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ECOLOGY

Ecology is all about understanding the relation of the biotic and abiotic environment. As an example of this we have the homosapiens that on the primitive society had the necessity to get to know the animals, the plants or other types of foood, understand the weather to deal with the shelter, etc. The main response to what’s ecology is the interaction between the organism with each other and it’s enviroment, and how it does affect both of them. 

Many people befuddles the concept Ecology and Environmentalism. To explain it, it all started in the modern society, more specifically in the Industrial Revolution where they started using the “services” of nature creating another things, devaluing then the nature itself. So this by ecology they got to environmentalism to take care of the nature. 

So, ecology can go all the way about it. To a more purposefully understanding, ecology gets to know the location and abundance of the organism related to the the other organism and how does the abiotic environment influence it. The ecological sytem works in many levels, just like a system, connecting to each other. First, we start with an organism (formed by atoms that forms molecules and them cells and all the other things), by these one we get others and they’ll live as a population. Then we get to the comunity, formed by different organisms living together in the same space, and when we join the abiotic environment, where they’re living with the air, water, minerals, etc. 

To many of these organism may survive, they need to “evolve” to live in the environment where they found. This evolution is already in their systems, the environment does not influence their physiology, morphology or their behavior. As an example, the theory of species, where the “better” ones survive: A frog who’s changed it’s color to green won’t be seen in the trees by the predators.

From the copulation of these organisms, comes the population which is nothing more than the same species living in the same environment. Since they’re way much more than a simple organism, we can see properly the abundance of the specie, where you can find more of them, etc. 

Now, a comunity is formed by different populations of species coexisting in the same place. It may be a ‘rich’ environment depending on the abundance of the different organisms and how many different ones are there forming it’s diversity.

The Ecosystem is the interaction between one or more comunities with the abiotic environment - the accumulation and transfer of energy between one another. We can see the organism as some kind of energy, “an energy coin”.

Biosphere refers to all the ecosystem on Earth

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We can classify the organisms in 5 groups:

The autotrophic: organisms that uses photosynthesis to convert solar energy in organic compounds or the ones that uses chemosynthesis to convert chemical energy in organic compounds. Let’s show an example: The solar energy will reflect in the plant, more specifically on the leaf. It’ll be absorbed and converted in metabolism and biomass (growth). The metabolism will be the energy consumed so the plant can survive. 

The heterotrophic: they obtain the energy of others organisms. In this class we have three different types: the consumers (animals) that ingests organic matter that’s either alive or has been recently killed. The detritivores that ingests non-living matter, like vulture and hyena. The saprotrophs that also ingests non-living matter but they secrete digestive enzymes into the dead organic matter and then digest it externally absorbing the products. Example of how the heterotrophic mode of nutrition works: Let’s suppose a random animal (herbivore) eats a plant, it’ll help the metabolism to make the organism live well, and then it will defecate and maybe some other animal like the  Digitonthophagus gazella (a detritivore) will use it as it’s own “food”. The food that the other animal ate will give him biomass (production), helping it reproduce better.

EVOLUTION

Why are there so many different organisms and such diversity in it’s species? 

According to Darwin and Wallace, the species has the tendency to form varieties. It may occur from our own interference, the artificial selection: Like creating hybrids of dogs, different flowers, stronger animals, variety of cereals etc. So, they got to the result that the variety of species was an outcome of an evolutionary process that was favored by the natural selection, the one who gets to stay.

The natural selection - Let’s imagine: The organism diversify in their attributes, and these attributes are genetically passed to it’s descendants. These variations may make these organisms “better”, making them survive and reproduce faster, creating another specie with this gene. 

The process that creates another specie is called speciation, this term is created to refer to the cladogenesis oposing to the evolution based on the anagenesis. Cladogenesis brings about the reproductive isolation, it may be the allopatric isolation whereas it’s about geographic isolation: a physical barrier that stops the reproduction between the organisms that belonged to the same population. These organism will create different mutations than the others on the other side of the barrier.The parapatric speciation presents no barrier, meanwhile there’s a partial spatial isolation though the population doesn’t copulate randomly. They’re more likely to mate with the ones closer. Now, the sympatric speciation occurs when there’s an isolation between the population, generally there’s already an inicial reproductive isolation.

Just as the organism varies, so do the environment -> The distributionof the population varies depending on the environment

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Plant Tissue

It all starts with the meristematic tissue, formed by identical cells divided by mitosis. They begin growing through the root of the plant, being protected by the coif that are formed by parenchymatic cells that function as backfilling. On exception of the pteridophytes (they don’t have seeds), the root will growl of the sporophyte, and the other ones will growl out of the radicle of the seed. The plant will growl through the meristematical zone and create axial, apical meristem, etc, that’ll form roots, twigs or stalk. They’ll continue growing since they’re made of meristimatic tissue. 

The meristimatic tissue is divided in primary and secundary, the primary focus on the vertical growing and the other on the horizontal. 

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Cell Division

The cells are constantly dividing, that’s why our wounds heal (not in case of a diabetic perso, that’ll explain later on) “ When organisms grow, it isn't because cells are getting larger. Organisms grow because cells are dividing to produce more and more cells.” Most of the times, when we’re talking about it comes to mitosis, creating two identical cells, as an example: the meristem that keeps on growing on the plants. But there’s also the meiosis who’s focus is on the sex cells, “ like female egg cells or male sperm cells “, it’s because of the them that we have genetic diversity. “ Genetic recombination is the reason full siblings made from egg and sperm cells from the same two parents can look very different from one another”

MITOSIS 

These are the somatic cells that makes up the most part of our body, like our skin, muscles, lungs, hair cells, etc. That’s why they’re able to reproduce all over again. (Remember Plantae and their reproduction). The cells that reproduce through mitosis are non-reproductive cells, which means they undergo asexual reproduction. They create the same cells, just like copies. 

MEIOSIS

Creates sex cells, female eggs or male sperm. In each new cell contains a unique set of genetic information, when these two sex cells join they create a unique organism. 

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Reino Plantae

A planta teve sua origem na água, provavelmente das algas verdes que são provenientes de cianobactérias. Para chegar ao meio terrestre elas sofreram diversas modificações, já que na água oferecia gases e materiais e tinham um meio de reprodução fácil pelos gametas móveis, além de ser um meio de sustentação para estas, pelo empuxo exercido. Um “resquício” dessa evolução pode ser vista nas briófitas, que até hoje precisam da água para sua reprodução. 

Dentre as modificações necessárias para que as plantas chegassem ao meio terrestre foram necessários variadas adaptações: Um meio de absorver a água do solo, como a raiz; Tecidos necessários para a condução da água até as células mais distantes, como o xilema e o floema (tecido de condução adulto); Impermeabilidade para evitar a perda de água, dada pela parede celular que reveste a membrana; Tecidos adultos para sustentação do corpo e tecidos que permitem a troca gasosa para facilitar a fotossíntese, como a epiderme com os funcionais estômatos.

A planta originalmente é formada pelo tecido meristemático, o tecido embrionário, formado por células iguais que se dividem por mitose continuamente, que posteriormente formam outros tecidos “adultos” com suas devidas funções. Primeiramente, o meristema começa na raiz da planta, chamado de meristema radicular. Este é protegido pela coifa, células parenquimáticas (tecido de preenchimento). Esse meristema radicular fica na zona de multiplicação celular e quando vai vai crescendo na zona de distensão da raiz, as células vão sendo empurradas para a ponta. Na raiz há também a zona pilífera, parte da raiz que absorve água e nutrientes minerais, e mais acima tem a zona suberosa que são novas raízes provenientes da principal. Além disso, existem os mais variados tipos de raízes com diferentes funções, classificando-as em subterrâneas, aéreas e aquáticas.

Em pteridófitas, já que não possuem sementes, a raiz se desenvolve a partir do esporófito, e em vegetais com sementes (espermatófitas - parte das traqueófitas (plantas vasculares)) a raiz vem da radícula da semente. A raiz pode tomar formas diferentes nas angiospermas (monocotiledôneas e dicotiledôneas).

Diferença de raiz e tecido de condução:

Do caulículo do embrião, surge o caule,que assim como as raízes tem suas diferenciações, podendo ser aéreo ou rizomas (caule subterrâneo), dão origem as gemas axilares que são dotadas de tecido meristemático, criando novos ramos, caules, folhas ou flores. Faz papel de fotossintetizante em plantas desprovidas de folhas, como o cacto, e também em jovens vegetais. E graças as gemas laterais/axilares, origina-se a folha, que faz a fotossíntese (em outras podem ter funções especializadas). As nervuras da folha mudam conforme dicotiledônea e nas mono. *Gema apical foca no crescimento vertical, na altura. Foca no desenvolvimento do caule. Gema axilar ou lateral são as gemas de crescimento horizontal, formando novos ramos na planta.

                                                 TECIDOS

Na foto, podemos ver a ponta de uma raiz com seus tecidos de meristema primário, são os tecidos que focam na altura da planta, que originam os outros tecidos adultos. Na parte amarela temos a protoderme, que originara a epiderme. No meio, onde mostra o procâmbio, seria o xilema e o floema primário, que dará início ao tecido de condução. 

Nessa imagem, temos o meristema fundamental que é parte do meristema primário, ele dará origem a alguns tecidos adultos, como o de preenchimento, que o tecido parenquimático e aos tecidos de sustentação como a colênquima e a esclerênquima.

O meristema secundário é focado na espessura, estes são o câmbio/felogênio que dá origem a súber, este divide-se, sendo para o meio exterior o súber e o interior a feloderma. Essa junção forma um tecido de revestimento chamado Periderme. As células do felema (súber) são células mortas “devido à impregnação de grossas camadas de suberina (material lipídico) nas paredes da célula, deixando-a oca”. Como essas células formam uma barreira para a troca de água e gases do ambiente, é necessário meios que ajudem a troca para o meio mais interno, por isso há as lenticelas, que são porções da periderme com grande espaço intracelular. São áreas “salientes” nos caules e raízes. Outra parte da súber são os ritidomas, porções mais velhas das células, marcando a casca.

MERISTEMA PRIMÁRIO: Protoderme -> Epiderme; Procâmbio - Xilema e Floema primários. MERISTEMA SECUNDÁRIO: Câmbio e Felogênio -> Xilema e Floema secundários e Súber. FUNÇÕES - TECIDOS ADULTOS: Epiderme e Periderme -> Revestimento; Preenchimento -> Parênquima; Sustentação -> Colênquima e Esclerênquima; Condução -> Xilema e Floema.

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Cellular Transport

How does the substances move through the cell? 

First things first, that's the main role of the membrane. They have their mechanisms of transportation: Simple Transportation - The hydrophobic substances just go directly into the membrane, being absorbed by the lipids. This is called Simple Diffusion, whereas the molecules pass right through the membrane commanded by the Concentration Gradient. The other one, Facilitated Diffusion, needs especific proteins to pass the molecules to the other side, and they can be hydrophilic too, because they won't get in contact with the hydrophilic part. These proteins are the Carrier Protein, they're not always open, they're sometimes closed. And there's also the Channel Protein that can pass a lot more substances faster at the same time. We also have the Active Transport - this one uses energy to move the molecules, and works on the contrary of the Concentration Gradient, moving the molecules to where it has more molecules already. They use an energetic protein, also called as pumps, the ATP, that lately is "hydrolyzed”  in ADP + phosphatus, being free to "pump" ions or other solutes through the membrane.

*The ATP/ADP explanation:

*Difference between the Protein Channel and the Carrier Protein: The Channel Protein works best for ions, and the Carrier Protein for molecules, also the first of is always open and the other changes it’s shape for the molecule.

Solid substances - when a larger substance is trying to pass through the cell, like a bacteria for example, in this case there happens other types of active transport, “through vesicles or other bodies” the “thing” pass on the cytoplasm, these are the Endocytosis, divided in phagocytosis and pynocitosis and the Exocytosis, where in order to release the contents out of the cell, “the vesicles fuse with me plasma membrane”, “occurs in case a cell produces substances like proteins or try to get rid of the toxins that’ve been phagocytosided.  Phagocytosis is allso called “cell eating”, but the process of feeding is more likely to other cells, the human cell when it comes to phagocytosis is linked to the acted of defeating from something. The plasma membrane forms pseudopods that engulfs the particle, forming a “phagocytic vesicle”. In the Pynocitosis, these substances are dissolved, so the plasma membrane forms a “channel” so it can enter, when the channel closes it forms a “pynocitic vesicle”.

*ATP and ADP

Now, how do water get into the cells? 

Through Osmosis, that works just like diffusion. Depending on how much water the enviroment has the cell gets in different shapes. If it’s found in a hypertonic way, which means a lower concentration of water, the cell will me plasmolized trying to give water to the place where it's found. In a hypotonic way, the cell is fulled ‘til it gets isotonic, which means the ambient and the cell are equal in water. But to that happen, the cell generally needs a cell wall (rigid), like the plants and bacterias, in other cells it’ll most likely to burst. In plants, you can see how the hypotonic osmosis work, the cell gets full and won’t burst because of the turgor pressure. “This is actually good for the plants since if it’s hypertonic or isotonic the cell will keep losing water, and in case of the hypertonic, the cell will plasmolize.”

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CHONSP

Ever wondered about your chemical composition? Remember always that we’re firstly atoms, and from atoms we get the molecules (organic and inorganic) that makes our whole body function. 

So, basically we are made of Carbon, Oxygen, Hydrogen, Nitrogen, Phosphorus and Sulfur. An example of one of these molecules (that I already told before, I know) is the H20, 70% of what composes our body.

Here we can see the molecule, formed by two atoms of hydrogen and one of oxygen. Water works also as our solvent, though it only dissolves polar solvent since it’s a covalent bond, which means it’s a neutral molecule (there’s no gain or lost of eletrons), that’s why the oil (lipids basically) doesn’t “get together” with the water, the molecules of oil.

                        THE INORGANIC COMPOUNDS

“Generally, the inorganic compounds are those ones whose doesn’t have a carbon atom in it’s structure/molecule. Like water and mineral salts, that can be found in two types in the organism, as dissolved ions (atoms that got more or lost it’s eletrons) and also it works regulating the enzymatic activity, bonding to proteins or others.” Below, there’s a good example of how these mineral salts work, “the potassium and sodium auxiliates balancing the osmosis and the conduction of the nervous impulsion through the neurones (basic structural cell of the nervous system). ”

                          THE ORGANIC COMPOUNDS 

The organic compounds are complex and “and mostly full of energy”. These are formed by carbohydrates, lipids, proteins, vitamins and nucleic acid. 

Carbohydrates (glucids) - they have a role as an energetic fountain and participate on formation of some structures. They give quick energy and are absorbed fast. It’s divided in three groups:

monossacharides - the real sugar and more simple than the others.  The amount of Carbon varies between at least three or eight. Glucose, Fructose, Galactose. Also they create one important part of the RNA and DNA, Ribose and Deoxyribose.

disaccharide - one of the most important oligosaccharide, formed by two or more monossacharides, like the Sucrose (Glucose+Fructose) or Lactose (Glucose-Galactose).

polysaccharides - constituted by the union of a bunch of monossacharides, they’re not soluble on water like the others and don’t have sweet flavor either. The most important ones are the Cellulose (the cell wall of a vegetable), Glycogen (works just like the Starch on plants, but they’re in animals) and Starch (the reserve of energy of the plant).

Lipids - “organic compound unsoluble on water and soluble on alcohol or ether”. It gives even more energy than the Carbs and also function as a thermal insulator on some animals, ex: sealion. There are a lot of types of lipids, such as oil and fat, wax, phospholipids (the most part of the plastic membrane), steroids (hormones). Also, there’s the cholesterol that’s transported by a protein, divided in two types HDL (the good one), LDL (the bad one), that’s because the good one transports the cholesterol from the arteries to the liver, where’s it’s inactivated and the bad one transports from the liver to all other cell tissues and also to the arteries, acumulating in it’s walls or veins, conducting to an AVC.

Vitamins - “generally not produced on our system, but obtained through food”.

Proteins - formed by amino acids. “the human being uses around twenty amino acids to constructe a lot of different proteins”. they’re also part of the membrane plasma and the organeles that have membrane and a lot of other things in the organism that’s fundamental to grow up. “To produce more cells, you need more proteins”. Within their types, there are those important ones antibodies, some hormones, enzymes that helps to differ and produce the chemical reactions, acting as catalyst. 

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How does the cell works?

The cells are part of all those who are alive (I’ll make an article about viruses another time). It’s what composes us, every part of it. The organelles in it work just like as fabric, to keep it all working. The organisms can be differed by their quantity of cells, those who are unicellular (algae, bacteria, protozoan, some fungae and the archaens) and the multicellular (just like us and the plants). An important reminder, is that we have different cells in our body to perfom every function required to keep working, like the muscle ones that makes us move and those on the intestine that absorbs the nutrients. 

                                          THE EUKARYOTIC

Each of these organelles work in different ways to make the cell function well. All of them are kept in the cytoplasm, which is composed by cytosol, a viscous fluid basicly made of water, ions and also substances like carbs, enzyme, protein and salts). The amount of water on it allows substances to move and provide a better enviroment to quimical reactions, also the deslocation of the organelles.

                         The organelles and their functions

Nucleus - Keeps the DNA, controlling the hereditary traits of an organism. Works as the central control of the cell. Inside of it we have the nucleolus, this one helps on the production of RNA (a molecule that manages on the synthesis of protein). In the middle of this two, we have the chromatin, which is basically the DNA plus the histones (proteines), they contain the genetic information. And to finish, this is all enveloped by the cariotheca, which is almost the same as the plasma membrane, it also has some holes on it to control the “in and out” of substances on the cytoplasm.

Plasma membrane - It envelop the cell and controll what comes in and out = It has a function of selective permeability.  Through the Fluid Mosaic Model, it shows that the plasma membrane is formed by a phospholipid bilayer, the one that’s given the power of the selective permeability, and those proteins (whose keep moving thanks to the fluid e oil consistency of the plasma) that got a lot of functions, mostly the transportation of substances in and out of the cell.

Mitochondrion - They’re responsible for the cellular respiration, and because of this process they create a lot of ATP (provides energy to many process in the cells). There’s a theory that the mitochondrion was initially a bacteria that was engulfed through phagocytosis creating the organalle on the eukaryotic cell.

Ribossomes - They fabricate protein by using their RNA and amino acids (molecules connected by peptide-bonds (CHONPS)). It can be shown free on the hyaloplasm or attached to the endoplasmatic reticulum (forming the rough one).

Lysosome - It digestes some particles phagocyted by certain cells, such as lipids, carbs, protein and nucleic acid (DNA or RNA). It’s known that they come from the Golgy body, and their digestive substances have been formed in the Rough endoplasmatic reticulum. They also destroy the non-utilitarian cell matter. Here’s an example of how this works: In the white blood cells, whenever there’s an invasion of microrganisms, the cell emits the pseudopods (again, thanks to the cytoplasm whom gets to be deformed because of their consistency) and phagocytes the bacteria. Then the lysosomes comes and merge with this food vacuole, liberating their enzyme (proteins “ that act as biological catalysts “), this fusion forms the digestive vacuole (secundary lysosome), with this, it finally happens the klasmakytos, when the cell eliminates the particles they don’t use. 

Cytoskeleton - It’s the protein filaments on the cell, a “dynamic network”. They’re important to keep the cell steady, since we don’t have a cellulosic wall like the plants do. By the way, the pseudopods can only be formed because of the actin filaments of the cytoskeleton. It’s also used to deslocate the substances through the microtubules (a thicker filament).

Endoplasmatic reticulum - They may present changes in their shape (on the cells of a plant the endoplasmatic reticulum coincide with the vacuole). Their substances circulate through it and it may accumulate in one local. The smooth one produces lipids that composes the plasma membrane, some hormones, osmotic regulation (takes substances out of the hyaloplasm, changing the internal concentration in the cell, favoring the osmosis), like the vacuole, it stores substances. Also, it transforms toxic substances (ex: meds, alcohol) in non-toxic. Usually, people who abuses of this toxic things have a bigger reticulum than the others. The rough one got a bunch of ribossomes attached to their membranes, that makes the ER isolate and transportate the proteins that were built inside it.

Golgi body - The main function of this organelle is to modify the lipids and proteins that comes from the ER. The protein that comes from the rough ER are transferred to the Golgi body, then they’re identified or transformed. They can be inside the cells, just like the lysosome or turn into a secretion vesicle and then they are liberate as digestive enzymes.

Peroxisome - Capacity of producing hydrogen peroxity, they’re capable of neutralizing the effects of  O2.

THE PROKARYOTE CELL is the cell that makes a bacteria, archea and cyanobacteria. Although we are made of eukaryotic cells, we have some prokaryotic ones inside of us (meaning those living things said before). Just like the other type of cell, they have cytoplasm, plasma membrane, ribosomes and DNA. They lack a nucleus and the other organelles, so their DNA is found in the nucleoid. Besides the plasma membrane, there’s the cell wall to keep them in shape, and many  bacterias also have the capsule that “helps ‘em attach surfaces in the enviroment”. The fimbriea is made to connect to the mucosas of the organism, the sexual fimbriea serves for attaching the bacterias to exchange DNA and is also known as the Pilus/pili (another hair-like). Now, the primary function of the flagellum is moving the cell (as we can see like in the sperm cell). The plasmid are DNA molecules that can be shared through bacteria to bacteria, carrying around the genetic material and maybe new genes. That’s how they get more resistent.

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Who are we?

                      ATOM - THE BASIS OF EVERYTHING

The atom, formed by particles such as protons (+) and neutrons whose form the nucleus, and there’s also electrons (-) orbitating around it. It’s considered the smallest unit that forms a chemical element, leading to the creation of the matter. 

                         How does one matter is formed? 

Given the “reunion” of the atoms, we have the molecules. Those particles are composed from same or different atoms. That’s what forms all substances, as an example, we have the molecules from the water (H2O), these are done by two atoms of hydrogen and one oxygen atom. By all different kinds of atoms are established a whole bunch of types of chemical molecules, forming everything we are surrounded with. 

                                 The biotic enviroment*

This is an example of an animal cell, this is what we are made of. To start off, the organelles are created through the molecules, each of them have a function to make the whole cell work, they all together will form the cell itself. 

This one is a prokaryote cell, the one who makes the bacterias and cyanobacterias (a type of bacteria that looks like algae). It’s known that they’re probably originated the eukaryote cell (theory of endosymbiosis). They differ from the other because they don’t have a nucleus and the other organelles, apart from the ribosomes. 

This one picture shows us the virus, one big great question that surrounds us, is this agents alive or not? Though they’re acellular, it’s still capable of evolving. There are theories around it, supposedly it may have evolved from a bacteria or plasmids. Viruses have genetic material and it’s body is wrapped in protein. To live, it needs to find an enviroment (other cells) where it can obtain their own metabolism. When it’s inside a cell, it’ll finally be able to reproduce their RNA, modifying the cell’s metabolism. 

                                       And then what?

Explaining it in a simple and short way of how to form an organism, the cells will get together and form the tissues (different tipes), and with a set of tissue, it’s formed the organs, those organs working together make a system. That all together, we have an organism, such as a human being, a leopard or a plant (there are some differences in the formation on those species and their components, but it goes on the same scheme).