cycle 8

Question 1

Homo Sapiens

Answer 1

homo - genus

sapiens - epithet

Question 2

what is a species?

what defines a species?

Answer 2

• 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

Question 3

ecological species concept

Answer 3

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.

Question 4

morphological species concept

Answer 4

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

Question 5

biological species concept

Answer 5

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

Question 6

phylogenetic species concept

Answer 6

group of populations with a recent evolutionary history

Question 7

evolutionary tree

Answer 7

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

Question 8

Comparing species concepts

Answer 8

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

Question 9

Reproductive isolating mechanisms (barriers to gene flow)

Answer 9

• Meet > Mate > Fertilization > Zygote > Development > Offspring Variability

Question 10

Prezygotic Isolation Mechanisms

Answer 10

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

Question 11

Postzygotic Isolation Mechanisms

Answer 11

• Hybrid sterility

- Hybrid breakdown

Question 12

Ecological isolation

Answer 12

occupy same region, but live-in different habitats

Question 13

Behavioral Isolation

Answer 13

signals not recognized by another

Question 14

Temporal Isolation

Answer 14

mate a different times of the year

Question 15

Mechanical isolation

Answer 15

differences in structures prevent interbreeding

Question 16

Gametic isolation

Answer 16

gametes not compatible, cannot fertilize

Question 17

Hybrid sterility

Answer 17

offspring survive but are sterile

Question 18

Hybrid breakdown

Answer 18

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

Question 19

Allopatric Speciation

Answer 19

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

Question 20

Secondary contact

Answer 20

when populations interact again after being geographically separated.

Question 21

Outcome of secondary contact

Answer 21

may resume interbreeding, may become partly/fully reproductively isolated

Question 22

reproductive isolation

Answer 22

causes interbreeding slowy

Question 23

fusion

Answer 23

populations interbreed quickly

Question 24

Hybrid zone

Answer 24

individuals of previously separated populations interbreed

Question 25

hybrids are...

Answer 25

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

Question 26

Reinforcement

Answer 26

accelerates isolation after secondary contact. promotes evolution of prezygotic isolation

Question 27

Sympatric speciation

Answer 27

populations are not geographically or environmentally separated. not very common

Question 28

Polyploidy in plants

Answer 28

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.

Question 29

Allopolyploidy in plants

Answer 29

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

Question 30

speciation

Answer 30

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