by Erica Jar

Definition of Adaptations

2013-07-29 22:32:08 UTC

The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to their environment.

2013-07-29 22:32:45 UTC

When the environment changes an organism must either change, leave or die. The changes are selected for on the basis of variation in genes between organisms in response to environmental change.

Adaptations of a Kiwi

2016-08-04 01:26:06 UTC

- Nostrils at end of the beak which enables it to search for food by probing its long beak into the earth.
- Whiskers to aid them in nocturnal navigation as they have poor eyesight.
- Loss of the ability to fly. After many years of not requiring the use of flight, they evolved a larger body size and lost the ability to fly.
- Feather color and pattern to camouflage them in the wild.
- Large gape/mouth opening to allow for easy digestion of fruits seeds etc.
- Powerful legs and sharp claws to dig for food, burrowing or for defense.
- Hair like feathers to provide warmth.
- Highly developed sense of smell.
- Large ear openings for a good sense of hearing.
- Fleshy foot pads to tread softly and catch prey by surprise.
- The kiwi is nocturnal which helps to reduce its risk of predation and competition for food during daylight.

Sources of genetic variation of a gene pool.

2016-08-04 01:27:20 UTC

Sources that affect genetic variation in a gene pool are:
Natural Selection
Genetic Drift
Bottleneck effect
Founder effect

A gene pool is the complete set of alleles in a population.

The gene pool changes in allele frequencies due to random events not related to the fitness of the allele relative to that environment.

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in heritable traits of a population over time.

Genetic drift is the change in the relative frequency in which an allele occurs in a population due to random sampling and chance.

Migration is the transfer of alleles of genes from one population to another.
The effects of both genetic drift and migration are particularly apparent in a small population where the relatively small changes in allele numbers can have a bigger impact on the ratio of those alleles in the population.

Natural Selection

2016-08-04 01:29:51 UTC

Definition: the process where organisms better adapted to their environment tend to survive and produce more offspring. The advantageous trait allows the organism to have more offspring and become more common in the population. Eg: green beetles tend to get eaten by birds more than brown beetles, therefore, not all green beetles get to reproduce to their full potential and eventually brown beetles become more common.

This links to fitness cost - as the organisms that breed less do not pass on less advantageous genes (for that environment) which mean that in event of a major catastrophic event there is less genetic variation for survival of the species.

Fitness

2016-08-04 01:29:52 UTC

Biological fitness also known as Darwinian fitness.
The ability to survive to reproductive age, mate and produce offspring.
Produce more children = more fitness.
"Given that differences in survival and number of offspring produced depend mainly on an individual's DNA, biological fitness is usually discussed in terms of most and least successful genes, or characteristics." http://study.com/academy/lesson/biological-fitness-definition-lesson-quiz.html
Usually discussed in terms of genotype fitness. genotype fitness is average fitness of all individuals in a population of that specific genotype.

"Frequently in this column, the phenomenon of fitness cost has been discussed. This is when an organism, as it undergoes minor changes in reaction to changes in its environment, improves in one area of its abilities but pays a price by becoming less fit in another area"
IE: When one gene is selected for in an environment, another is lost
http://www.biblearchaeology.org/post/2011/06/06/Rapid-Microevolution-and-Fitness-Cost.aspx

This relates to adaptations because as an organism becomes more adapted to its specific niche it loses the genes required for different niches, reducing the chance of survival in event of a major catastrophic

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