Chapter 8.5 - Speciation

Question 1

What is Speciation?

Answer 1

The formation of a new species

Question 2

Microevolution

Answer 2

small changes in gene (allele) frequencies and phenotypic traits within a population and species

Question 3

What are the modes of speciation?

Answer 3

reproductive isolating mechanism
prezygotic mechanism
postzygotic mechanism

Question 4

postzygotic mechanism

Answer 4

a reproductive isolating mechanism that prevents maturation and reproduction in offspring from interspecies reproduction

Question 5

prezygotic mechanism

Answer 5

a reproductive isolating mechanism that prevents interspecies mating and fertilization (for example, ecological isolation, temporal isolation, and behavioural isolation)

Question 6

reproductive isolating mechanism

Answer 6

any behavioural, structural, or biochemical trait that prevents individuals of different species from reproducing successfully together

Question 7

Types of Speciation

Answer 7

Allopatric and Sympatric

Question 8

Sympatric

Answer 8

When a new species evolves within a large population due to reproductive isolation
Commonly caused by genetic changes such as mutations and polyploidy (extra set of chromosomes)

Question 9

Allopatric

Answer 9

Occurs when a population is geographically divided into isolated subpopulations
Over time, these groups evolve independently, and form new species
Eventually members of the different populations
can no longer interbreed even if they come back into contact.

Question 10

Human Influence?

Answer 10

Human activities like
Agriculture expansion
Construction on roads etc
Can cause large habitats to move into smaller areas
human activities influence the evolution of new species

Question 11

What are the types of isolation?

Answer 11

behavioral, temporal, ecological, mechanical, gametic

Question 12

behavioral isolation

Answer 12

different species use different courtship and other mating clues to find and attract males

Question 13

temporal isolation

Answer 13

different species breed at different times of the year

Question 14

ecological isolation

Answer 14

very similar species may occupy different habitats within a region

Question 15

mechanical isolation

Answer 15

differences in morphological features may make 2 species incompatible

Question 16

gametic isolation

Answer 16

male gametes may not be able to recognize and fertilize an egg of a different species

Question 17

Postzygotic/ after fertilization different types:

Answer 17

zygotic, hybrid unviability, hybrid infertility

Question 18

zygotic mortality

Answer 18

Mating and fertilization is possible but genetic differences result in a zygote that is unable to develop properly

Question 19

hybrid unviability

Answer 19

a hybrid individual develops but either dies before birth, or if born alive, cannot survive to maturity

Question 20

hybrid infertility

Answer 20

Hybrid offspring remain healthy and viable but are sterile