Bio 2 Exam 1

Front 1

Allopatric speciation

Back 1

Geographic separation of populations restricts gene flow

Front 2

Sympatric speciation

Back 2

Occurs in populations that live in the same geographic area. Reproductive barrier must evolve. Gene flow may be reduced

Hint 2

Most important in plants

Front 3

Microevolution

Back 3

Changes in Allen frequencies

Front 4

Macro evolution

Back 4

Broad pattern of evolution over time. Include changes in the evolution of terrestrial vertebrates, the impact of mass extinctions on the diversity of life, and the origin of key adaptations

Front 5

Biological species concept

Back 5

Species is a defined group of populations whose members have the potential to interbreed (viable offspring) (no viable offspring of bred with other such group)

Front 6

Reproductive isolation

Back 6

Existence of biological barriers that prevent viable fertile hybrids

Front 7

Prezygotic barriers

Back 7

Prevent attempt at mating, prevent success of mating, or hindering fertilization

Front 8

Prezygotic barrier examples

Back 8

Habitat isolation, behavioral isolation, temporal isolation, mechanical isolation, and gametic isolation

Front 9

Postzygotic barriers

Back 9

Reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown

Front 10

Morphological species concept

Back 10

Defines species by body shape and other structural features

Front 11

Ecological species concept

Back 11

Defines species in terms of ecological niche

Front 12

Phylogenetic species concept

Back 12

Defines a species as the smallest group of individuals that shares a common ancestor and forms one branch on the tree of life

Front 13

Polyploidy

Back 13

Accidents during cell division that result in extra sets of chromosomes (more common in plants)

Front 14

Autopolyploid

Back 14

An individual that has more than chromosome sets all derived from a single species

Front 15

Allopolyploid

Back 15

When two different species mate and produce an polyploid individual

Front 16

Habitat differentiation

Back 16

May lead to sympathetic speciation

Front 17

Sexual selection

Back 17

May lead to sympathetic speciation

Hint 17

Lake Victoria cichlids

Front 18

Reinforcement

Back 18

When hybrids are less fit that members of the parental species, natural selection strengthens prezygotic barriers

Front 19

Punctuated equilibrium

Back 19

Evolution pattern of apparent stasis punctuated by sudden change; Eldredge and Gould

Front 20

4 main stages of early life

Back 20

1. Abiotic synthesis of small organic molecules

2. Joining of monomers into macromolecules

3. Packing of molecules into protocols, droplets with membranes that maintained a distinct internal chemistry

4. Origin of self-replicating molecules

Front 21

Ribozymes

Back 21

RNA catalysts make complementary copies of short pieces of RNA when supplied with nucleotide blocks

Front 22

Radiometric dating

Back 22

Dating rock strata based on the decay of radioactive isotopes

Front 23

Geologic record

Back 23

History of life on earth (4eons)

Hadean, Archaean, and Proterozoic (4 Bill)

Phanerozoic eon (last 1/2 bill)

Front 24

Phanerozoic eon

Back 24

Paleozoic era, Mesozoic era, and Cenozoic era

Front 25

Stromatolites

Back 25

Rocks composed of layers of Cyanobacteria and sediment

Oldest known fossils 3.5 bill

Front 26

Endosymbiosis theory

Back 26

Suggests mitochondria and plastids were formerly small prokaryotes that began living within larger cells

Front 27

Serial endosymbiosis

Back 27

Theory supposed mitochondria evolved before plastids

Front 28

Cambrian explosion

Back 28

Many phyla of animals appear suddenly in the fossil record

Front 29

Plate tectonics

Back 29

Earths continents shift across the planet’s surface on great plates of crust that float on hot underlying mantle

Front 30

Heterochrony

Back 30

An evolutionary change in the rate or timing of developmental events

Front 31

Paedomorphosis

Back 31

Rate of reproductive development accelerates compared to the development of other organs, a sexually mature stage can retain juvenile structures

Front 32

Homeotic genes

Back 32

Master regulatory genes that determine where wings and legs develop etc

Front 33

Exaptations

Back 33

Structures that had one function originally and layer evolved another or sifferentndunction

Front 34

Thomas Malthus

Back 34

Essay on human suffering

Organisms have the capacity to over reproduce

Front 35

Carolus Linnaeus

Back 35

Founder of binomial classification system

Front 36

On an evolutionary tree

Back 36

Homologous characteristics form a nested pattern

Common ancestor of the lineages beginning there and to the right of it

Front 37

George’s cuvier

Back 37

Developed paleontology

First proposed modern idea of extinction

Front 38

Convergent evolution

Back 38

Similar characteristics but developed from different groups of organisms

Front 39

Uniformitarianism

Back 39

Idea that same geologic forces are operating today that occurred in the past (Hutton and Lyell)

Front 40

Principle of genetics

Back 40

Mendel

Front 41

Lamarck

Back 41

First proposed that acquired characteristics are inherited

use and disuse of parts

Front 42

Aristotle

Back 42

Developed the scala naturae

Front 43

Darwin

Back 43

Theory of evolution by means of natural selection

Hint 43

Descent with modification

Front 44

Endemic

Back 44

Organisms found in only 1 part of the world

Front 45

Adaptations

Back 45

Inherited characteristics of organisms that enhance their survival and reproduction in specific environments

Front 46

Evolution: populations

Back 46

A change in a population’s allele frequencies over generations

Front 47

Neutral advantage

Back 47

Differences in DNA sequence that do not confer a selective advantage or disadvantage

Front 48

Balancing selection

Back 48

Maintains stable frequencies of two or more phenotypic forms in a population

Front 49

Stabilizing selection

Back 49

Reduced variation and maintains the status quoted for a particular phenotypic character

Front 50

Directional selection

Back 50

Selection for a single form

Front 51

Heterozygous advantage

Back 51

One mechanisms of balancing selection

Front 52

Disruptive selection

Back 52

Squirrel example of advantageous small or large but not medium

Front 53

Adaptive radiations

Back 53

Periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles or niches

Front 54

Catastrophism

Back 54

Cuvier: boundaries between strata were due to local floods or droughts that destroyed the species then present

Front 55

Gradualism

Back 55

Hutton: profound geologic changes took place though the cumulative effect of slow but continuous processes identical to those currently operating

Front 56

Gene flow

Back 56

Transfer of alleles between populations

Front 57

Genetic drift

Back 57

Chance events that alter allele frequencies

Front 58

Discrete characters

Back 58

Usually determined by a single locus with different alleles that produce the distinct phenotypes

Front 59

Quantitative characters

Back 59

Vary along a continuum within a population

Front 60

Average heyerozygosity

Back 60

Measures gene variability, the average percent of gene loci that are heyerozygous

Front 61

Nucleotide variability

Back 61

Measures mean level of difference in nucleotide sequences among individuals in a population