Ch 11. Species and Races

Question 1

species

Answer 1

group whose members have the greatest resemblance. each has 2 part name

Question 2

2 part name of species

Answer 2

1st: indicates genus, a broader group
2nd: specific to species within genus

Question 3

biological species

Answer 3

consistent definition to determine differences between species

Question 4

reproductively isolated

Answer 4

can interbreed and produce fertile offspring, but cant reproduce with other species

Question 5

gene pool

Answer 5

sum total of all alleles within a species. makes an impermeable container for gene pool. change in frequency can only happen within a species

Question 6

prefertilization barriers

Answer 6

failure to mate/produce an embryo

Question 7

spatial isolation

Answer 7

prefert. different species dont come in contact

Question 8

behavioral isolation

Answer 8

prefert. ritual mating behaviors differ

Question 9

mechanical isolation

Answer 9

prefert. incompatible sex organs

Question 10

temporal isolation

Answer 10

prefert. timing of readiness to reproduce is diferent

Question 11

gamete incompatibility

Answer 11

prefert. proteins on egg that allow sperm to bind dont work for another species

Question 12

postfertilization barriers

Answer 12

fertilization occurs, but hybrid cant reproduce

Question 13

hybrid inviability

Answer 13

postfert. zygote cant complete development because genetic instructions incomplete

Question 14

hybrid sterility

Answer 14

postfert. hybrid cant produce offspring because chromosome number is odd. (mule)

Question 15

speciation

Answer 15

evolution of species from an ancestral form. isolated population diverge in traits. divergance can lead to reproductive isolationa nd formation of a new species. 3 steps necessary

Question 16

3 necessary steps for speciation

Answer 16

1. isolation of gene polls of subgroups/populations of the species
2. evolutionary changes in gene pools of 1 or both of isolated population
3. evolution of reproductive isolation between population, preventing future gene flow

Question 17

founder hypothesis

Answer 17

diversity of unique species on oceanic islands and isolated bogs, caves, and lakes resulted from colonization by 1 species that rapidly speciated, taking advantage of many different resources. allopatric or sympatric.

Question 18

allopatric

Answer 18

isolation due to geographic barrier

Question 19

sympatric

Answer 19

separation of gene pool even when near each other

Question 20

polyploidy

Answer 20

process of chromosome duplication. if occurs in hybrid, fertility may be possible again. mostly in plant and some insects and frogs.

Question 21

instantaneous speciation

Answer 21

hybrids from polyploidy may produce offspring and are immediately creating a new species (can’t reproduce with parental species) due to genetic incompatability (polyploidy creates double the genes as the parents)

Question 22

gradualism

Answer 22

speciation occurring over millions of years with tiny changes accumulating

Question 23

punctuated equilibrium

Answer 23

dramatic changes in few thousand years, followed by many thousands or millions of years of little changes

Question 24

biological race

Answer 24

populations of a single species that have diverged. little gene flow between them, evolutionary changes differ between populations

Question 25

geneological species concept

Answer 25

species is smallest group of reproductively compatible organisms containing all known descendants of a common ancestor. emphasizes unique evolutionary lineages, increasing number of identifiable species

Question 26

human races

Answer 26

white, black, pacific islander, asian, australian, aborigine, and native american. physical differences used to define are skin color, hair texture, eye, skull, and nose shape

Question 27

morphological species concept

Answer 27

individuals of same species look alike (similar morphology). correlated with isolation of gene pools. mostly used by paleontologists

Question 28

out-of-africa concept

Answer 28

homio sapiens evolved once in africa from homo erectus. most supportive data

Question 29

multiregional hypothesis

Answer 29

homo sapiens evolved throughout range of homo erectus

Question 30

hybridization-and-assimilation hypothesis

Answer 30

homo sapiens evolved out of africa and migrated and hybridized with homo erectus in different areas of globe

Question 31

allel frequency

Answer 31

trait in one population is more common than in the other. result of evolution.

Question 32

2 traits of isolated race

Answer 32

1. unique alleles specific to race | 2. differences in allele frequency for some genes relative to other races

Question 33

hardy-weinberg theorem

Answer 33

allele frequency remains stable in large populations that randomly mate and experience no migration or natural selection. forms basis of modern science of population genetics. describes relationship between allele frequency and genotype frequency for a gene with 2 alleles in a stable population.

Question 34

hardy- weinberg cont.

Answer 34

frequency is written 'p' and 'q'. each gamete carries one copy of each gene (frequency of gametes=frequency of alleles). assume every member has equal chance of mating with any member of opposite sex (like lottery drawing). drawn like punnet square, including frequency. equation: (pxp)+2pq+(qxq)=1

Question 35

HW#1: p=80% dominant(A) q=20% recessive(a). what are the frequencies?

Answer 35

anser: AA=0.64, Aa=0.32. aa=0.04 0.64+0.32+0.04=1 work: pxp+2pq+qxq 0. 8x0.8+2(0.8x0.2)+0.2x0.2

Question 36

human race

Answer 36

NOT biological groups. no race-specific alleles. (sickle cell not a black disease, cystic fibrosis not a white disease). hypothesis that human races represent independant evolutionary groups isn't supported by observations.

Question 37

why is human race not a true race?

Answer 37

morphological characteristics (skin, hair, eye shape, etc) used to classify race are determined by multiple genes, therefore those genes should be specific to certain gene pools. no clear boundaries for gene pool. 'mixing' for thousands of years. races fail to meet criteria for identifying populations as isolated from each other

Question 38

why do human groups differ?

Answer 38

natural selection. ex1: sickle cell anemia is an adaptation that increases fitness in malaria prone areas ex2: nose shape is adaptation to climate. long and narrow for dry climates, short and wide for tropical climates

Question 39

convergent evolution

Answer 39

traits shared by unrelated populations due to similarities in environments. cause of skin color (exposure to UV light)

Question 40

Dark skin and UV light

Answer 40

absorbs less UV light. UV interferes with storing folate which inturn causes birth defects, and low sperm production

Question 41

light skin and UV light

Answer 41

allows for more vit D absorption from sun in darker environments

Question 42

genetic drift

Answer 42

change in allele frequency due to chance. 3 types, founder effect, bottleneck population, and small populations

Question 43

founder effect

Answer 43

genetic drift. small population of larger population leave and establish new population. small populations gene pool is poor reflection of larger gene pool. genetic diseases is more common due to small gene pool with some individuals carrying recessive genes in high frequency

Question 44

sampling error

Answer 44

small population gives poor reflection of larger populations gene pool

Question 45

bottleneck population

Answer 45

genetic drift. dramatic, short lived reduction in population size (i.e. natural disaster). new population differs in gene frequency because survivors have 'sampling error' and gene pool isnt exact match as before

Question 46

small populations

Answer 46

genetic drift. allele frequency more apt to change in chance events. frequency may substantially change after a few generations. can lead to extinction in plants and animals.

Question 47

sexual selection

Answer 47

trait that influences the likelihood of mating

Question 48

assortive mating

Answer 48

choosing a mate based on attractive traits. exaggerates physical differences between populations

Question 49

race in human society

Answer 49

social structure in humans, no biological meaning

Question 50

racism

Answer 50

idea that some groups of people are naturally superior that others