Evolution Flashcards
What is evolution
Evolution is the change over time in the proportion of individuals in a population differing in one or more inherited traits.
What happens during evolution
During evolution, changes in allele frequency occur through the non-random processes of natural selection and sexual selection, and the random process of genetic drift.
What does natural selection act on
Natural selection acts on genetic variations in populations.
Do populations produce more offspring than the environment can support
Yes, populations produce more offspring than the environment can support.
Who is more likely to be better suited to their environment, individuals with variations or without variations and why
Individuals with variations that are better suited to their environment tend to survive longer and produce more offspring, breeding to pass on those alleles that confer an advantage to the next generation.
What is sexual selection
Sexual selection is the non-random process involving the selection of alleles that increase the individual’s chances of mating and producing offspring.
What can sexual selection lead to
Sexual selection may lead to sexual dimorphism.
What can selection be caused by
Sexual selection can be due to male-male rivalry and female choice.
How does genetic drift occur
Genetic drift occurs when chance events cause unpredictable fluctuations in allele frequencies from one generation to the next.
In what type of population is genetic drift important
Genetic drift is more important in small populations, as alleles are more likely to be lost from the gene pool.
What is a population bottleneck
Population bottlenecks occur when a population size is reduced for at least one generation, by natural disaster, hunting, or habitat destruction. This leaves a small group of organisms possessing a limited range of alleles.
What makes the founder effect happen
The founder effect occurs through the isolation of a few members of a population from a larger population.
Why is the founder effect important in genetic drift
When a small number of individuals break away from a large population for some random reason it leads to a limited number of alleles being represented in the smaller ‘founder’ population. The gene pool of the new population is not representative of that in the original gene pool.
How is a gene pool altered by genetic drift
A gene pool is altered by genetic drift because certain alleles may be under-represented or over-represented and allele frequencies change.
What is evolution like when selection pressures are strong
When selection pressures are strong, the rate of evolution can be rapid.
What does the Hardy-Weinberg (HW) principle state
The Hardy-Weinberg principle states that, in the absence of evolutionary influences, allele and genotype frequencies in a population will determine whether a change in allele frequencies in a population will remain constant over the generations.
What can the Hardy Weinberg principle be used for
The Hardy-Weinberg principle can be used to determine whether a change in allele frequency is occurring in a population over time.
What does change suggest
Change suggests that evolution is occurring.
What does fitness indicate
Fitness is an indication of an individual’s ability to be successful at surviving and reproducing.
What does fitness refer to
It refers to the contribution made to the gene pool of the next generation by individual genotypes.
What is absolute fitness
Absolute fitness is the ratio between the frequency of individuals of a particular genotype after selection, to those before selection.
What is relative fitness
Relative fitness is the ratio of the number of offspring per individual of a particular genotype to the number of offspring per individual of the most successful genotype.
What is coevolution
Co-evolution is a process by which two or more species evolve in response to the selection pressures imposed by each other.
What acts as a selection pressure on other species
A change in traits of one species acts as a selection pressure on the other species.
Where is coevolution frequently seen
Co-evolution is frequently seen in pairs of species that have symbiotic interactions.
How can coevolutionary relationships be impacted for the individuals involved
The impacts of these relationships can be positive, negative, or neutral for the individuals involved.
What are types of symbiotic interactions
Mutualism, commensalism, and parasitism are types of symbiotic interactions
What does the red queen hypothesis state
The Red Queen hypothesis states that in a co-evolutionary relationship, change in the traits of one species can act as a selection pressure on the other species.
What does the Red Queen Hypothesis mean
This means that species in these relationships must adapt to avoid extinction.
