TOPIC 7.3-7.4 evolution may lead to speciation + pop in ecosystems Flashcards
sympatric speciation
Not geographically isolated - occurs in same pop.
Reproductive isolation - cannot breed to produce fertile offspring.
Changes in allele freq
Diff alleles passed on
Gene pools remain separate
Disruptive selection
allopatric speciation
No interbreeding as geographic isolation
Separate gene pools
Variation due to mutation
Different selection pressures –> Selection for diff adv features. selected organisms survive & reproduce.
Different reproductive success –> Change/inc in allele freq
Adapted organisms breed
mark-release-recapture method
Capture sample, mark and release
Method of marking doesnt harm/ make visible to predators.
Leave sufficient time for them to ran distribute before collecting a second sample.
Pop = num in 1st sample × num in 2nd sample divided by num of marked in 2nd sample
population of trees in the forest evolved adaptations to the mountain environment.
Use your knowledge of selection to explain how (3)
Variation in org colonisers
Some better (adapted for) survival (in mountains)
Greater reproductive success
Allele freq change
succession
Colonisation by pioneer species which change env conditions and make it less hostile for new species eg. provide food for other species
New species colonise once theres a change.
Other species eaten/ outcompeted as sucession continues.
Inc biodiversity to climax community (final/stable community) = abiotic factors constant
population
organisms of one species in a habitat
community
organisms of all species in a habitat
predator prey relationship
prey pop inc = more food for predator so predator pop inc –> more prey killed so prey pop dec
less food for predator = predator pop dec so less prey killed = prey pop inc
interspecific competition
diff species
intraspecific competition
same species
niche
role of species in its habitat. unique (adv) bc less competition for food/resource
