Terms For Lecture 22 Human Biology

Front 1

A trait that is favored by natural selection and increases an individual’s fitness in a particular environment.

Back 1

adaptation

Front 2

Tendency for individuals to mate with someone who is like themselves, with the effect of reducing the range of trait variance if the similarities relate to heritable traits.

Back 2

assortative mating (positive assortative mating)

Front 3

The study of the geographic distribution of organisms.

Back 3

biogeography

Front 4

A change in the characteristics of a population of organisms over generations as a result of shifts in the relative abundance of various alleles due to mutation, natural selection, genetic drift, and gene flow.

Back 4

biological evolution

Front 5

Definition of a species as a group of individuals that can interbreed and produce fertile offspring but typically cannot breed with members of another species.

Back 5

biological species concept

Front 6

A method for organizing biological diversity.

Back 6

classification systems

Front 7

The phenomenon in which the traits found in two separated populations (which were previously in contact with one another) begin to differ over time. Occurs after gene flow is eliminated between two populations.

Back 7

divergence

Front 8

Relative survival and reproduction of one variant compared to others in the same population.

Back 8

fitness (reproductive fitness)

Front 9

The remains of or an impression of plants or animals that existed in a past geological age and that has been excavated from the soil or rock.

Back 9

fossil

Front 10

Type of sampling error that occurs when a small subset of individuals emigrates from the main population to found a new population. Results in differences in the gene pools of source population and the new population.

Back 10

founder effect

Front 11

A physical movement of genes out of or into a population as individuals leave (emigrate) or enter (immigrate). The result is a change in the frequency of alleles in the gene pool (allele pool).

Back 11

gene flow

Front 12

More accurately called the allele pool; the sum total of all genotypes in a population.

Back 12

gene pool

Front 13

Change in allele frequency that occurs as a result of chance alone.

Back 13

genetic drift

Front 14

Humans and earlier humanlike, bipedal species. Any member of the subtribe Hominina, which includes humans (genus Homo) and their close relatives, but not chimpanzees (genus Pan) or more distantly related primates.

Back 14

hominins

Front 15

Similarity in characteristics as a result of common ancestry.

Back 15

homology

Front 16

A process by which heritable traits conferring survival and reproductive advantage to individuals, or related individuals, tend to be passed on to succeeding generations and become more frequent in a population, whereas other less favorable traits tend to become eliminated.

Back 16

natural selection

Front 17

All individuals of a given species within a given area. A subgroup that is somewhat independent from other groups.

Back 17

population

Front 18

A dramatic but short-lived reduction in population size followed by an increase in population.

Back 18

population bottleneck

Front 19

Technique that relies on radioactive decay to estimate a fossil’s age.

Back 19

radiometric dating

Front 20

Prevention of gene flow between different biological species due to failure to produce fertile offspring; can include pre- and post-mating barriers.

Back 20

reproductive isolation

Front 21

Form of natural selection that occurs when a trait influences the likelihood of mating.

Back 21

sexual selection

Front 22

The evolutionary process by which species originate. One example is isolation followed by genetic drift sufficient to prevent interbreeding between the isolated populations.

Back 22

speciation

Front 23

A group of individuals that can breed together to produce fertile offspring and are generally distinct from other groups in appearance or behavior. In Linnaeus’s classification system, a group in which members have the greatest resemblance.

Back 23

species

Front 24

Theory that all organisms present on Earth today derive from a single common ancestor.

Back 24

theory of common descent

Front 25

Theory that all species present on Earth today are descendants of a single common ancestor and are the products of millions of years of evolutionary change.

Back 25

theory of evolution

Front 26

Theory that individuals with certain traits have greater survival and reproduction than individuals who lack these traits, resulting in an increase in the frequency of successful alleles and a decrease in the frequency of unsuccessful ones.

Back 26

theory of natural selection

Front 27

Features modified to have no, or relatively minor, function compared to the function in other descendants of the same ancestor. Examples in humans include the vermiform appendix and wisdom teeth (3rd molars).

Back 27

vestigial traits