Directional selection is a type of natural selection that favors one extreme phenotype over the mean or another extreme. Examples of directional selection include giraffes that have long necks and the darkening of London's peppered moths after the Industrial Revolution.
Stabilizing selection, also known as purifying selection, is a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value. An example of stabilizing selection is birth weigh in humans.
Disruptive selection is a type of natural selection that shows a preference toward the reproduction of genetic material at the extremes within a population.One of the most studied examples of disruptive selection is the case of London's peppered moths.
From Wikipedia
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Answer:
500
Explanation:
Mutation rate is largely known as changes that occur in the frequency of a particular gene over an extended period of time
So given that;
the mutation rate of a particular gene = 1 × 10⁻⁶
The expected mutations after 500 million sperm are examined will be:
= (1 × 10⁻⁶)×(500,000,000)
= 500
Thus, The expected mutations = 500
The term used to describe a harmless organism resembling a harmful one is batesian mimicry. Cryptic coloration or camouflage makes prey difficult to spot, while aposematic coloration is a type of coloration exhibited by animals with effective chemical defenses. Mullerian mimicry is a type of mimicry in which two or more unedible species resemble each other.
During metaphase 1, the spindle fibers attach to the centromeres of each chromosome. Both kinetochores of each sister chromatid pair are turned toward the same pole. And 2 members of each chromosome pair (sister chromatids) are pulled into each new cell during anaphase 1.
I think the answer you want is they are called chromatids.
Answer is Middle Paleozoic era.
Paleozoic era was in 542 Ma - 245 Ma and it has 6 periods as Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
360-280 Ma - forming of vascular plants with woody tissues, seeds and veins.
430 - 410 Ma - forming of jawed fishes and first amphibians.
420 Ma - forming of scorpions
360 Ma - forming of crustaceans.
