid acceleration in this trend, and today this distinction is rarely observed. Indeed, the biological concept of sex in reference to humans has become largely taboo outside of journals that focus on evolution. Many, however, are not content with limiting the gender concept to humans and a new policy instituted by all Nature journals requires that manuscripts include a discussion of how gender was considered in all studies with human participants, on other vertebrates, or on cell lines. When would including gender be appropriate in a genetic study of fruit flies?

This change is not merely stylistic. Rather, it is part of a much larger cultural and political movement that denies or attempts to explain away the effects of biology and evolution in humans altogether. The prevailing dominant view in the social sciences is that human sex differences are entirely socially constructed. In that interpretation, all differential outcomes between men and women are the result of unequal social, economic, and political conditions, and so we do all we can to eliminate them, particularly by changing our expectations and encouraging gender-neutral play in children. This received wisdom and policies based upon it, however, are unlikely to produce the results proponents long for. Why is that?

Because sex differences in behavior are among the strongest effect sizes in social, and what might be better termed, behavioral sciences. Humans are notoriously inept at understanding differences between continuous variables, so it is first useful to define precisely what “statistical differences between men and women” does and does not mean. Although gamete size and the reproductive organs in humans are either male or female at birth in over 99 percent of cases, many secondary sexual characteristics such as differences in upper body strength and differences in behavior are not so differentially distributed. Rather, there is considerable overlap between men and women. Life scientists often use something called the effect size as a way to determine if any observed differences are large (and therefore consequential) or so small as to be ignored for almost all practical purposes.

Conceptually, the effect size is a statistical method for comparing any two groups to see how substantially different they are. Graphically, it can be thought of as the distance between the peaks of the two distributions divided by the width of those distributions. For example, men are on average about 6 inches taller than women in the United States (mean height for American women is 5 feet 3 inches and the mean height for American men is approximately 5 feet 9 inches). The spread of the height distributions for men and women, also known as the standard deviations, are also somewhat different, and this is slightly higher for men at 2.9 inches vs 2.8 inches for women. For traits such as height that are normally distributed (that is, they fit the familiar bell curve shape), one standard deviation on either side of the mean encompasses about 68 percent of the distribution, while two standard deviations on either side of the mean encompass 95 percent of the total distribution. In other words, 68 percent of women will be between 60.2 inches and 65.8 inches tall, and 95 percent will be between 57.5 to 68.6 inches. So, in a random sample of 1000 adult women in the U.S., approximately 50 of them will be taller than the average man (see figure above).

A large effect size, or the standardized mean difference, is anything over 0.8 and is usually seen as an effect that most people would notice without using a calculator. The effect size for sex differences in height is approximately 1.9. This is considered to be a pretty big effect size. But it is certainly not binary, and there are lots of taller-than-average women who are taller than lots of shorter-than-average men (see overlap area in figure). Therefore, when determining whether an effect is small or large, it is important to remember that the cutoffs are always to some degree arbitrary and that what might seem like small differences between the means can become magnified when comparing the number of cases that fall in the extremes of (the tails of their respective distributions) of each group.

In other words, men and women may, on average, be quite similar on a given trait but will be quite different in the number who fall at the extreme (low and high) ends of their respective distributions. This is particularly true of sex differences because natural selection acts more strongly on men, and males have had higher reproductive variance than females over our evolutionary history. That is to say that a greater number of men than women have left no descendants, while a very few men have left far more. Both the maximum number of eggs that a woman produces over the course of her reproductive life versus the number of sperm a man produces and the length of pregnancy, during which another reproduction cannot occur, place an upper limit on the number of offspring women can have. What this means is that males often have wider distributions for a trait (i.e., more at the low end and more at the high end) so that sex differences can be magnified at the tail ends of the distribution. In practical terms, this means that when comparing men and women, it is also important to look at the tails of their respective distributions (e.g., the extremes in mental ability).

The strongest effect sizes where men tend to have the advantage are in physical abilities such as throwing distance or speed, spatial relations tasks, and some social behaviors such as assertiveness. Women, meanwhile, tend to have an edge in verbal ability, social cognition, and in being more extroverted, trusting, and nurturing. Some of the largest sex differences, however, are in human mate choice and behaviors that emerge out of the evolutionary logic of Trivers’ parental investment theory. In study after study, women are found to give more weight to traits in partners that signal an ability to acquire resources, such as socioeconomic status and ambition, while men tend to give more weight to traits that signal fertility, such as youth and attractiveness.

Indeed these attitudes are also revealed in behavior such as age at marriage (men are on average older than women in every country on earth), frequency of masturbation, indulging in pornography, and paying for sex. Although these results are often dismissed, largely on ideological grounds, the science is rarely challenged, and the data suggest some biological difference (which may be amplified, indeed enshrined, by social practices).

The evidence that many sex differences in behavior have a biological origin is powerful. There are three primary ways that scientists use to determine whether a trait is rooted in biology or not. The first is if the same pattern is seen across cultures. This is because the likelihood that a particular characteristic, such as husbands being older than their wives, is culturally determined declines every time the same pattern is seen in another society — somewhat like the odds of getting heads 200 times in a row. The second indication that a trait has a biological origin is if it is seen in young children who have not yet been fully exposed to a given culture. For example, if boy babies are more aggressive than girl babies, which they generally are, it suggests that the behavior may have a biological basis. Finally, if the same pattern, such as males being more aggressive than females, is observed in closely related species, it also suggests an evolutionary basis. While some gender role “theories” can attempt to account for culturally universal sex differences, they cannot explain sex differences that are found in infants who haven’t yet learned to speak, as well as in the young of other related species.

Many human sex differences satisfy all three conditions — they are culturally universal, are observable in newborns, and a similar pattern is seen in apes and other mammals. The largest sex differences found with striking cross-cultural similarity are in mate preferences, but other differences arise across societies and among young children before the age of three as boys and girls tend to self-segregate into different groups with distinct and stereotypical styles. These patterns, which include more play fighting in males, are observable in other apes and mammal species, which, like humans, follow the logic of Trivers’ theory of parental investment and have higher variance in male reproduction, and therefore more intense competition among males as compared to females.

If so, why then has the opposite message — that these differences are either non-existent or solely the result of social construction — been so vehemently argued? The reason, I submit, is essentially political. The idea that any consequential differences between men and women have no foundation in biology has wide appeal because it fosters the illusion of control. If gender role “theories” are correct, then all we need to do to eliminate them is to modify the social environment (e.g., give kids gender-neutral toys, and the problem is solved). If, however, sex differences are hardwired into human nature, they will be more difficult to change.

Acknowledging the role of biology also opens the door to conceding the possibility that the existence of statistically unequal outcomes for men and women are not just something to be expected but may even be…desirable. Consider the so-called gender equality paradox whereby sex differences in personality and occupation are higher in countries with greater opportunities for women. Countries with the highest gender equality,24 such as Finland, have the lowest proportion of women who graduate college with degrees in stereotypically masculine STEM fields, while the least gender equal countries such as Saudi Arabia, have the highest. Similarly, the female-to-male sex ratio in stereotypically female occupations such nursing is 40 to 1 in Scandinavia, but only 2 to 1 in countries like Morocco.

The above numbers are consistent with cross-cultural research that indicates that women are, on average, more attracted to professions focused on people such as medicine and biology, while men are, again, on average, more attracted to professions focused on things such as mathematics and engineering. These findings are not a matter of dispute, but they are inconvenient for gender role theorists because they suggest that women and men have different preferences upon which they act when given the choice. Indeed, it is only a “paradox” if one assumes that sex is entirely socially constructed. As opportunities for women opened up in Europe and the United States in the sixties and seventies, employment outcomes changed rapidly. However, the proportions of men and women in various fields stabilized sometime around the early 1990s and have barely moved in the last thirty years. These findings imply that there is a limited capacity for outside interventions imposed from the top down to alter these behaviors.

In the cold logic of evolution, neither sex is, or can be, better or worse. Although this may not be the kind of equality some might want, we need to move beyond simplistic ideas of hierarchy.

It is understandable, however, for some to fear that any concession to nature will be used to justify and perpetuate bias and discrimination. Although arguments for why women should be prohibited from certain types of employment or why they should not be allowed to vote were ideological, sex differences have been used to justify a number of historical injustices. Still, is the fear of abuse so great that denying any biological sex differences is the only alternative?

The rhetorical contortions and inscrutable jargon required to assert that gender and sex are nothing more than chosen identities and deny what every parent knows require increasingly complex and incoherent arguments. This not only subverts the public’s rapidly waning confidence in science, but it also leads to extreme exaggerations designed to silence those who don’t agree, such as the claim that discussing biological differences is violence. The lengths to which many previously trusted institutions, such as the American Medical Association, go to deny the impact that hormones have on development are extraordinary. These efforts are also likely to backfire politically when gender-neutral terms are mandated by elites, such as the term “Latinx,” which is opposed by 98 percent of Hispanic Americans.

Acknowledging the existence of a biological basis for sex differences does not mean that we should accept unequal opportunities for men and women. Indeed, the crux of the problem lies in conflating equality with statistical identity and in our failure to respect and value difference. These differences should not be ranked in terms of inferior or superior, nor do they have any bearing on the worth or dignity of men and women as a group. They cannot be categorized as being either good or bad because it depends on which traits you want to optimize. This is real diversity that we should acknowledge and even celebrate.

Ever since the origin of sexual reproduction approximately two billion years ago, sexual selection, governed by an initial disparity in the size of the sex cells, has driven a cascade of differences, a few absolute, many more statistical, between males and females. As a result, men and women have been experiencing distinct evolutionary pressures. At the same time, however, this process has ruthlessly enforced an equality between the sexes, ensured by the fact that it takes one male and one female to reproduce, which guarantees the equal average reproduction of men and women. The production of sons and daughters, who inherit a near equal split of their parents’ genetic material, also demands that mothers and fathers contribute equally to their same- and their opposite-sex children. In the cold logic of evolution, neither sex is, or can be, better or worse. Although this may not be the kind of equality some might want, we need to move beyond simplistic ideas of hierarchy, naively confusing difference with claims of inferiority/superiority, or confusing dominance with power. In the currency of evolution, better just means more copies, dominance only matters if it leads to more offspring, and there are many paths to power.

The assertion that children are born without sex and are molded into gender roles by their parents is wildly implausible. It undermines what little public trust in science remains and delegitimizes other scientific claims. If we can’t be honest about something every parent knows, what else might we be lying about? Confusion about this issue leads to inane propositions, such as a pro-choice doctor testifying to Congress asserting that men can give birth. When people are shamed into silence about the obvious male advantages in almost all sports (but note women do as well or better in small bore rifle competition, and no man can match the flexibility of female gymnasts) and when transgender women compete in women’s sports, it endangers the vulnerable. When children are taught that all sex differences are entirely grounded in mere identity (whether self-chosen or culturally-imposed) and are in no way the result of biology, more “masculine” girls and more “feminine” boys may become confused about their sex, or sexual orientation, and harmful stereotypes can take over. The sudden rapid rise in the number of young girls diagnosed with gender dysphoria is a warning sign of how dangerously disoriented our culture can become.

Pathologizing gender nonconforming behavior often does the opposite of what proponents intend by creating stereotypes where none existed. Boys are told that if they like dolls, they are really girls trapped with male organs, while girls who display interests in sports or science are told they are boys trapped with female organs and born in the wrong body. Feminine boys, who might end up being homosexual, are encouraged to start down the road towards irreversible medical interventions, hormone blockers, and infertility. Like gay conversion therapy before, such practices can shame individuals for feeling misaligned with their birth sex and encourage them to resort to hormone “therapy” and/or surgery to change their bodies to reflect this new identity. Can that be truly seen as progressive and liberating?

The push for a biologically sexless society is an arrogant utopian vision that cuts us off from our evolutionary history, promotes the delusion that humans are not animals, and undercuts respecting each individual for their unique individuality. Sex is neither simply a matter of socialization, nor a personal choice. Making such assertions without understanding the profound role that an initial biological asymmetry in gamete size plays in sexual selection is neither scientific nor sensible. 

-

Robert Lynch is an evolutionary anthropologist at Penn State who specializes in how biology, the environment, and culture transact to shape life outcomes. His scientific research includes the effect of religious beliefs on social mobility, sex differences in social relationships, the impact of immigration on social capital, how social isolation can promote populism, and the evolutionary function of laughter.

==

I've said before that I learned more about evolution as a result of combatting evolution denial from the religious than I ever did at school. It's similarly true that I've learned more about sex, biology, chromosomes, genes and hormones as a result of the sex-denialism and anti-science attitudes of the gender cult.

[dimetrodone]

Anisogamy feels like something that would more likely evolve in complex multicellular life but I kinda want to make some of my aliens isogamous just to play around with the idea

[weeswageningen]

Dear all,

We would like to invite you to attend March’s Wageningen Evolution & Ecology Seminar (WEES) and Workshop.

The seminar will take place on Thursday 21st March, 16.00-17.00 in C1005 in Orion. This will be followed by drinks at The Spot and the opportunity to have dinner (at your own expense) with the speaker. Sign up for dinner with Ruth Fawthrop (r.fawthrop@nioo.knaw.nl).

The associated workshop will be from 14.00-15.30 in B4014 in Orion. The workshop gives attendees the opportunity to meet the seminar’s speaker and have a discussion about a hot topic in science. Furthermore, BSc and MSc students can get 1 ECTS for attending 2 workshops. Registration is required for this workshop and you can sign up by emailing Ruth Fawthrop (r.fawthrop@nioo.knaw.nl).

This will be a great event so please forward this information to anyone who could be interested!

Seminar: Mate choice, extra-pair paternity and social networks (16.00h in C1005, Orion)

Dr. Julia Schroeder

Senior Lecturer

Imperial College London, UK

Female mate choice is one of the hallmarks of sexual selection. Driven by anisogamy, females are predicted to be the choosier sex, selecting her mates by aiming to maximise the quality of her offspring, while males are predicted to favour quantity over quality. Extra-pair paternity in socially monogamous song birds is a model system where this female choice is put under magnification: females exchange the genetic contribution of the father, but the rest stays the same. This system allows us to test several predictions from sexual selection and beyond. Here I will explore the classical sexual selection hypotheses (good genes, sexy sons), more recent suggestions (pleiotropy hypotheses) and the roles of ageing, opportunity and connectedness in mate choice. I will present data from 25 years of research in our island system of house sparrows.

Workshop: Time management and life-work balance in academia (14.00h in B4014, Orion)

In this workshop we will explore the ongoing issues academics face surrounding time management and life-work balance. We will consider how we define personal productivity and how ecologists and evolutionary biologists can consider their own time management practices.

As an introduction to the workshop, attendees are encouraged to read the following article: https://www.nature.com/articles/d41586-024-00648-x

About WEES

WEES is an initiative of PhD students and postdocs at Wageningen University to organize a continuing series of stimulating seminars on contemporary topics in evolution and ecology. For this series we invite researchers from all over the world who have leading roles in their field. We aim to bring together different groups at Wageningen University using a variety of systems, but with a common interest in evolutionary and ecological questions. WEES is funded by graduate schools PE&RC, WIMEK, EPS, VLAG, and WIAS. 

Want to organize seminars yourself? Join WEES!

WEES is looking for new members! We aim for a broad and diverse range in topics and would like to welcome new members to help and include topics not represented yet. If you are curious, send an email to weeswageningen@gmail.com and join one of our meetings. 

For more information please visit www.weeswageningen.nl and follow us on twitter @weeswageningen

[i-should-have-studied]

Reproduction in Protozoa

Asexual Reproduction: there are 5 ways a protozoan can undergo asexual reproduction: Binary Fission, Plasmotomy, Budding, Multiple Fission, and Plasmogamy.

Binary Fission: the division of one individual cell into two approx. equal parts. It's a type of mitosis where karyokinesis is always followed by cytokinesis. Ex: Amoeba

Plasmotomy: A special type of binary fission, it divides a multinucleate mother cell into two or more multinucleate daughter cells. Ex: Pelomyxa

Budding: Modified fission resulting in a small daughter bud attached to the mother cell. When the bud is broken off, it develops and grows into full size. When a parent produces one bud, it's called monotonic. When a parent produces numerous buds at once, it's called multiple budding. Ex: Vorticella

Multiple Fission: aka Sporulation, Nuclear division is not immediately followed by the division of cytoplasm. The nucleus undergoes a series of divisions till the body becomes multinucleate. After, the cytoplasm divides into the same number of parts as there are daughter nuclei, each surrounds a nucleus. Finally, the body divided simultaneously into numerous daughter cells. The number of daughter cells can vary. Ex: Plasmodium

Plasmogamy: Two or more individuals fuse their cytoplasm, but keep their nuclei distinct. They separate later, unchanged. This sometimes serves the purpose of digestion of large prey. Ex: Rhizopoda

Sexual Reproduction: There are two types of sexual reproduction: Syngamy and Conjugation.

Syngamy: Complete fusion of two sex cells/gametes, creates a zygote. The fusion nucleus of zygote is called synkaryon. Is of 4 subtypes: Hologamy, Isogamy, Anisogamy, Autogamy.

Hologamy: Mature protozoans behave like gametes and fuse together

Isogamy: fusing gametes are similar in size and shape

Anisogamy: fusing gametes differ morphologically and behaviorally.

Autogamy: fusing gametes ae derives from the same parents cell.

Conjugation: The temporary union of two individual conjugants. Usually at oral or buccal regions of their body. ex: Suctoria

Parthenogenesis: Gametes which fail at cross-fertilization (syngamy) develop parthenogenically. ex: Chlamydomonas

Regeneration: Most protozoans can regenerate lost parts.

[evoldir]

Fwd: Postdoc: Roscoff_France.TheoreticalEvolutionaryGenetics

Begin forwarded message: > From: evoldir@evol.biology.mcmaster.ca > Subject: Postdoc: Roscoff_France.TheoreticalEvolutionaryGenetics > Date: 25 January 2023 at 07:43:18 GMT > To: rdmpage@gmail.com > > > Postdoctoral position - Roscoff, France - Modeling the early evolution > of life cycles and reproductive systems. > > A 3 years postdoctoral position is open at Roscoff's Biological Station > (https://ift.tt/HpyLUzE), to work with Denis Roze on a collaborative > project leaded by Susana Coelho (Max Planck Institute for Biology, > T�bingen) on the evolution of multicellularity and the emergence of > life cycles and reproductive systems, financed by the Gordon and Betty > Moore Foundation. > > Context: the general objective of the project is to identify key genetic > and regulatory changes that have been involved in the early evolution of > multicellularity in the brown algal lineage, and to better understand the > selective forces that may have moulded the life cycles and reproductive > systems of early multicellular organisms.  The project will thus combine > single-cell RNAseq, genomic and functional genetic approaches (developed > in MPI T�bingen) and theoretical approaches based on population genetic > modeling (developed in Roscoff). > > Main mission: the postdoctoral researcher will construct and analyze > theoretical models exploring the joint evolution of several aspects > of life cycles and genetic systems that have mostly been considered > independently of each other: for exampled, the joint evolution of > investment into sexual reproduction, mating types and degree of anisogamy, > and/or the joint evolution of the relative degree of development > in the haploid or diploid phase of the life cycle and investment > into sex. These questions will be addressed using a combination of > analytical and individual-based simulation models, taking into account the > possibility that selection may act at different levels within populations > of early multicellular organisms: between organisms, and between cells > within organisms. Other questions relative to the evolution of sex > determination systems, sexual dimorphism or gene regulation systems may > also be explored, depending on the interests of the selected candidate. > > Skills: candidates should hold a PhD in evolutionary biology and have > experience in mathematical modeling and programming. Previous experience > in theoretical population genetics modeling will be preferred. Candidates > should also have a good level of English and be able to work in autonomy. > > Work conditions: the postdoctoral researcher will be based at Roscoff's > Biological Station (2h by train from Rennes, 3h20 from Paris) located on > the scenic coast of North-West Brittany, with ferry connections to the UK > and Ireland, and many possibilities for outdoor activities and nautical > sports. Research at the marine station covers a large variety of fields > from cell biology to evolutionary biology and ecology. Lab meetings are in > English, knowledge of French is not mandatory. Salary will follow rules > from the CNRS and depends on the previous experience of the successful > candidate. The contract would ideally start before summer 2023. > > Application: applicants should send their CV with full publication list, > cover letter, names and email addresses of two referees to Denis Roze > (roze@sb-roscoff.fr). > > Denis Roze > > IRL3614 CNRS - Sorbonne Universit� > > Station Biologique de Roscoff > > Place Georges Teissier, CS90074 > > 29688 Roscoff Cedex, France > > > > Denis Roze

[gendont]

How do we class people who don’t produce gametes?

Non-intersex males and females can be infertile, we know their sex because of the type of gonadal tissue they have, either ovarian or testicular exclusively.

For intersex people with exclusively streak gonads and no testicular or ovarian tissue, they are female.

If they have both tissues, then if they have a full teste, they are male. If they only have ovotestes, they are female.

[religion-is-a-mental-illness]

By: Richard Dawkins

Published: Jul 26, 2023

In 2011, I was invited to guest edit the Christmas double issue of the New Statesman. I enjoyed the experience, which involved a visit to Christopher Hitchens in Texas to conduct what turned out to be his last interview. I didn’t ask him, “What is a woman?” In 2011, it wouldn’t have occurred to anyone to ask such a daft question. Today it is hurled at embarrassed and perplexed politicians, in tones that are challenging to the point of belligerence. It isn’t hard to imagine Hitchens’ response if he could be asked it today.

My main contribution to that Christmas issue was a long essay on “The tyranny of the discontinuous mind”. Everywhere you look, smooth continua are gratuitously carved into discrete categories. Social scientists count how many people lie below “the poverty line”, as though there really were a boundary, instead of a continuum measured in real income. “Pro-life” and pro-choice advocates fret about the moment in embryology when personhood begins, instead of recognising the reality, which is a smooth ascent from zygotehood. An American might be called “black”, even if seven eighths of his ancestors were white.

Anthropologists quarrel over whether a fossil is late Homo erectus or early Homo sapiens. But it is of the very nature of evolution that there must be a continuous sequence of intermediates. You can vote on your 18th birthday but not before, as though the stroke of midnight signals a quantum leap in your political competence. Universities award first-, upper second-, lower second- and third-class degrees, even though everyone knows that the top of any one class is much further from the bottom of the same class than it is from the bottom of the class above. There are Oxford dons with faith in something they call “the alpha mind”, a Platonic “ideal form”, like a perfect triangle hanging pristine and aloof above messy reality.

If the editor had challenged me to come up with examples where the discontinuous mind really does get it right, I’d have struggled. Tall vs short, fat vs thin, strong vs weak, fast vs slow, old vs young, drunk vs sober, safe vs unsafe, even guilty vs not guilty: these are the ends of continuous if not always bell-shaped distributions. As a biologist, the only strongly discontinuous binary I can think of has weirdly become violently controversial. It is sex: male vs female. You can be cancelled, vilified, even physically threatened if you dare to suggest that an adult human must be either man or woman. But it is true; for once, the discontinuous mind is right. And the tyranny comes from the other direction, as that brave hero JK Rowling could testify.

Sex is a true binary. It all started with the evolution of anisogamy – sexual reproduction where the gametes are of two discontinuous sizes: macrogametes or eggs, and microgametes or sperm. The difference is huge. You could pack 15,000 sperm into one human egg. When two individuals jointly invest in a baby, and one invests 15,000 times as much as the other, you might say that she (see how pronouns creep in unannounced) has made a greater commitment to the partnership.

Anisogamy is the rule in most animals, but it hasn’t always been so. Some primitive animals and plants are still “isogamous”: instead of macrogametes and microgametes, they have medium-sized (iso)gametes. Both partners contribute equally to the joint investment. To make a viable zygote you need the sum of two isogametes, each worth half a zygote. The same requisite sum can be achieved if one partner contributes a slightly smaller isogamete, but this will work only if the other partner chips in with a larger isogamete to redress the shortfall. You could say the minority investor is exploiting the partner who commits the larger gamete.

You can perhaps see where this argument is going, and it has indeed been modelled mathematically. Isogamy is unstable. Under plausible conditions, we get runaway evolution towards some individuals making smaller and smaller gametes, while others go in the other direction, making larger and larger gametes. At the end of the runaway, we now have microgametes that actively seek out macrogametes, and they evolve wriggling tails to propel their pursuit. Macrogametes are in demand, and have no need to go out looking for microgametes. Because microgametes are so small, individuals who make them can afford to make many. Macrogametes have to be few because, as economists love to say, there’s no such thing as a free lunch. The imbalance also means that microgamete producers (“he/him”) can mate with lots of different macrogamete producers (“she/her”), deserting each one in turn. Or they can sequester for themselves a harem of she/hers. There’d be no point in a she/her gathering a harem of he/hims around her: she doesn’t have enough macrogametes to benefit.

The anisogamy binary furnishes the oldest and deepest way to distinguish the sexes. There are others, but they are less universally applicable. In mammals and birds, you can do it with chromosomes. Each body cell of a normal human has 46 chromosomes, 23 from each parent. Among these are two sex chromosomes, called X or Y, one from each parent. Females have two Xs, males one X and one Y. Any mammal with a Y chromosome will develop as a male. When a male makes sperm (“haploid”, having only one set of 23 chromosomes), 50 per cent of them are Y sperm, destined to beget sons, and 50 per cent are X sperm, which make daughters. Birds and butterflies have a similar system, but the other way around. It is females that have XY, except that they’re called ZW. In flies, the equivalent of the Y chromosome is a zero. If a fly has two sex chromosomes she’s female. A fly with only one sex chromosome is male. Many reptiles use temperature instead of chromosomes. Turtles that are incubated below 27.7°C develop as male, warmer eggs as female.

Clownfish determine sex not by temperature but by dominance. All but one of the members of a group are male, and like many animals they sort themselves into a dominance hierarchy. There is only one female in the group. When she dies, the dominant male changes sex and becomes the female. What this means in gametic terms is that his testes shrink and ovaries grow instead. The principle of binary sex at the level of micro- and macro-gametes is maintained. Hermaphrodites such as earthworms and land snails have testes and ovaries all in the same body at the same time. Snails are capable of exchanging sperm both ways, having first violently fired harpoons into each other. Angler fish also have both male and female organs in the same body. But it comes about in a curious way. Males are diminutive dwarves; they locate a female, sink their jaws into her body wall, and then become part of her as no more than a tiny testicular excrescence.

In mammals, including humans, there are occasional intersexes. Babies can be born with ambiguous genitalia. These cases are rare. The highest estimate, 1.7 per cent of the population, comes from the US biologist Anne Fausto-Sterling. But she inflated her estimate hugely by including Klinefelter and Turner syndromes, neither of which are true intersexes. Klinefelter individuals have an extra X chromosome (XXY) but their Y chromosome ensures that they are obvious males, producing microgametes, albeit from reduced testes. Turner individuals are unambiguous females with no Y chromosome and only one (functioning) X chromosome. They have a vagina and uterus, and their ovaries, if any, are non-functional. Obviously, Klinefelter (always male) and Turner (always female) individuals must be eliminated from counts of intersexes, in which case Fausto-Sterling’s estimate shrinks from 1.7 per cent to less than 0.02 per cent. Genuine intersexes are way too rare to challenge the statement that sex is binary. There are two sexes in mammals, and that’s that.

But what about gender? What is gender, and how many genders are there? It is now fashionable to use “gender” for what we might call fictive sex: a person’s “gender” is the sex to which they feel that they belong, as opposed to their biological sex. In this meaning, “genders” have proliferated wildly. When I last heard, there were 83. But that was yesterday. What does “gender” actually mean?

Language evolves, and many words change their meaning on a timescale of centuries. But “gender” has been fast-tracked. It is primarily a linguistic technical term. Linguists classify words of a given language according to such things as the suffixes on adjectives that qualify them, or their agreeing pronouns and articles. All French nouns follow either le or la. They take different pronouns, and adjectives agree with them in a gendered way (le chapeau blanc but la robe blanche). Normally (there are exceptions, such as la souris for a mouse of either sex) males are le and females la. This makes it convenient to use the label “masculine” for le words and “feminine” for la words. Table is a feminine word, but French speakers don’t think of a table as a female piece of furniture. It’s just a la word. Lithuanian also has two genders, but possessive pronouns agree with the gender of the possessor (as in English) whereas in French they agree with the gender of the object possessed. Estonian has only one gender, which I suppose means no gender – the very idea of gender is meaningless. Some Bantu languages such as Nyanja, the dominant language of my childhood home of Malawi, have many. Steven Pinker’s The Language Instinct quotes Kivunjo as having 16 genders. These are not 16 sexual identities, they are 16 families of nouns classified according to how verbs agree with them.

In English, as in French, gender and sex align. All female animals are of feminine gender, all males are masculine, all inanimate things are neuter (with whimsical exceptions such as ships and nations, which can be feminine). Because of the perfect correlation between sex and gender in English grammar, it was natural for English speakers to adopt “gender” as a genteel euphemism for sex: “Sam is of female gender” sounded more polite than “of female sex”.

But that convention recently gave way to another one. The fashion for females to “identify as” male and for males to “identify as” female has emplaced an assertive new convention. Your genes and chromosomes may determine your sex, but your gender is whatever floats your boat: “I was assigned male at birth, but I identify as a woman.” Finally, the wheel turns full circle, and self-identification has now gone so far as to usurp even “sex”. A “woman” is defined as anyone who chooses to call herself a woman, and never mind if she has a penis and a hairy chest. And of course this entitles her to enter women’s changing rooms and athletic competitions. Why should she not? She is, after all, a woman, is she not? Deny it and you are a transphobic bigot.

High priests of postmodernism teach that lived experience and feelings trump science (which is just the mythology of a tribe of oppressive colonialists). Catholic (but not Protestant) theologians declare that consecrated wine actually becomes the blood of Christ. The dilute alcohol solution that remains in the chalice is but an Aristotelian “accidental”. The “whole substance” (hence the word “transubstantiation”) is divine blood in true reality. In the new religion of transsexual transubstantiation, a “woman’s penis” is just an “accidental”, a mere social construct. In “whole substance” she is a woman. A trans-substantiated woman.

Sarcasm aside, gender dysphoria is a real thing. Those who sincerely feel themselves born in the wrong body deserve sympathy and respect. I was convinced of this when I read Jan Morris’s moving memoir, Conundrum (1974). As what she called a “true transsexual”, she distanced herself from “the poor cast-aways of intersex, the misguided homosexuals, the transvestites, the psychotic exhibitionists, who tumble through this half-world like painted clowns, pitiful to others and often horrible to themselves”. Under “misguided” she might have added today’s unfortunate children who, latching on to a playground craze, find themselves eagerly affirmed by “supportive” teachers, and au courant doctors with knives and hormones. See Abigail Shrier’s Irreversible Damage: The Transgender Craze Seducing Our Daughters (2020); Kathleen Stock’s Material Girls: Why Reality Matters for Feminism (2021); and Helen Joyce’s Trans: When Ideology Meets Reality (2021). Many of us know people who choose to identify with the sex opposite to their biological reality. It is polite and friendly to call them by the name and pronouns that they prefer. They have a right to that respect and sympathy. Their militantly vocal supporters do not have a right to commandeer our words and impose idiosyncratic redefinitions on the rest of us. You have a right to your private lexicon, but you are not entitled to insist that we change our language to suit your whim. And you absolutely have no right to bully and intimidate those who follow common usage and biological reality in their usage of “woman” as honoured descriptor for half the population. A woman is an adult human female, free of Y chromosomes.

[another-cliche-title]

this is so true b/c when it comes to "so what makes a animal biologically male or female?", humans just casually project their socially constructed ideas of gender, like "alpha/beta male" coming from the (False) understanding of wolf courtship/social behavior. which then reinforces our ideas of gender cuz we essentialize it using our interpretations of animal behavior which are 1) incorrect 2) ok yeah "humans are basically animals" but you are not a fucking wolf

it's kind of a pop science version of "The Serpent Crawls On His Belly for the Sins He Has Committed"

so to answer the question of "what makes animals biologically male or female", you can look at all the animals and realize "Damn!! Animal sexual reproductive stuff is more diverse than i realize!". like in post above but i just wanna spam my knowledge

sequential hemaphroditism. basically animals giving themselves a sex change. some ppl flipped out b/c their transphobes and this means that clownfish are trans

XX/XY is not the only thing out there, even in humans (intersex). in some animals, they have the ZW sex determination system (birds, some insects, lots of reptiles) where male is ZZ and female is ZW

not to mention we overly gender sex chromosomes because Sex Determination Is Only One Part of the Damn Thing. like X chromosomes carry colors in cats, which is why calicos have two X chromosomes while it's impossible for XY to be calico (warrior cats tumblr taught me this lmao)

this sucks because it's common for people to suggest that intersex ppl with multiple y chromosomes are more masculine and therefore Commit Crimes and Do Violence esp. in some media depictions of intersex ppl (less common now but still!)

the transcaucasian mole vole only has the X chromosome. it has male and female sexes but literally nobody knows how they determine sex. potentially, humans could evolve to lose the Y chromosome and be like our mole vole friends. chromosome loss isn't that freaky or weird in evolution b/c that usually just means that other chromosomes take on more of the responsibilities of one, creating conditions for it to gradually go away as it is no longer needed. a lot of species have sex determined by more than 2 genes too!! damn!!!

ok i realized that i haven't answered "So what makes a animal male or female if it isn't XX/XY?". well the simple answer is "Kind of nothing lol". the only real definition depends on the gametes. male gametes are usually tiny af and motile while female gametes are giant and immobile.

isogamy is when the gametes are p much the same!

anisogamy is when gametes are different (male/female)

some animals have "mating types" instead of "sex" which is kind of a whole nother thing, but they also have differentiated gametes

i kind of infodumped here but the takeaway is that humans project our ideas of gender onto animals too much when we are not fucking wolves or chimps while we casually ignore animal behavior that doesn't fit that mold.

Every time I see that "bees and ants don't have human genders" thing I beat my head against something. No animal has human genders, guys. *NO* animal.

[uniquevocashark]

I'm thinking about castello and igraine

[incarnation-issues]

This blog takes the position that cishumanist feminism is incorrect, and also that the cishumanism/transhumanism split within feminism is real and probably important. (Conservative stances on any given novel technology will of course sometimes be right, but transhumanists can still be cautious and hesitant about change.)

[cats-moss-gays]

A Defense of Biological Sex - The Paradox Institute

From The Paradox Institute on Youtube. Also check out their website, which is where I found the transcript for this video and others.

Imagine, for a moment, if we as a society replaced the biological categories of male and female with socially defined identities. In this world, no person, system, or institution would differentiate between male and female. Instead, each individual defines themselves according to their own internal subjective perception. It may sound progressive or inclusive, but what would happen? Here’s nine reasons why biological sex (male and female) must be defended. 

#1. Truth - Science matters, and reality matters. The famous theoretical physicist Richard Feynman once said, "It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong." We progress by testing our assumptions against reality. If reality doesn’t agree, we must adjust our assumptions. Holding onto incorrect theories in the face of nature leads to nature roaring back with a vengeance.

#2. Reproduction - 1.2 billion years old, sexual reproduction is fundamental to life. In humans, as in most animals and plants, reproduction occurs through anisogamy, the fusion of two gametes which differ in size and form. Males develop a reproductive system organized around small gametes (sperm), and females develop a reproductive system organized around large gametes (ova). Without this system, Homo sapiens, and most other animals, would not exist. As two evolutionary biologists write in their paper, Gamete competition, gamete limitation, and the evolution of the two sexes, "The question of the origin of the two sexes is equal to the question of why do gametes come in two different sizes."

#3. Evolution - The existence of two sexes shaped our physical and cognitive evolution as a species. Sexual selection pressures produced the dimorphism of male and female bodies, led to the evolution of our brains, and built entire societies. The development of culture, art, and technology are, in part, the result of sexual selection on creativity and intelligence. In his book, The Mating Mind, evolutionary psychologist Geoffrey Miller writes, "The human mind’s most impressive abilities are like the peacock’s tail: they are courtship tools, evolved to attract and entertain sexual partners." Thus, to understand ourselves as a species requires us to understand the evolution of the two sexes.

#4. Medicine - Understanding sex differences is critical for the application and development of safe and effective medical practices. For instance, emergency medicine must identify the sex of the patient for appropriate drug dosages and blood transfusions; sex-specific diseases such as prostate cancer in males and endometriosis in females require knowledge of the reproductive tract; and sex-related diseases and psychiatric illnesses, such as depression, anxiety disorders and personality disorders, manifest differently in males and females. Thus, sex differences in gene expression, hormone levels, and the reproductive system influence the effectiveness of medical treatments, pharmaceutical drugs, and psychiatric practices. Without understanding the genetic, hormonal, and psychological differences within and between males and females, medical research fails to function.

#5. Sports - Competitive sports are divided on the basis of sex for a reason. Compared to the average female, the average male has 33% more lower body muscle mass, 40% more upper body muscle mass, and 57% more grip strength. Plot a graph of grip strength data points, and you’ll find that the strongest 10% of females can only beat the bottom 10% of males. Overall, the male performance advantage compared to females is 10-50% depending on the sport. Elimination of biological sex as a criterion for sports marks the end of the female sports category.

#6. Crime - Informed public policy requires an accurate understanding of crime statistics, including sex differences in crime rates. The truth is that the overwhelming majority of violent crime, including aggravated assault, robbery, murder, and rape, is committed by males. In the United States, men commit 77% of aggravated assaults, 87% of robberies, 87% of murders, and 98% of rapes. Without tracking crime statistics by sex, policies such as single-sex spaces, designed to protect women and girls from predatory males, would have no statistical foundation.

#7. Safety and Privacy - Separating males and females into single-sex public bathrooms, changing rooms, and prisons, where people undress and are vulnerable, increases the safety of females from actions of predatory males, and it retains the privacy and dignity of both sexes. Where such distinctions between male and female spaces are violated, injustice follows. For example, in UK swimming pool and sports-center changing rooms, from 2017-2018, 90% of reported sexual assaults, harassment, and voyeurism happened in unisex facilities. Only 10% occurred in single-sex changing rooms. This pattern continues when males are sent to female prisons. In Wakefield, England, in 2017, a male rapist was admitted into a female prison. Why? Because he identified as a woman. While there, he sexually assaulted two female inmates. In 2019, 1 in 50 male prisoners in the UK claimed to be women. What would happen if those male inmates were also sent to female only prisons? Without single-sex spaces, the safety and privacy for women and girls would be lost.

#8. Fighting Injustice - Females across the world are subjected to sex-specific injustices. Practices such as female genital mutilation (FGM), sex-selective abortions, and sex slavery are still common throughout the world. Take female genital mutilation. Concentrated in the Middle East, Asia, and Africa, it is estimated that more than 200 million girls and women alive today have experienced FGM. Many countries have rates over 70%. For example, in the east African country of Somalia, 98% of girls and women aged 15 to 49 have undergone FGM. In Ethiopia, 74%. In Sudan, 88%. And in Egypt, 91%. These girls and women are not targeted because they identify as female, but because they are female. Without differentiating between male and female, we cannot fight sex-specific injustices.

And finally, #9. Equality - Sex-based legal protections, laws, and policies are all informed by differentiating between male and female. We cannot make informed policies if we do not recognize the different reproductive functions of men and women and how such functions impact life choices. For example, only females can become pregnant and carry a child, which heavily impacts life and work choices. Therefore, social policy must consider such sex differences to provide men and women with equal opportunities and equality under the law. Without recognizing male and female as biological categories, sex-based equality cannot be achieved.

So, with that, reconsider the initial proposition: What if the biological categories of male and female were replaced with socially defined identities? The answer is, wherever biological sex is a critical aspect of life and is replaced by subjective perception, ignorance and injustice would follow. We’d witness the elimination of equality under the law, the inability to combat sex-based injustice, the erosion of safety and privacy for women and girls, and the inability to record accurate crime statistics. We’d witness the end of the female sports category, the collapse of evidence-based medicine, the ignorance of our evolution, and the abandonment of truth. Biological sex matters. It’s time to defend it.

[heyitschartic]

Okay for those that don't know, in WoW when the universe was created some of the planets in it randomly had a world soul which is basically like the egg of a god, which are called the Titans. Now, the other Titans kinda keep watch over the various planets in the universe and whatever and make sure everything's on the up and up. Now there's also this thing called the Void which we won't get too deep into but it's basically a sentient force of nothingness that wants to pull everyone back into it and in order to do that sent void lords all over the universe to corrupt planets.

Now, these things are basically Old Gods from HP Lovecraft and when they landed on Azeroth they found the powerful world soul and were like "jackpot." Then the Titans found Azeroth with this powerful world soul being corrupted and were like "oh no." So they beat the shit out of these guys but since they couldn't pull them out without killing the planet imprisoned them inside of it.

This is where the Earthen come in.

The Titans created the Earthen as stone beings to keep watch on Azeroth and make sure the Old Gods didn't get out of their prisons. Now, these idiots did a fuck-ass job of it cause basically every single Old God got out at some point, but that's not really relevant. What is relevant is that one of them, Yogg-Saron, got out and was like "fuck these Earthen are hard to corrupt," and so he gave them the curse of flesh which turned them into Dwarves with skin and blood and bones and all that.

Now, here's the thing. The Earthen don't have kids. Since they're literally metal and stone they're created in factories that are really weird to have in a fantasy universe. So, we get to the crux of the question. Do. They. Have. Dicks???

They can't, can they? Like, why would they add dicks and vaginas to the Earthen? They aren't meant to be having sex. But obviously the Dwarves are having sex, or else how would they have children? To add another layer to it, the Titans didn't create all the beings on Azeroth, at least not directly like this. See, there are other creatures on Azeroth like Elves and Trolls that arose naturally from what was essentially sped up evolution and they have no connection to all this stupid shit and they also 100% have dicks (I checked personally: Moonguard realm, Goldshire Inn, hit me up).

So, then did this fucking Old God add a dick to the Earthen??? Why would he do that????? Did the Titans just sort of model these guys after other life forms on this planet and were like "oh most of these creatures have anisogamy, perhaps that is crucial to their function? Oh well, just slap it on." But then why model it after the creatures on the planet??? Are they stupid???? Actually, we meet the Titans later and know for a fact they are pretty fucking dumb.

I don't know, there's just so many questions and not enough answers. My girlfriend is convinced the Earthen do have dicks cause, in her words, "haven't you seen the Yonic nature of caves and rock formations," and also "what do you think Stalagmites are?" Both good points, and both things I can't refute.

I guess we'll never know...

My girlfriend and I have been arguing for the past three days about whether Earthen have dicks

[academicelephant]

The origins of sexual selection

Anisogamy means that gametes of the sexes are different in size, while isogamy means that the gametes of the sexes are of the same size. Though in species with games of the same size we don’t speak about ‘sexes’ but ‘reproduction types’, meaning which of the gametes are compatible with each other. The most common number of reproduction types is two, but there are species with three, seven and even more types.

In the beginning all gametes within the species on our planet were of the same size but different selection pressures have led to differentiation in the gamete sizes. There are three factors that contributed to it: 

life originated in the sea and species that reproduce sexually released their gametes into the water where they fertilized the gametes of other individuals 

one can produce more small gametes than large gametes

the bigger the zygote, the better chances it has to survive

Small and fast gametes won the fertilization race, while large gametes can provide the most energy. Because of their slowness, the medium-sized gametes have not been able to win the fertilization race, and because of their smaller size, they cannot do better in providing energy than the bigger ones. That is why selection has favored both small and large gametes while the medium-sized ones have disappeared. This process is known as disruptive selection: it favors the extremes of a given trait.

Anisogamy has formed the basis for sexual selection: small gametes compete for the fertilization of large gametes, as the latter are very limited in amount. This has led to male-male competition and the female choice: males, i.e. individuals producing small gametes, try to get their own gametes to fertilize the gametes of the females, i.e. individuals producing large gametes, while females are choosy over whose gametes they want to fertilize theirs - females can produce significantly fewer gametes than males and therefore can't afford to waste them to be fertilized by a low-quality male. 

In case you want to know more about sexual selection, check out this post. If what you want to know is why sexual reproduction exist in the first place, then this is the post you should read next.

[prach025]

10/13

Lab was in the morning, and I basically woke up tired. Cladograms and comparing skeletons and skulls between primates was fun and all, but identifying the traits was a bit difficult since a lot of features were mostly interpretive and hard to distinguish. Lecture was interesting too, but man was it hard to keep up with writing the notes and the speaker. Essentially it was about mating systems in primates (polygyny, monogamy, anisogamy, etc) and traits between male and female and the conflict that arises. Afterwards I went down to the Coffman computer lab and read the readings for the group that presented. Learning about the shopping experience and supermarkets was fascinating to read and ultimately it does get the consumer to follow through with the design of the supermarket.

Spotify: 3 hr 38 min

YouTube: 33 min

[flameinstitutechandigarh]

Assertion : Spirogyra shows anisogamy. Reason : Gametes are identified on the basis of their motility.

Assertion : Spirogyra shows anisogamy. Reason : Gametes are identified on the basis of their motility.

(a)       If both the assertion and the reason are true and the reason is a correct explanation of the assertion (b)       If both the assertion and reason are true but the reason is not a correct explanation of the assertion  (c)        If the assertion is true but the reason is false (d)       If both the assertion and reason are false (e)       If the assertion is false but reason is…

[religion-is-a-mental-illness]

Defining Sex vs Determining Sex - Paradox Institute

https://www.theparadoxinstitute.com/read/defining-sex-vs-determining-sex

Many often conflate two concepts in biology: how sex is defined versus how sex is determined. Conflating these two things, as we will see, can create absurd conclusions, so it is important we separate them out to accurately understand what male and female are and how they develop in the womb.

Defining sex: What are male and female?

Biologically, sex is defined with respect to gamete type. Because there are only two gamete types, there are only two sexes. The male sex is the phenotype that produces small gametes (sperm) and the female sex is the phenotype that produces large gametes (ova). This applies to all species that reproduce through two gametes of differing size (anisogamy), and it includes humans.

Based on this definition, we know whether an individual is male or female by looking at the structures that support the production (gonads) and release (genitalia) of either gamete type. In other words, we look at whether the individual develops a body plan organized around small gametes or large gametes. In humans, sex is binary and immutable. Individuals are either male or female throughout their entire life cycle.

Determining sex: How does an individual become a male or female?

In humans, sex is determined by genes. In biology, determining sex does not mean “observing” or “identifying sex” in the colloquial sense. Instead, determining sex is a technical term for the process by which genes trigger and regulate differentiation down the male or female path in the womb. This determines the structures that can support the production and release of either gamete type, and thus, the individual’s sex.

There are many different sex determination mechanisms across species. Humans and other mammals use genetic sex determination, where certain genes trigger male or female development, whereas reptiles often use temperature sex determination, where certain temperature values trigger male or female development. In all these species, an individual’s sex is defined with respect to gamete type and identified by the structures that support the production and release of either gamete.

Thus, while there are various mechanisms that control male and female development, there are still only two endpoints: male and female.