Speciation

Question 1

Define Speciation

Answer 1

Mechanism by which new species originate from existing ones

Question 2

What are the 2 main points of the biological species concept and what are the 2 limitations

Answer 2

Organisms that have the potential to interbreed and produce viable, fertile offspring
Cannot be applied to asexual organisms and cannot be applied to extinct organisms

Question 3

What is the morphological species concept and what is 1 limitation and 1 advantage

Answer 3

Define species based on measurable physical characteristics
Can be applied to asexual and sexual organisms
Is subjective

Question 4

What is the ecological species concept

Answer 4

Definition of species based on where they live and what they do

Question 5

What is the evolutionary/Phylogenetic species concept and what is 1 major advantage

Answer 5

Defines species based on unique genetic history - physical or molecular characteristics
Can classify extinct species from the fossil record

Question 6

Define these 5 pre-zygotic barriers
- Habitat isolation
- Temporal Isolation
- Behavioural isolation
- Mechanical isolation
- Gametic isolation

Answer 6

Habitat - 2 species living in 2 different habitats will not encounter eachother
Temporal - 2 species that breed at different times of the day or seasons
Behavioural - Lack of mate recognition due to different visual or auditory queues
Mechanical - Anatomical incompatibility - prevent sperm transfer
Gametic - Sperm of 1 species cannot survive in reproductive track of another

Question 7

Define these 3 post-zygotic barriers
- Reduced hybrid viability
- Reduced hybrid fertility
- Hybrid breakdown

Answer 7

RHV - Hybrid may abort development at embryonic stage
RHF - Offspring is viable but infertile
HB - 1st generation are viable and fertile but subsequent generations are defective

Question 8

What is Allopatric speciation

Answer 8

Speciation due to physical separation - separated gene pools diverge and maintenance of reproductive barriers form a new species

Question 9

What is a hybrid zone

Answer 9

A zone where 2 populations can interbreed hence geographic separation is not complete

Question 10

What is sympatric speciation and describe the 3 models of genetic isolation
- Polyploidy
- Sexual selection
- Habitat differentiation

Answer 10

Speciation within populations that occupy the same geographical area
Polyploidy - Mismatching numbers of chromosomes due to meiotic mistakes mean offspring cannot mate with parental species
Sexual -Mechanism that female uses to choose mate can determine or contribute to pre-zygotic isolation
Habitat - More than 1 type of habitat leads to different adaptations