Biology Questions
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Structures in modern species that have the same function, but are not inherited from a common ancestor
A population bottleneck occurs when the size of a population is greatly reduced for one or more generations. Because the population size is smaller, the surviving population is much less likely to have all of the alleles the larger population had before the bottleneck and will likely have less genetic diversity.
The environment determines which phenotypes are favorable. If an environment changes, or if individuals move to a new environment, natural selection may result in different phenotypes being favored.
Instead of the environment selecting for individuals with favorable phenotypes, humans select which individuals will survive and reproduce.
The founder effect occurs when a few members of a larger population start a new population. These few members of the larger population often have less genetic diversity compared to the larger population or may be a nonrandom sample of the population, changing the allele frequencies.
p^2 + 2pq + q^2 = 1 where p^2 is the frequency of the homozygous dominant genotype, 2pq is the frequency of the heterozygous genotype, and q^2 is the frequency of the homozygous recessive genotype.
the transfer of alleles from one population to another
Selection that occurs when humans selectively breed domesticated plants and animals to produce phenotypes with desired traits.
all of the alleles at all loci in all members of a population
the reproductive success of an individual in a population
- Variation in populations leads to different phenotypes in a population- Competition for limited resources or predation leads some members of the population to survive while others do not- individuals with phenotypes that give them a survival advantage in a particular environment are more likely to survive and reproduce. - Over time, favorable phenotypes will become more prevalent in a population as members of the population without those favorable phenotypes do not survive
- diploidy means that recessive alleles are hidden from selection in heterozygotes - the heterozygote advantage occurs when heterozygous individuals at a particular gene locus have a survival advantage and keeps the mutant allele relatively common
Species that live in similar environments may evolve similar adaptations even they may not have a recent common ancestor, such as how sharks (fish) and dolphins (mammals) evolved similar body shapes.
Sexual selection occurs when individuals with certain characteristics are more likely to attract mates than other individuals. Over time, individuals with traits that are more likely to attract mates become more prevalent in the population.
Comparison of early stages of animal development reveal many conserved anatomical structures in embryos that are not visible in adult organisms. For example, all vertebrate embryos have a post-anal tail and pharyngeal pouches
the history of the evolution of a species or group
A type of selection where individuals on both extremes of the phenotypic range are more likely to survive and reproduce than individuals with an intermediate phenotype. An example of this is rock pocket mice living on sand and volcanic rock, where an intermediate-colored mouse would be unfavorable on either environment.
Natural selection results in alleles being passed to the next generation in proportions different from their relative frequencies in the present generation, as individuals with variations better suited to their environment tend to survive and produce more offspring.
mutations are random and create genetic variation, but natural selection acts on those phenotypes and is not a random process
populations evolve when some members of a population have greater reproductive success than other members of the population