Descent with Modification
These inherited traits increase an organism’s survival and reproductive success in a specific environment.
What are adaptations?
Although natural selection acts on individuals, this biological level is what actually evolves.
What is a population?
This concept defines a species as populations that can interbreed in nature and produce viable, fertile offspring.
What is the biological species concept?
The evolution of similar traits in unrelated species due to similar environments is called this.
What is convergent evolution?
In a population where the frequency of a recessive allele is 0.1, this is the expected frequency of homozygous recessive individuals under Hardy–Weinberg equilibrium.
What is 0.01 (or q²)?
These remnants of ancestral features provide anatomical evidence for evolution, such as pelvis bones in some snakes.
What are vestigial structures?
A change in the nucleotide sequence of DNA that creates new alleles.
What is a mutation?
Barriers that prevent mating or fertilization from occurring fall under this category.
What are prezygotic barriers?
This process produces new combinations of existing alleles through crossing over, independent assortment, and fertilization.
What is sexual reproduction?
This evolutionary outcome occurs when hybrids are just as fit as parent species, causing reproductive barriers to weaken.
What is fusion?
These anatomical similarities result from common ancestry, even if their functions differ.
What are homologous structures?
In the Hardy–Weinberg equation, this term represents the frequency of heterozygous individuals.
What is 2pq?
This type of speciation occurs when populations are geographically separated and gene flow is interrupted.
What is allopatric speciation?
Apple maggot flies feeding on different host plants are an example of this type of reproductive isolation.
What is habitat isolation?
Aristotle’s idea that species are fixed and arranged in a hierarchy of increasing complexity was known as this.
What is the scala naturae?
This process explains how the environment chooses individuals with favorable inherited traits having more offspring than others.
What is natural selection?
A condition in which a population experiences a drastic reduction in size, leading to loss of genetic variation.
What is the bottleneck effect?
A mule is a classic example of this postzygotic barrier.
What is reduced hybrid fertility?
The random fluctuation of allele frequencies due to chance events, especially in small populations.
What is genetic drift?
The three main mechanisms that directly change allele frequencies in a population.
What are natural selection, genetic drift, and gene flow?
According to Lamarck, organisms evolve through these two mechanisms—now rejected by modern biology.
What are use and disuse and inheritance of acquired characteristics?
This type of selection favors intermediate phenotypes and acts against extremes.
What is stabilizing selection?
The presence of extra sets of chromosomes that can instantly create a new plant species is called this.
What is polyploidy?
When natural selection strengthens prezygotic barriers because hybrids are less fit, this process occurs.
What is reinforcement?
Name the five criteria that must be met for a population to be in Hardy-Weinberg Equilibrium.
1. No mutations
2. No gene flow/migration
3. No natural selection
4. Large population
5. Random mating