chapter 14 pt 1

Question 1

species

Answer 1

a group of organisms whose members have the potential to interbreed in nature and produce viable, fertile offspring

Question 2

Population

Answer 2

group of organisms of the same species of a defined area

Question 3

What is the biological species concept based on?

Answer 3

The potential to interbreed rather than physical characteristics

Question 4

Speciation

Answer 4

the formation of new species, occurs when some individuals can no longer interbreed with the rest of the group

Question 5

Prezygotic Barriers

Answer 5

impedes mating between species or hinders fertilization of ova if members of different species attempt to mate

Question 6

Postzygotic barriers

Answer 6

prevents the hybrid zygote from developing into a viable, fertile adult

Question 7

What are the 5 prezygotic barriers?

Answer 7

1. Habitat Isolation
2. Behavioral Isolation
   3.Temporal Isolation
3. Mechanical Isolation
4. Gametic Isolation

Question 8

Habitat Isolation and example

Answer 8

different environments, ladybugs feed on different plants

Question 9

Temporal Isolation and example

Answer 9

Active or fertile at different times, ex. crickets

Question 10

Behavioral Isolation

Answer 10

Different courtship activities, ex. frog mating calls

Question 11

Mechanical Isolation

Answer 11

Mating organs are incompatible, ex. Sage species use different pollinators

Question 12

Gametic Isolation

Answer 12

Gametes can not unite, ex. sea urchin gametes are incompatible

Question 13

What are the 3 postzygotic barriers?

Answer 13

1. Reduced hybrid viability
2. Reduced Hybrid fertility
3. Hybrid breakdown

Question 14

Hybrid viability and example

Answer 14

hybrid offspring fail to reach maturity, ex. hybrid eucalyptus seeds and seedlings are not viable

Question 15

Hybrid infertility and example

Answer 15

hybrid offspring are unable to reproduce, ex. liger

Question 16

Hybrid breakdown and example

Answer 16

Second-generation hybrid offspring have reduced fitness, ex. hybrid mosquitos have abnormal genitalia

Question 17

Allopatric speciation

Answer 17

a population forms a new species while geographically isolated from its parent population, has to be a small population, so it can be influenced by genetic drift and natural selection

Question 18

Example of allopatric speciation

Answer 18

Galapagos tortoises were genetically separated, therefore formed new species and squirrels in the Grand Canyon

Question 19

Sympatric Speciation

Answer 19

Populations diverge genetically while sharing the same habitat, usually plants

Question 20

How does sympatric speciation occur?

Answer 20

A failure of cell division can double a cell’s chromosome number, asexual reproduction makes many and then these can interbreed

Question 21

Polyploid

Answer 21

offspring with more chromosomes than either parent, forms when gametes of two species unite and produce the first cell of a new species

Question 22

Punctuated equilibrium

Answer 22

long periods of little change are interrupted by bouts of rapid change, contrasts with gradual change

Question 23

What scientists came up with Punctuated equilibria?

Answer 23

Niles Eldredge and Stephen Jay Gould

Question 24

Adaptive Radiation

Answer 24

several species from one group whose adaptations allow them to fill vacant ecological niches; may follow mass extinctions

Question 25

Can speciation be rapid? Give an example

Answer 25

Yes, the sunflower Helianthus anomolous originated
from the hybridization of two other sunflower species

Question 26

How many genes change when a new species forms and give an example

Answer 26

Depending on the species in question, speciation
might require the change of only a single allele or
many alleles; for example, in Japanese Euhadra
snails, the direction of shell spiral affects mating and
is controlled by a single gene.

Question 27

When is a species extinct?

Answer 27

when all of its members have died

Question 28

Background extinction rate

Answer 28

the pace
at which species go
extinct due to
gradually changing
environments.

Question 29

Mass Extinctions

Answer 29

loss of 50% of species

Question 30

how many mass extinctions has Earth witnessed?

Answer 30

5

Question 31

251 Million Years ago extinction

Answer 31

 volcanic eruptions
 ash & lava, decrease in temps
 decrease in O2,
 advance of bacteria which emit toxin

Question 32

65.5 million years ago extinction

Answer 32

 extinction of ½ of marine life and the dinosaurs
 fossil records show layer of iridium in strata (often found in
meteors)
 Cloud could have blocked sunlight for several months
 The Chicxulub crater off the coast of Mexico is evidence of a
meteorite that dates to the same time (Impact Theory)

Question 33

Impact Theory

Answer 33

Suggests that meteorites or comets caused some
mass extinctions

Question 34

cenozoic era

Answer 34

followed a mass extinction, mammals

Question 35

Who was responsible for redefining the work of Darwin and Linnaeus when defining a biological species?

Answer 35

Ernst Mayr

Question 36

Parapatric speciation

Answer 36

species share the same border, new species enters a habitat bordering parents species