Evolution
The process in which organisms change over time.
Natural Selection
The process that produces adaptation. Natural selection is based on three postulates: 1. the availability of resources is limited; 2. Organisms vary in the availability to survive and reproduce; and 3. Traits that influence survival and reproduction are t
Variation
Differences / variation among species of organisms.
Allele
one of two or more alternative forms of a gene.
Inheritance
The action of inheriting. For example, inheriting eye color.
Mutation
A spontaneous change in the chemical structure of DNA. Variations are the result of mutation. The bigger a population the greater the variation and the slower the fixation of the common or medium alleles.
Genetic Drift
A random change in gene frequencies due to sampling variation that occurs in any finite population. Genetic drift is more rapid in small populations than in large populations. Differences in genetic frequencies.
Gene Flow
The movement of genes from one population to another, or from one part of a population to another, as the result of interbreeding.
Random Mating
A factor assumed by Hardy-Weinberg principle and is distinct from lack of natural selection: in viability selection for instance, selection occurs before mating.
Hardy-Weinberg
The unchanging frequency of genotypes that results from sexual reproduction and occurs in the absence of other evolutionary forces such as natural selection, mutation, or genetic drift.
Gene Frequencies
The fraction of the genes at a genetic locus that are a particular allele (therefore also called allele frequency). For example, a population that contains 250 AA individuals, 200 AS individuals, and 50 SS individuals has 700 copies of the A allele and 30
Founder Effect
A form of genetic drift that occurs when a small population colonizes a new habitat and when a small population colonizes a new habitat and subsequently greatly increases in number. Random genetic changes due to the small size of the initial population ar
Continuous Traits
Cannot be analyzed in the same manner as discontinuous traits. Because continuous traits are often measured and given a quantitative value, they are often referred to as quantitative traits.
Phenotypes
The observable characteristics of organisms. Individuals with the same phenotype may have different genotypes.
Genotypes
The combination of alleles that characterizes an individual at some set of genetic loci.
Neutral Evolutionary Process
Genetic drift, mutation, and gene flow.
Convergent Evolution (Convergence)
The evolution of similar adaptations in unrelated species. The evolution of camera-type eyes in both vertebrates and mollusks is an example of convergence.
Homoplasy
possession of a similar trait that is NOT derived from a common ancestor.
Homology
possession of a similar trait that is derived from a common ancestor.
Common Ancestor
Species are established from a single ancestral population.
Population Genetics
Provides a quantitative underpinning for evolutionary theory. Population genetics is concerned with processes that influence allele or genotype frequencies in populations.
Quantitative Genetics
Deals with traits that vary.
Modern Synthesis
An explanation for the evolution of continuously varying traits that combines the theory and empirical evidence of both Mendelian genetics and Darwinism and quantitative genetics.
Naturalistic Fallacy
A term introduced by G.E. Moore. Argues that it would be fallacious to explain that which is good reductively in terms of natural properties such as "pleasant" or "desirable".
Taxonomy
A branch of biology that is concerned with the use of phylogenies for naming and classifying organisms.
Unifomitarian
Lyell's principle that holds that slow, ongoing processes can produce dramatic geological change.
Darwin's 3 Postulates
1. There is variation among individuals, and this variation affects an individual's ability to survive.
2. More individuals are born than can survive.
3. Variation is passed from parents to offspring, or inherited.
Stabilizing Selection
Selection in which individuals in the middle of a phenotypic spectrum are most fit. Favors the middle of the spectrum, meaning those individuals with an average measurement of the phenotype. Those at the highest point will have the highest fitness, those
Disruptive Selection
Organisms that are at the lower end of the phenotypic spectrum experience higher fitness than those near the middle of the spectrum. Organism at the upper end of the phenotypic spectrum experience higher fitness than those near the middle of the spectrum.
Directional Selection
Directional selection on a characteristic will occur when small individuals have the highest fitness. Directional selection on a characteristic will occur when large individuals have the highest fitness.
Adaptation
A feature of an organism created by the process of natural selection.
Maladaption
Detrimental to fitness.
Fitness
Is the central idea in evolutionary and sexual selection theories. It can be defined either with respect to a genotype or to a phenotype in a given environment.
Sexual Selection
In sexual selection most of the costs of reproduction are borne by females. Since females gain reproductive success more by obtaining resources and avoiding predators than by seeking many mating opportunities, they can be considered the "ecological sex".
Reproductive Success
Defined as the passing of genes onto the next generation in a way that they too can pass on those genes.
Limits on Reproductive Success to Different Sexes
Bateman's principle states that male reproductive success is more limited by access to females than female reproductive success is limited by access to males.
Altruism
behavior that is costly to the individual performing the act, but beneficial to some other individuals.
Hamilton's Rule
says that natural selection favors altruistic behaviors when the total benefit to the group members with the altruism alleles is higher than the cost to the individual, kin members form groups that share alleles, groups of altruists have higher average fi
Inclusive Fitnee
The ability of an individual organism to pass on its genes to the next generation, taking into account the shared genes passed on by the organism's close relatives. Part of the group selection idea. Being able to copy more of one's genes with other people
Natural selection works on level of individuals or group?
Natural selection favors traits that increase individual fitness.
Correlation
a connection between two variables. The idea that there are two genetic loci that if they're on the same chromosome than they will cross over.
Local Optimum
The idea that natural selection is blind. The best solution to a problem within a small neighborhood of possible solutions.
Human Genetic Variation
People in different geographic areas have similar genetic variations. Humans have less variation than all other great ape species because at some point recently the human population was small and we've had less time to bring variation back up.
Within Group & Between Group Variation
There is more variation within region groups than there is between group variation.
Genetic Distance
Genetic distances between human groups increase with geographic distances between them.
SNPs
Variation at a single base pair is called a SNP, or single nucleotide polymorphism.
Human genetic variation patterns in different continents / population
Genetic distances between human groups increase with geographic distances between them.
In humans, between-region variation accounts for only about 10% of total genetic variation.
Humans are less genetically variable then most great ape species.
Most gene
Social Enhancement
Social enhancement occurs when other individuals modify the environment and as a consequence makes it easier for you to acquire the same behavior as others in a cultureCumulative culture is not the product of social enhancement.
Observation Learning
in observational learning you watch other individuals and acquire behavior directly through observation. Both of these mechanisms (social enhancement & observational learning) can create cultural traditions.
Cumulative Cultural Traditions
Cumulative culture arises from the accumulated innovations of many generations of learners. Cumulative culture is not the product of social enhancement. Observational learning allows cultural traditions to be cumulative.
Human Races in Biological / Cultural Context
Knowing the phenotypes of individuals does NOT tell you a lot about their genes.
Racial classification systems differ widely in the number of races into which humans are categorized.
In some racial classification systems, siblings could be placed into dif
Two Common Assumptions in Regards to Race
1. Many assume that human variation can be neatly categorized into a small number of discrete categories.
2. Knowing an individual person's race gives you important biological information about them.
Are assumptions regarding race true or false and why?
Both assumptions are false. Human races are not useful for understanding human variation.
Because most variation is found within groups, not among them, this means that there is not much differentiation among groups, which is what you would expect if race
Evidences on the (non)existence of human races:
These four lines of evidence all suggest that racial categories are not natural biological entities. As we have seen, species are often natural biological entities: the boundaries between them are discrete and there are few intermediate cases. In contrast
Human Genetic Variation (explanation)
Variation among groups can be due to environmental factors rather than genetic. Where we find geographic patterns in human phenotypic or genetic variation, those patterns tend to involve gradual (clinal) change across geographic space, rather than the sha
Human Phenotypic Variation
Phenotypic variation between groups is due to both genetic and environmental factors. For example, an individual's height is the product of her genes as well as her diet during growth and development. Perceptions of phenotypic variation are tightly linked
Phylogeny
Phylogeny (evolutionary history): Understanding a phenotypic trait by considering evolutionary patterns of change over time in closely and distantly related species. For example, assessing human mating systems by comparing them to mating relationships in
Mating System
In large comparative studies of mating systems across human cultures, the overwhelmingly most common mating system is polygyny. Polygyny is the mating system where one man is married to multiple wives. The second most common type of mating system exhibite
What does OSR stand for?
Operational Sex Ratio
OSR
If the ratio of males to females were to increase in the human species, the operational sex ratio (OSR) would predict an increase in male to female body size dimorphism because of increased male competition for mating opportunities.
If the female interbir
EEA
The EEA concept can explain why some behaviors that are maladaptive today may have been selected for in the past.
EEA stands for Environment(s) of Evolutionary Adaptedness.
Environments of Evolutionary Adaptedness (EEA) and it can be simply defined as the