Extreme Biology

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by Kelsey (AP Biology)

Unity and Diversity is one of the major themes of biology. It explains that even though every living this is unified, there is still so much diversity in the world. It also explains how individuals can be unified, but still diverse, such as a human and a moss.

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Molecular
Every living thing has DNA, deoxyribonucleic acid, which is made up of nucleic acids. Every single strand of DNA no matter what only contains four nucleic acids; adenine, guanine, cytosine, and thymine. Adenine will always pair with thymine, and cytosine will always pair with guanine. This is how every living organism is unified molecularly. However, each strand of DNA has a completely different sequence of these nucleic acids. Different sequences of these nucleic acids will read differently and code for different types of genes. This is how each organism is so vastly different (source).

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Cellular
Every single living is made up of one or more cells. If something has cells, it is considered a living thing. Living organisms are unified because they all have cells. Diversity among these cells is determined by which part of the DNA strand in the cell is read off. This causes cells to be very specific; each one has a specific job or responsibility. An example of this is the diversity found between animal and plant cells. Plant cells have chloroplast to carry out photosynthesis, and a cell wall to contain the chloroplast. Obviously, animals do not perform photosynthesis; therefore their cells lack chloroplast and a cell wall, making them very different from a plant cell (source).

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Organism
Every single organism in the Domain Eukarya has a nucleus and membrane bound organelles. These are called eukaryotic cells; every eukaryote is unified this way. They are diverse because of the different classifications under the Domain. Each organism is separated into different Kingdoms. For example, mosses and humans are both in the Domain Eukarya, they both have eukaryotic cells; however, mosses are in Kingdom Planate, they produce food through photosynthesis, and humans are in Kingdom Animalia, they are heterotrophs (source).

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Every organism in the genus Sistrurus is a pit viper. These are rattlesnakes. They belong to the class pit vipers, which basically mean that they are venomous. They all have a rattler at the end of their tails, and they all give live birth rather than laying eggs. Every species of rattlesnakes share the same diet of rodents and small animals. They are all extremely similar because they are all part of the same genus. However, each species is so diverse that if they interbred, they could not make fertile offspring. There are over fifty different species of rattlesnakes, and each one is vastly different even though they all are in the same genus and share very similar characteristics. For example, the Sidewinder rattlesnake is only 18 inches long. It lives in the desert and only secrets small quantities of venom, while the Eastern Diamondback rattlesnake can kill six human adults with one secretion of venom, and is normally 5 feet long (source).

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Population
A population is defined as organisms of the same species living in the same general area. For example, a bunch of white- bellied spider monkeys living in the same forest. They are all unified because they are the same species and they all live in the same area, but obviously not every single monkey is going to be exactly alike. Their characteristics will differ. Some might have longer hair than others, some might be louder or more playful, some are going to be bigger and some will be smaller. This relates back to molecular unity and diversity. The majority of these monkeys’ entire DNA is the same, but it that little bit that makes them so diverse (source).

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Community
A community is an interaction of organisms of different species sharing an environment. In most communities, relationships called symbiotic relationships are present. This is when two organisms that are different species both benefit from the relationship they’re in. In every symbiotic relationship, the individuals gain something and have to give something. It varies depending on the organism and what each individual needs. Different relationships gain different things, sometimes the organism will gain food and sometime, they will gain a clean body. A bee and a flowering plant have a symbiotic relationship. The bee gains food as it is in the flower, pollen is rubbed on its body, and the flower gains help reproducing and fertilizing. Completely different from that is a cleaner shrimp cleaning a zebra moray eel. The shrimp receives food off of the eel’s body and the eel stays clean and healthy. Each symbiotic is the same, “I’ll scratch your back, you scratch mine,” however each relationship is very different depending on the organisms and what they need (source).

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Biosphere
Every single ecosystem is unified in some way. They all contain the same things, living organisms, and non-living biotic factors. They all interact and every part of the world has ecosystems. The diversity of the ecosystems depends on where they are located, their climate, and what types of factors resonate inside of them. For example, in desert ecosystems, vegetation is scarce because water is scarce. It contains many living organisms, such as cacti, insects, and snakes. It also contains rocks and sand, which are abiotic factors. A rain forest ecosystem is going to be very different because it receives a high amount of precipitation. It also contains insects and snakes, just different species. There are many abiotic factors such as rocks and dirt. They contain a lot of the same families of animals, but they are different because of the climate and location of the ecosystem (source).

This entry was posted on Wednesday, April 30th, 2008 at 5:12 pm and is filed under AP Biology, Themes in Biology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.