Ecology Test #1

Front 1

evolution

Back 1

species change over time

Front 2

Lamarkian evolution

Back 2

species change over time, based on the great changed of being--less complex organisms start at the base of the chain and evolve up the chain over time

Front 3

population

Back 3

consists of individuals of the same species that are living in the same area at the same time

Front 4

Darwin and Wallace

Back 4

evolution occurs because traits vary among individuals in a population and because individuals with certain traits leave more offspring than others do

Front 5

two predictions of natural selection

Back 5

-Species change through time; -species are related by common ancestry

Front 6

fossil

Back 6

any trace of an organism that lived in the past

Front 7

extant species

Back 7

Species living today

Front 8

vestigial trait

Back 8

a reduced or incompletely developed structure that has no function, or reduced function, but is clearly similar to functioning organs or structures in closely related species

Front 9

homology

Back 9

a similarity that exists in species because they inherited the trait from a common ancestor

Front 10

Genetic homology

Back 10

occurs in DNA, RNA, and amino acid sequences

Front 11

Developmental homology

Back 11

recognized in embryos--many embryos look similar when developing--some mammals have gill pouches

Front 12

Structural homology

Back 12

Similarity in adult morphology/form

Front 13

Three levels of homology

Back 13

genetic, structural, developmental

Front 14

artificial selection

Back 14

When a human chooses certain individuals with desirable traits to reproduce

Front 15

Darwin's four postulates of natural selection

Back 15

1)individual organisms in a pop. vary in traits

2) some of the trait differences are heritable

3)Only some individuals in the pop. survive long enough to produce offspring, some will produce more than others

4)Individuals with certain heritable traits are more likely to survive and reproduce

Front 16

Natural selection

Back 16

Occurs when individuals with certain characteristics produce more offspring than do individuals without those characteristics

Front 17

fitness

Back 17

the ability of an individual to produce surviving ,fertile offspring relative to that ability in other individuals in a pop

Front 18

adapation

Back 18

a heritable trait that increases the fitness of an individual in a particular environment relative to individuals lacking that trait

Front 19

Hardy-Weinberg Principle

Back 19

mathematical null hypothesis for the study of evolutionary process.

Front 20

Claims of hardy weinberg

Back 20

Allele frequencies: p +q = 1

Genotype frequences: p2 + 2pq + q2 =1

When alleles are transmittedvia meiosis and random combinations of gametes, frequencies do not change over time

Front 21

Assumptions of hardy weinberg

Back 21

-Random mating, -no natural selection (all members of of parental generation survived and contributed equally to gene pool) -no genetic drift (selection of population represents actual population) -no gene flow (no immigration or emigration) -no mutation

Front 22

Directional selection

Back 22

The average phenotype of a pop changes in one direction

Front 23

Purifying selection

Back 23

When disadvantageous alleles decline in frequency

Front 24

Stabilizing selection

Back 24

Selection that reduces the extremes in a population. Reduces genetic variation and no change in the average value of a trait over time

Front 25

Disruptive selection

Back 25

Eliminates average phenotype and favors extreme phenotypes

Front 26

Sexual dimorphism

Back 26

Any trait that varies between males and females

Front 27

Genetic drift

Back 27

Any change in allele frequencies in a population due to chance, happens especially in small populations