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SBI3U - Evolution > Speciation > Flashcards

Speciation Flashcards

1
Q

What is a biological species?

A

A biological species is a population in nature where where individuals breed to produce fertile offspring.

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2
Q

What is microevolution?

A

Microevolution is the change in allele frequency’s and the phenotypic traits within a population and over a period of time.

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3
Q

What might cause microevolution?

A

Mutations, genetic drift, non random mating, natural selection.

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4
Q

What is speciation?

A

Speciation is the formation of species from already existing species.

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5
Q

What is another name for speciation?

A

Macroevolution

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6
Q

What is a biological species?

A

It includes all members of a populations that can breed under natural conditions.

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7
Q

Populations of different species do not exchange genetic information, why is this?

A

They have different gene pools

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8
Q

Explain, what is a reproductive isolating mechanism?

A

It is any biological factor that prevents two populations from interbreeding when they live in the same population.

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9
Q

What are the two types of reproductive isolating mechanisms?

A

Pre-zygotic and post-zygotic.

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10
Q

Pre-zygotic barriers means…

A

It prevents fertilization and the formation of zygotic.

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11
Q

What are examples of pre-zygotic barriers?

A

Behavioural isolations, temporal isolation, ecological/habitat isolation, mechanical isolation, and gametic isolation.

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12
Q

Describe behavioural isolation, include an example.

A

Different species use different mating clues to find and attract a mate. Example: male frogs have unique calls that attract only females of their own species.

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13
Q

Describe temporal isolation, provide an example.

A

Different species may breed at different times of the year. Example: one species may reproduce in the spring, but the other species may reproduce in the summer.

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14
Q

Describe ecological isolation, provide an example.

A

Very similar species may occupy different habitats within a region. Example: a bird that lives at high elevations, and a bird that lives at a low elevation.

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15
Q

Describe mechanical isolation.

A

Differences in morphological features may make two species incompatible.

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16
Q

Describe gametic isolation.

A

Male gametes might not be able to recognize and fertilize an egg of a different species.

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17
Q

Post-zygotic barriers means…

A

It can prevent an already fertilized egg from growing into viable and reproducing adults.

18
Q

What are the three post-zygotic barriers called?

A

Zygotic mortality, hybrid inviability, and hybrid infertility.

19
Q

Describe zygotic mortality, provide example.

A

Mating and fertilization are possible but genetic differences result in zygote that is unable to develop properly. Example: some sheep and goat are able to mate but zygote is not viable.

20
Q

Describe hybrid inviability, provide example.

A

A hybrid individual develops but either dies before birth, or if born alive cannot survive to maturity. Example: tigers and leopards are able to cross but zygote develops and results in a still born.

21
Q

Describe hybrid infertility, provide example.

A

Hybrid offspring remains healthy and are viable but sterile.

22
Q

What are the two types of speciation in which gene flow is disrupted in a population?

A

Allopatric Speciation and Sympatric Speciation

23
Q

What is allopatric speciation?

A

New species will form when a single species is separated into two geographically isolated populations.

24
Q

How does allopatric speciation work in terms of disrupting gene flow in a population?

A

A physical barrier divides one population into two or more. From there these groups can no longer exchange genetic information. Over generations these separated populations will grow more and more unalike.

25
Q

In allopatric speciation, after time, why do these separate populations look less alike?

A

They look less alike because any mutation that arises in one will not be shared with the other population. Differences in environment will also lead to different forms of natural selection. Genetic drift is also the result.

26
Q

Over time what happens to the species that underwent allopatric speciation?

A

These separate populations will evolve to some sort of reproductive isolating mechanism.

27
Q

What is sympatric speciation?

A

It is a new species that evolves from within a large population.

28
Q

When does sympatric speciation occur?

A

It occurs when individuals in a population become genetically isolated from the larger population.

29
Q

What are some factors that might cause sympatric speciation?

A

Chromosomal changes, non random mating that may alter gene flow.

30
Q

Where is sympatric speciation more common?

A

It is more common in plants.

31
Q

Can a species that is affected by sympatric speciation occur in a single generation?

A

Yes. New species are generated in a single population if genetic change results in a reproductive barrier between the offspring and the parent population.

32
Q

What is polyploidy?

A

Polyploidy is a mutation that causes an error in cell division that results in extra sets of chromosomes.

33
Q

Mutations causing polyploidy ________ the number of chromosomes in an individual.

A

Double

34
Q

What is a haploid?

A

Gamete that produces one set of chromosomes is a haploid.

35
Q

What is a diploid?

A

Gamete that produces two sets of chromosomes is a diploid.

36
Q

If errors occur during meiosis and chromosomes do not separate do the gametes produce a haploid or a diploid?

A

The gametes produce a diploid.

37
Q

Can polyploid species produce fertile offspring with their original species?

A

No. If they mated with their original species it would result in a sterile offspring. Only when a polyploid mates with another polyploid is its offspring fertile.

38
Q

What happens when two diploid gametes fuse?

A

Diploids have two sets of chromosomes, so if two diploids fuse, their offspring will have four sets of chromosomes. (Tetraploid)

39
Q

What if a tetraploid offspring survives and produces normal meiosis. What type of gamete would it produce?

A

It would produce diploid gametes.

40
Q

Polyploids that are fertile produce a ________.

A

Hybrid species.

41
Q

What type of individual does a hybrid turn into?

A

Hybrids become diploid individuals with a mix of chromosomes from two original species.

42
Q

Give examples of how humans participate in isolating populations and prevents gene flow.

A

Agricultural expansion, construction of roads, wilderness areas for recreation and tourism, urban subdivisions, hydroelectric power generation.

SBI3U - Evolution (5 decks)

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