cycle 8 Flashcards

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1
Q

Homo Sapiens

A

homo - genus

sapiens - epithet

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2
Q

what is a species?

what defines a species?

A
  • no universal species concept…
  • populations with different traits, populations that successfully mate with each other (not with other populations), populations that don’t exchange genetic material with other populations
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3
Q

ecological species concept

A

a concept of species in which a species is a set of organisms adapted to a particular set of resources, called a niche, in the environment.

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4
Q

morphological species concept

A

a set of organisms that look similar to each other and is distinct from other sets

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5
Q

biological species concept

A

a group of organisms that can successfully interbreed and produce fertile offspring - reproductively isolated

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6
Q

phylogenetic species concept

A

group of populations with a recent evolutionary history

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7
Q

evolutionary tree

A
  • groups are monophyletic (all descendants from common ancestor)
  • Must decide how much evolutionary change defines a group or species
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8
Q

Comparing species concepts

A

different concepts for delineating species give different answers – it’s not clear cut

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9
Q

Reproductive isolating mechanisms (barriers to gene flow)

A
  • Meet > Mate > Fertilization > Zygote > Development > Offspring Variability
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10
Q

Prezygotic Isolation Mechanisms

A

-Ecological isolation
-Behavioral Isolation
-Temporal Isolation
Mechanical isolation
-Gametic isolation

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11
Q

Postzygotic Isolation Mechanisms

A
  • Hybrid sterility

- Hybrid breakdown

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12
Q

Ecological isolation

A

occupy same region, but live-in different habitats

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13
Q

Behavioral Isolation

A

signals not recognized by another

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14
Q

Temporal Isolation

A

mate a different times of the year

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15
Q

Mechanical isolation

A

differences in structures prevent interbreeding

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16
Q

Gametic isolation

A

gametes not compatible, cannot fertilize

17
Q

Hybrid sterility

A

offspring survive but are sterile

18
Q

Hybrid breakdown

A

First gen hybrids produce viable gametes/offspring, but second gen offspring have lower fitness, are sterile, or are inviable

19
Q

Allopatric Speciation

A

two populations are geographically separated physically - geological barrier that individuals cannot cross.

20
Q

Secondary contact

A

when populations interact again after being geographically separated.

21
Q

Outcome of secondary contact

A

may resume interbreeding, may become partly/fully reproductively isolated

22
Q

reproductive isolation

A

causes interbreeding slowy

23
Q

fusion

A

populations interbreed quickly

24
Q

Hybrid zone

A

individuals of previously separated populations interbreed

25
Q

hybrids are…

A

well adapted to environments outside of hybrid zone, low fitness, at risk of evolution. hybrids are favoured!

26
Q

Reinforcement

A

accelerates isolation after secondary contact. promotes evolution of prezygotic isolation

27
Q

Sympatric speciation

A

populations are not geographically or environmentally separated. not very common

28
Q

Polyploidy in plants

A

changes # of sets of chromosomes. Causes rapid speciation. Eg: diploid parental generation can’t interbreed with their tetraploid offspring. This is because gametes have different # of chromosomes = gametic isolation.

29
Q

Allopolyploidy in plants

A

cannot undergo meiosis, chromosomes are too different to pair properly. DNA replicates, but cell wont divide – chromosome doubling. Produces gametes that are not compatible with species A/B individuals, creating new species

30
Q

speciation

A

more differences evolve and accumulate, causing populations to diverge further apart