Origin and Diversification of Species Flashcards Preview

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Flashcards in Origin and Diversification of Species Deck (76)
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1
Q

What is the biological definition of a species?

A

one or more populations whose members can potentially interbreed and produce fertile offspring - reproductive isolation between species

2
Q

Which species definition is the least useful for classifying prokaryotes and why?

A

biological (cause they don’t interbreed)

3
Q

How are species classified morphologically?

A

differ in appearance (shape, structures)

4
Q

How are species classified ecologically?

A

have different ecological niches

5
Q

When might morphological classification of species be useful and why?

A

classifying species - can’t observe their behaviour

6
Q

When might ecological classification of species be useful?

A

studies at the ecosystem or large community scale

7
Q

How are species classified phylogenticly?

A

genetic similarities

8
Q

What species concept is useful for classifying organisms that reproduce by cloning?

A

phylogenetic

9
Q

What are some reproductive barriers?

A

habitat isolation, temporal isolation, behavioural isolation, mechanical isolation, gametic isolation, reduced viability,, reduced fertility, hybrid breakdown

10
Q

If there are no reproductive barriers between two species, what happens?

A

they produce viable, fertile offspring - hybrids just as fit as the original species

11
Q

What reproductive barriers prevent a mating attempt?

A

habitat isolation, temporal isolation, behavioural isolation

12
Q

What reproductive bariers allow a mating attempt but prevent fertilization?

A

mechanical isolation and gametic isolation

13
Q

What reproductive barriers allow fertilization but prevent the production of viable, fertile offspring?

A

reduced viability, reduced fertility, and hybrid berakdown

14
Q

What is habitat isolation and how does it prevent reproduction?

A

two species occupy different areas - even though they’re not isolated by obvious physical barriers, they may rarely encounter each other

15
Q

What keeps species distinct?

A

reproductive barriers

16
Q

What is temporal isolation and how does it prevent reproduction?

A

live in same habitat, but breed during different times (of day, season, or year) - can’t mix their gametes

17
Q

If two species live in the same habitat, what is the next reproductive barrier to stop them from reproducing?

A

temporal isolation

18
Q

What is behavioural isolation and how does it prevent reproduction?

A

species-specific courtship behaviours attracting mates may be different between two species - meant to identify potential mates of same species

19
Q

What is mechanical isolation and how does it prevent reproduction?

A

mating can be attempted, but morphological differences prevent its successful completion (i.e. sex organs don’t fit together)

20
Q

What is gametic isolation and how does it prevent reproduction?

A

sperm of one species may not be able to fertilize eggs of another (due to no survival or other biochemical mechanisms preventing penetration of egg membrane) - no fertilization, no baby

21
Q

What are the prezygotic barriers?

A

habitat, temporal, behavioural, mechanical, and gametic isolation

22
Q

What do prezygotic barriers do?

A

impede mating or hinder fertilizaiton if mating does occur

23
Q

What are the postzygotic barriers?

A

reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

24
Q

What do postzygotic barriers do?

A

prevent a hybrid zygote from developing into a viable, fertile cell

25
Q

What is reduced hybrid viability and how does it prevent successful reproduction?

A

genes of different parent species may interact in ways that impair hybrid’s development/its survival in its environment

26
Q

What is reduced hybrid fertility and how does it prevent successful reproduction?

A

hybrids are sterile (number/structure of parent species’ chromosomes differ, so meiosis fails), thus preventing the production of offspring, so genes can’t flow freely between species

27
Q

What is hybrid breakdown and how does it prevent successful reproduction?

A

first-generation hybrids are viable and fertile, but when they mate with one of the parent species, offspring of next gen are feeble or sterile

28
Q

What are two common causes of successful hybrids?

A

captivity and climate change causing ranges to come together

29
Q

What are some examples of successful(ish) hybrids?

A

eastern coyote (coyote x wolf), “ligar” (lion x tiger), “grolar” (polar x grizzly bear), “zeedonk” (zebra x donkey)

30
Q

What is speciation?

A

evolutionary process by which new species arise - splitting of a lineage

31
Q

What are two types of speciation?

A

allopatric speciation and sympatric speciation

32
Q

How do allopatric and sympatric speciation differ?

A

allopatric speciation involves geographic isolation between new speceis and parent; sympatric involves formation of new species without geographic separation

33
Q

What is allopatric speciation?

A

a population forms a new species while geographically isoalted from its parent population

34
Q

What is sympatric speciation?

A

a subset of a population forms a new new species without geographic separation

35
Q

How might two parts of a population be geographically isolated?

A

canyon, mountain range, lake, river, ocean, highway, glacier, elevation…

36
Q

What does geographic isolation between two parts of a population cause?

A

lack of gene flow, and thus allopatric speciation

37
Q

What are incipient species?

A

species in the process of becoming genetically isolated (differentiation within a species) - haven’t fully developed reproductive isolation

38
Q

What can happen when two divergent species come into secondary contact?

A

reinforcement, fusion, or stability

39
Q

What does “allopatric” mean (direct translation)?

A

different country

40
Q

What does “sympatric” mean (direct translation)?

A

same country

41
Q

What is reinforcement?

A

strengthening of reproductive barriers - hybridization is not favoured (species kept distinct after initial divergence)

42
Q

What is fusion?

A

weakening of reproductive barriers (species fuse after initial divergence)

43
Q

What is stability?

A

continued production of hybrid individuals (in hybrid zone between species)

44
Q

What happens in a hybrid zone?

A

region where adjacent species meet and hybridize; reproductive barriers are incomplete so produce some hybrid offspring

45
Q

How can we know if two or more populations are different species?

A

molecular biology (using different assays)

46
Q

What is adaptive radiation?

A

a period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their commmunities

47
Q

What can result in adaptive radiaiton?

A

successive allopatric speciation events over time

48
Q

What is an axample of adaptive radiaiton?

A

Galapagos islands

49
Q

What is colonization of a new island a cause of, and what can multiple colonizations (in an island archipelago) cause?

A

allopatric speciation; can cause adaptive radiation

50
Q

Where does sympatric speciation occur?

A

in the same area (without geographic isolation)

51
Q

What might cause isolation within a population that leads to sympatric speciation?

A

local adaptation to toxicity (e.g. plants growing on mine tailings that are toxic);
meiotic error (chromosomes don’t separate - polyploidy);
hybridization if followed by meiotic errors

52
Q

In which type of organisms is sympatric speciation more likely to occur and why?

A

plants; because meiotic errors and hybridization are more common in plants

53
Q

What does a hybridization event followed by an allopolyploid event immediately lead to?

A

genetic isolation (DIAGRAM - SL 16)

54
Q

How might wheat undergo sympatric speciation?

A

1) two species hybridize (AA x BB), forming sterile hybrid (AB)
2) chromosome set is doubled due to meiotic error (producing AA BB)
4) new species is isolated from parent species
(can occur again to form a new species - AA BB DD, etc.)

55
Q

What two genetic events does sympatric speciation in plants often involve?

A

hybridization and meiotic error leading to polyploidy

56
Q

How does sympatric speciation end in plants?

A

ends when an increase in the number of sets of chromosomes allows for homologous pairing and produciton of gametes that can unite with those of other individuals (immediate reproductive isolation)

57
Q

What other external factor can drive sympatric speciation?

A

sexual selection

58
Q

What is the average rate of speciation events?

A

one about every 6.5 milllion years (ranges from 4000 to 40 million)

59
Q

What might result from the change of a single allele, many alleles, or mulitple gene interactions?

A

speciation

60
Q

What is macroevolution?

A

the cumulative effect of many speciation and extinction events

61
Q

What can be used to study broad patterns in speciation?

A

fossil record, morphological data, molecular data

62
Q

What are punctuated equilibria?

A

periods of apparent stasis punctuated by sudden change

63
Q

How does punctuated equilibria differ from what Darwin envisioned?

A

he imagined a gradual pattern of change over time; whereas punctuated equilibria invovles the sudden appearance of a new species, then stasis

64
Q

What are orthologous genes?

A

same gene in different species (product of speciation)

65
Q

What are paralogous genes?

A

two genes that diverge after a duplication event (forms within a species)

66
Q

EVOLUTION AND DEVELOPMENT SLIDE

A

SL 25

67
Q

What does expression of the HOX gene relate to?

A

limb development in vertebrates (?)

68
Q

What does having different copies of the HOX gene allow?

A

evolution of different functions/features

69
Q

EXPLAIN THE BIOLOGICAL SPECIES CONCEPT AND ITS LIMITATIONS

A

(answer later… one limitation is it doesn’t explain hybrids)

70
Q

EXPLAIN HOW SPECIES BECOME, AND ARE KEPT, DISTINCT

A

(answer later)

71
Q

IDENTIFY AND ARRANGE IN ORDER VARIOUS REPRODUCTIVE ISOLATING MECHANISMS FROM PRE-MATING TO POST-FERTILIZATION

A

(answer later)

72
Q

DISTINGUIH BETWEEN ALLOPATRIC AND SYMPATRIC SPECIATION, DESCRIBE HOW EACH TYPICALLY OCCURS, AND INDICATE WHICH IS MORE COMMON IN PLANTS VS. ANIMALS

A

(answer later)

73
Q

DESCRIBE A PLAUSIBLE SCENARIO OF ADAPTIVE RADIATION THROUGH ALLOPATRIC SPECIATION ON ISLANDS, MOUNTAIN TOPS, OR OTHER ISOLATED AREAS

A

(answer later)

74
Q

COMPARE GRADUALISM AND PUNCTUATED EQUILIBRIUM

A

(answer later)

75
Q

HOW IS GENE DUPLICATION IMPORTANT IN EVOLUTION?

A

(answer later)

76
Q

GIVE EXAMPLES OF HOW DEVELOPMENT PLAYS A ROLE IN EVOLUTIONARY CHANGE, INCLUDING HOX GENES

A

(answer later)