evolution. Flashcards
(6 cards)
why does a gene with is has a d9ominant allele increase rapidly
allele is dominant so only one allele needed for gene to be expressed
symmetric speciation with trees of different flowering times
- Occurs in the same habitat / environment / population;
- Mutation/s cause different flowering times;
- Reproductive separation / isolation
- Different allele/s passed on / selected
- Disruptive (natural) selection;
- Eventually different species cannot (inter)breed to produce
fertile offspring;
allopatric speciation
1.mutation causes variation
2.allopatric speciation geographically isolated
Reproductively isolated
3.different selection pressures
4.different alleles passed on changing allele frequency
5. can no longer reproduce fertile offspring
The mark-release-recapture method can be used to estimate the size of a
fish population
Capture/collect sample,
Ensure marking is not harmful
Allow (time for) fish to (randomly) distribute before
collecting a second sample;
(Population =) number in first sample × number in second
sample divided by number of marked fish in second
sample/number recaptured;
Succession occurs in natural ecosystems. Describe and explain how
succession occurs.
- (Colonisation by) pioneer species;
- Pioneers/species/organisms change the
environment/habitat/conditions/factors; - (Environment becomes) less hostile for other/new species
- Change/increase in diversity/biodiversity;
- (To) climax community;
Describe how you could estimate the size of a population of sundews in a
small marsh.
use 2 tape measures at 90 degrees
random generator for coordinates
count frequency in quadrat
large sample and mean