Midterm:Evolution

Question 1

Plato

Answer 1

Typological Thinking
Species are of perfect essence created by god
Unchanging
Variations within species are insignificant

Question 2

Aristotle

Answer 2

Ordered unchanging species into sequence
Least to most complex
Species are fixed types

Question 3

Lamarck

Answer 3

Evolution (species change through time)
Simple organisms originate the base of the chain by spontaneous generation
Move up chain as they evolve
Neither typological or population thinking
Produces better species
Individual’s phenotypes change in response to environment, passed to offspring

Question 4

Darwin and Wallace

Answer 4

Individuals vary, some contribute more offspring to next generation
Population thinking (variation is essential and important)
Descent with modification

Question 5

Transitional features

Answer 5

Intermediate between older and younger species

Strong evidence for change through time

Question 6

Vestigial traits

Answer 6

Functionless
Reduced or incompletely developed
Found in related species

Question 7

Homology

Answer 7

Resemblance due to a common ancestor

Similar traits inherited from a common ancestor

Question 8

Genetic homology

Answer 8

Similar in DNA

Question 9

Developmental homology

Answer 9

Similar in embryo form

Question 10

Structural homology

Answer 10

Similar in adult morphology

Question 11

Darwin’s four postulates

Answer 11

Individuals vary in their traits
Some variations are heritable
Some individuals survive and reproduce better
Certain heritable traits help to survive abs reproduce

Question 12

Directional selection

Answer 12

Causes average phenotype to change in one direction

Reduce genetic variation

Question 13

Stabilizing selection

Answer 13

Favours intermediate phenotype
Reduces variation
Same average

Question 14

Disruptive selection

Answer 14

Favours both extremes
Increases variation
Doesn’t change average

Question 15

Balancing selection

Answer 15

No single phenotype is favoured at all times

Maintains variation

Question 16

Four evolutionary processes

Answer 16

Natural selection
Genetic drift
Gene flow
Mutation

Question 17

Four types of selection

Answer 17

Directional
Stabilizing
Disruptive
Balancing

Question 18

Natural selection

Answer 18

Can maintain, reduce or increase genetic variation

Increases fitness

Question 19

Genetic drift

Answer 19

Reduce genetic variation

Usually reduces fitness

Question 20

Gene flow

Answer 20

Increase or decrease variation

Could increase, decrease or have no effect on fitness

Question 21

Mutation

Answer 21

Increases variation

Usually lower fitness

Question 22

Mechanisms of reproductive isolation

Answer 22

Temporal
Habitat 
Behavioural 
Gametic barrier
Mechanical 

Hybrid viability
Hybrid sterility

Question 23

Dispersal

Answer 23

Population moves to a new habitat, colonizes it, and founds a new population

Question 24

Vicariance

Answer 24

Physical splitting of habitat

Question 25

Allopatric speciation

Answer 25

Speciation that stems from physical isolation

Question 26

Sympatric speciation

Answer 26

Speciation that occurs in same geographic area

Question 27

Autopolyploid

Answer 27

All chromosomes from same species

Question 28

Allopolyploid

Answer 28

Individuals created when parents of two different species mate

Question 29

Possible outcomes of secondary population contact

Answer 29

Fusion of populations (freely interbreed) Reinforcement of divergence (hybrid offspring have low fitness, natural selection favours traits that prevent interbreeding between populations) Hybrid zone formation (area where hybridization occurs) Extinction of one population (poorer competitor for resources becomes extinct) Creation of new species (if hybrid offspring can be successful they may form new species)

Question 30

Intact fossils

Answer 30

Don’t decompose, organic remains preserved

Question 31

Compression fossils

Answer 31

Sediment accumulates on top of material, compressed into thin film

Question 32

Cast fossils

Answer 32

Remains decompose, minerals fill hole and make cast

Question 33

Permineralized fossils

Answer 33

Decompose extremely slowly, dissolved minerals infiltrate cells and harden into stone

Question 34

Precambrian

Answer 34

Earth formation to 4.6 Ba Hadean, archaean, Proterozoic eons Most life unicellular Little oxygen

Question 35

Phanerozoic Eon

Answer 35

Paleozoic, Mesozoic, Cenozoic eras | 541 Ma to present

Question 36

Paleozoic era

Answer 36

Land animals, land plants, and fungi diversified | Ended with Permian extinction

Question 37

Mesozoic era

Answer 37

Began with Permian extinction Ended with Cretaceous extinction Gymnosperms and dinosaurs

Question 38

Cenozoic era

Answer 38

Angiosperm and mammals | Currently in Holocene epoch

Question 39

Cambrian explosion

Answer 39

``` Animals diversified into almost all extant groups Causes: Higher oxygen levels Evolution of predation New niches beget new niches New genes, new bodies ```

Question 40

End Permian extinction

Answer 40

``` Largest mass extinction 90% of species extinct Cause Flood basalts (molten rock) Increased SO2, acid rain Ocean lacked oxygen Sea levels dropped ```

Question 41

End Cretaceous extinction

Answer 41

``` Evidence High levels of iridium (common in asteroids) Huge crater off of Mexico Rocks at impact site had SO4 Dust,soot,ash blocked sun ```