Change in population through natural selection

In a single-gene, traits can lead to changes in allele frequencies and, thus, to changes in phenotype frequencies. It also causes evolutionary, but not all the time. Evolution does not require natural selection.

Natural selection affected elephants by making them cool down. Elephants don't have the glands that keep them cool. But by natural selection, they are able to live in 80 degree weather.

Polygenic traits in animals include weaning weight, weight, hair color and length. Behavioral characteristics of animals are often controlled by multiple gene loci as well, although the environment, in the form of parental care, often influences behavior as well. On polygenic traits, natural selection can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.

The evolution of the peppered moth is an evolutionary instance of colour variation in the moth population as a consequence of the Industrial Revolution. This caused natural selection to cause an increase in the number of dark-coloured moths. Due to industrial pollution and a reciprocal decrease in the population in a clean environment, its has cause the moths to become more darker colors than lighter colors.

Natural selection has caused robins to lay 4 eggs about every time. The ones who lay more or less than 4 will most likely result in malnourished or overnourished chicks. The robins that lay 4 eggs will have the best change for their chicks to survive.

In a habitat there are red bugs and green bugs. The birds prefer the taste of the red bugs, so soon there are many green bugs and few red bugs. Natural selection causes the green bugs reproduce and make more green bugs and eventually there are no more red bugs.

Bunnies are affected by natural selection. Natural selection can use microevolution to change alleles frequencies, with fitness-increasing alleles becoming more common in the population. Natural selection can also act on traits determined by alternative alleles of a single gene, or on polygenic traits. Natural selection has caused some bunnies to be white and others to be brown. The ones who are white have a less likely chance of surviving due to their white coat. Predators can see the white fur and have a harder time seeing the brown fur.


Created with images by davidshort - "Green shieldbug (BG)"

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