Speciation

Question 1

define speciation

Answer 1

formation of a new species which are genetically distinct to the older ancestral species

Question 2

define extinction

Answer 2

permenant loss of all member of a species

Question 3

how are speciation and extinction related

Answer 3

speciation increase biodiversity and extinction decrease
when extinction occurs there is less competition and more speciation occurs= balance

Question 4

define geographical isolation

Answer 4

formation of a new species as a result of whole/ part of the species being split by a geographical barrier from ancestral species

Question 5

explain geographical speciation (8)

Answer 5

population of a single species separated by geographical barrier (river, sea, mountain)
population split in two
there is no gene flow between populations
each region will have its own environment and each exposed to different
therefore natural selection occurs independently in each as certain environments require certain characteristics
individuals from each are genotypically and phenotypically different
when mix and cant interbreed and new species formed

Question 6

explain finches, tortoise, baobabs and proteas?

Answer 6

finches by strong winds to islands, varying foods and no competition
on each island different feeding result in certain beaks through natural selection
tortoise by current- varying food and no competition some domed and short necks due to wetlands and lots of food while some saddlebacked and short necks due to less food
baobabs- fruits from madagascar to africa- different necta (bats in africa) and lemur and moths in madagascar
proteas- gondwanaland split resulting in proteas species split- Aus and SA
proteas evolved in different conditions and became drought resistant, germinate during fire

Question 7

reproductive isolation definition

Answer 7

mechanism preventing two or more species from exchanging genes

Question 8

4 ways reproductive isolation occurs

Answer 8

• breed at different times
• courtship behaviour
• different pollinators
• infertile offspring
• preventing fertilization by different organ structures