Sierra College Department of Biological Sciences

Discover the Biological Sciences

The introductory information for this site has been contributed as a joint assignment by students in Bio. Sci. 10.

Evolution - Natural Selection

By: Larisa Glushko

1) Biological field or sub-topic chosen:

Natural Selection

Define field or sub-topic:

Natural Selection – process which individual organism who safety at time only reserve over successive generations. At time safe only that, which success survive himself at time. Also a Natural selection and the adaptive evolution it causes are observable phenomena. Natural selection within the bounds of the single generation is an active factor in biology.

Describe in more detail the breath and depth of what could be studied or learned within this topic:

Natural selection learned is most determined to operate on heritable term, but can sometimes refer to the various reproductive success of phenotypes regardless of whether those phenotypes are heritable. Natural selection acts on the phenotype, or the observable characteristics of an organism, such that individuals with favorable phenotypes are more likely to survive and reproduce than those with less favorable phenotypes. If these phenotypes have a genetic basis, then the genotype associated with the favorable phenotype will increase in frequency in the next generation. Natural Selection is process can result in adaptations that specialize organisms for particular ecological niches and may eventually result in the emergence of new species.

For Natural Selection to occur two requirements:

Heritable variation (beak size, color pattern, fleetness, and thickness of skin).

Differential survival and reproduction associated with the possession of that train.

For examples:

If some plants grow taller than others and so are better able to avoid shading by others, they will produce more off spring.

If some individual are fleeter than others because of differences in their genes, but the predator is so much faster that it does not matler, then no evolution will occur.

In addition, natural selection can only choose among existing varieties in a population.

4) Focusing on one major concept, principle, or group of organisms (as appropriate within the topic), describe its importance, relationships, functional aspects, or otherwise explain it in more depth as seems important to you and (potentially) the others in class:

I think one of the most important of natural selection is adaptation. Adaptation are structures of behaviors that allow efficient use of the environment. For example, the webbed foot of a duch enables it to swim better than a foot that is not webbed (chicken).

Many options of organisms that are adapted:

Air, food, water, animals, human...

Most common form of adaptation is acclimatization. Acclimatization common the organism. To go through in a new environment.

«Precisely similar considerations apply to all other cases of adaptation. For instance, elementary observation shows a correlation between the prevailing color and pattern of animals and that of their environment. This provides a prime facile case for the relation being an adaptive one. But this deduction is a first approximation only. The next step is to make detailed ecological observations on particular cases; to see whether alternative explanations may not be preferable (such as the view that there is a direct effect of the color of the environment on the organism, or an indirect effect via the prevail in climate), and , where possible, to check the adaptive value by experiment. We shall then be able to reject a certain number of suggestions that the pink color of flamingos enables the to escape detection against the sunset sky, and to retain a certain body of firmly established fact and a considerable residuum of high probability.» - Evolution The Modern Synthesis by Julian Huxley.

In studying and discovering more about this topic, what was the most interesting aspect, fact or some other piece of information that you have learned.
The most interesting aspect then I was learned of natural selection is adaptations because I studied a lot of useful and important events.

References – provide references used and at least two Web sites with additional information on this topic (or sub-topic) for anyone that would like to learn more: <> , <> <> , <>

and Evolution The Modern Synthesis by Julian Huxley.

(return to the "Discover the Biological Sciences" main index page)

W3C Logo: Valid HTML 4.01 Transitional W3C Logo: Valid CSS