Chapter 18: evolution and origin of species

Question 1

artificial selection

Answer 1

when human chose phenotypes we want and breed to create more ideal hybrids and breed (also known as selective breeding)

Question 2

what were darwin’s postulates

Answer 2

• characteristics are heritable (passed to an offspring)
• the more offspring that are present that can survive creates a competition
• characteristics of offspring vary and variations are heritable

Question 3

natural selection

Answer 3

idea that organisms that are more adapted to an environment are more likely to survive

Question 4

how does homologous structures support evolution

Answer 4

the similar construction of these appendages that indicates that organisms share a common ancestors

Question 5

what are the key ideas of evidence of evolution

Answer 5

• divergent and convergent evolution
• fossil record
• homologous structures
• vestigial structures
• biogeography
• molecular biology

Question 6

convergence

Answer 6

similarities occur not because of common ancestry but because of similar selection pressures

Question 7

how does biogeography support evolution

Answer 7

development and presence of species based on a location
- groups that develop in certain regions or continents
- when species develop because of isolation by physical land barriers

Question 8

how does molecular biology support evolution

Answer 8

• DNA analysis shows that closely related organisms have similar DNA
• evolution of new functions for proteins after mutations occur

Question 9

What are the misconceptions of evolution

Answer 9

• evolution is just a theory
• individuals evolve: its populations that evolve not the individual
• evolution explains the origin of life
• organisms evolved on purpose

Question 10

what is a species

Answer 10

a group of organisms that can interbreed and produce viable and fertile offspring

Question 11

what is a hybrid

Answer 11

a cross between two species

Question 12

what is a gene pool

Answer 12

a collection of all the variants of genes in a species

Question 13

what is speciation

Answer 13

the movement of species (the movement of genetic information of a species)

Question 14

what is allopatric speciation

Answer 14

speciation that involves geographic isolation (this can include anything that changes the environment at all)

Question 15

what is the ultimate example of allopatric speciation

Answer 15

panagea

Question 16

what are the three types of allopatric speciation

Answer 16

• dispersal
• vicarience
• adaptive radiation

Question 17

what is dispersal speciation

Answer 17

happens is when a few members of a species move to a new geographical areas

Question 18

what is vicariance speciation

Answer 18

happens when a natural situation arises to physically divide organisms (happens in cases of storms and natural disasters)

Question 19

what is adaptive radiation in terms of speciation

Answer 19

when a single species exists and through events is dispersed out
- every animal comes from the same species (founder species)

Question 20

what is sympatric speciation

Answer 20

speciation that happens within the same physical location and conditions

Question 21

what are the two types of sympatic speciation

Answer 21

• chromsomal errors in cell division
• reproductive isolation

Question 22

what are the types of chromosomal errors that can happen in sympatric speciation

Answer 22

• aneuploidy
• autopolyploidy
• allopolyploidy

Question 23

what are the types of reproductive isolation that can take place in sympatric speciation

Answer 23

• prezygotic barriers
• postzygotic barriers

Question 24

what is speciation

Answer 24

occurs when a group within a species separates from other members of its species and develops its own unique characteristics

Question 25

when does speciation occur

Answer 25

- when groups become isolated geographically for a long period of time - mutations/changes in each group over time lead to the groups no longer being reproductively compatible

Question 26

what is aneuploidy speciation

Answer 26

happens when there are two few or many chromosomes in an organism (can happen during anaophase and metaphase when chromosomes are not evenly split)

Question 27

what is autopolyploidy speciation

Answer 27

happens when two or more set of chromosomes after divison ( results from an error in meiosis 1 when the whole PMAT stages are not followed by cytokinesis)

Question 28

what is allopolyploid speciation

Answer 28

when gametes from two different species combine (typically results in an offspring that is sterile)

Question 29

what is prezygotic isolation in sympatric speciation

Answer 29

something that physically prevents gametes from meeting

Question 30

what are the types of presygotic barriers

Answer 30

- temporal isolation - habitat isolation - behaviourial isolation

Question 31

what is temporal isolation

Answer 31

when species have different breeding schedules (ie. human ovilation cycle)

Question 32

what is habitat isolation

Answer 32

members of species move or are otherwise seperated (anything that migrates)

Question 33

what is behaviourial isolation

Answer 33

certain actions or behaivours that impacts reproduction (what attracts two organisms together)

Question 34

what is postzygotic isolation

Answer 34

a barrier that blocks the reproduction after fertilization and zygote formation

Question 35

what is hybrid inviability

Answer 35

when an embryo is produced but cannot survive its development (chromosomes won't line up)

Question 36

what is hybrid sterility

Answer 36

when different species can produce a viable offspring but that offspring cannot reproduce

Question 37

what is hybrid zones

Answer 37

an area in regards to speciation where two closely related species interact and interbreed

Question 38

what is reinforcement

Answer 38

a process where hybrids are less fit and thus there is nudge towards further divergence between the two species

Question 39

what are the types of hybrid zones

Answer 39

- reinforcement - fusion -stability

Question 40

whats is fusion

Answer 40

when reproductive barriers weaken until the two species become one (when the dispursal event doesn't properly work so the two species come back together)

Question 41

what is stability in regards to hybrid zones

Answer 41

when a species seperates and the fit hybrids continue to be produced

Question 42

what is rate of speciation

Answer 42

a graphically measurement of how a species changes over time to and new species are formed

Question 43

gradual speciation

Answer 43

when species diverge gradually through time with small step (species diverge at a slow and steady pace as trait change in small increments)

Question 44

what is punctuated equilibrium in regards to rates of speciation

Answer 44

when a species exhibits a large change in relatively short period of time followed by long periods of stasis (species diverge quickly and then remain unchanged for a long period of time)