Unit 6 - Population Genetics & Evolution Flashcards
What is Gene Flow?
Gene Flow(aka gene migration) is when genes are transfered from one population to another. Immigration and emigration are responsible for this.
What is a Gene Pool?
A gene pool is the set of all genes in any population of a certain species. A large gene pool signifies a lot of genetic diversity.
What is Genetic Drift?
Genetic drift is the change in the frequency of an allele in a population.
What is Genetic Variation and how is it caused?
Genetic Variation is the diversity in gene frequencies in a gene pool. At a population level, genetic variation can be identified by observing phenotypic variation. Genetic Variation can also occur between populations, which occurs because of geographic variation. Genetic Variation is caused by random mutations.
How are genotype and phenotype different?
Genotype refers to the alleles an individual posesses, whereas phenotype is the physical trait that is expressed because of the genotype.
What is Gradualism?
Gradualism is the evolutionary belief that change happens gradually instead of suddenly. This theory was proposed by James Hutton in 1795 and influenced Darwins evolutionary ideas.
What is a Habitat?
A habitat is an area that is inhabited by a specific species of organism. This is made up of biotic(living) and abiotic(non-living) factors.
What are the two H-W Equations and what do the variables stand for?
The two equations are: p + q = 1 and p^2 + 2pq + q^2 = 1. p stands for the frequency of the dominant allele, while q stands for the frequency of the recessive allele.
What is a heterotroph and what is the opposite?
Heterotrophs are organisms that feed on other organisms to survive. The opposite of a heterotroph is an autotroph, an organism that can make energy using basic energy such as sunlight.
What are homologous structures? Give an example.
Homologous structures are the existence of shared ancestry between different species. For example the wings of bats, the arms of primates, and the flippers of a whale all contain similar bones, although they are all different shapes and sizes.
What is a hybrid? Give an example.
A hybrid is a mix of two diferent species. An example is a mule, a cross between a female horse and a male donkey. Mules are infertile, meaning they cannot produce offspring because they have 63 chromosomes, a mixture of horse(64 chromosomes) and donkey(62 chromosomes).
What is logistic growth and when does it occur?
Logistic growth is an “S” shaped curve that grows exponentially for a time then slows and approaches a carrying capacity. The equation for this is: dP/dt = rP(1-(P/K)) in which P is the population size, t is time, and K is carrying capacity.
What is the primordial environment?
The primordial environment was the environment in which life first began which had a different atmosphere and landscape. There was far less oxygen in the atmosphere and volcanic activity as well as meteor impacts were common.
What is punctuated equillibrium?
A long period in the fossil record where a species undergoes very little morphological change and is interrupted by brief sudden changes
What is random mating and why is it significant?
Random mating is one of the conditions for the Hardy-Weinberg Equilibrium where individuals do not mate preferentially so that genotype frequencies stay the same
What is sexual selection?
Selection of individuals with certain inherited characteristics that make them more likely to obtain mates and reproduce
What is a species?
Populations whose members may interbreed in nature and produce viable fertile offspring together but not with other groups. A scientific name of a species is read as “Genus species”.
What is speciation?
An evolutionary process where a species splits into two or more diverging branches
What is stabilizing selection?
Natural selection where those with intermediate phenotypes survive or reproduce more successfully than extreme phenotypes
What are survivorship curves?
A plot of the number of individuals alive at each age
What is sympatric speciation?
A form of speciation when barriers cause new species to form from a population in the same geographic area
What are sytematics?
The discipline of the classification of organisms and determining their evolutionary relationships
What is taxonomy?
The discipline of naming and classifying forms of life. They are ordered by domain, kingdom, phylum, class, order, family, genus, species
What are vestigial organs?
A feature in an organism that is a historical remnant of a structure from ancestral organisms
Name all the conditions for Hardy-Weinberg equillibrium.
Random mating, no genetic drift, no mutations, no natural selection, no gene flow
Give an example of a vestigial organ.
Ex: Human appendix, Whale hips
What are some methods used to map out systematics between organisms?
Cladograms, Genetics, Homologous structures
What is migration / gene flow?
The movement of alleles into or out of a population. It can occur as a result of the migration of fertile individuals or gametes between populations. Gene flow tends to increase diversity.
