Selection And Evolution Flashcards
Suggest assumptions that must be made for the mark-release-recapture method to be valid.
Marking not harmful / cannot be removed;
Constant population size;
No births / deaths or no immigration;
Sufficient time for marked individuals to mix with rest of population;
Mobile
Suggest ways by which CITES (Convention on International Trade in Endangered Species) attempts to regulate the trade in wild fauna and flora.
Trade ban;
If species not at risk of extinction, permit required;
Application of border controls / checks;
Provide countries with lists of species that are rare / endangered;
Encourages governments to join CITES / to abide by CITES regulations
Outline how vigorous, uniform varieties of maize were developed by selective breeding.
Breed plants with desired characteristics;
Breed better offspring repeatedly / for many generations;
Inbreeding (breeding of same species that have close relations);
F1 (first offspring of a monohybrid cross) have same genotype / uniform phenotype;
Define the term heterosis (hybrid vigour).
The tendency of a cross-bred individual to show qualities superior to those of both parents
What are the main reasons for reproductive isolation?
No gene flow / interbreeding between populations;
Different selection pressures;
Different mutations;
Natural selection;
Genetic drift;
Change in gene pool;
Leads to different morphological / behavioural / physiological features;
Allopatric speciation
Scientists found that when prairie strips formed 10% of a crop-field:
-soil erosion decreased by 95%
- mineral loss from the field decreased by 90% fro phosphorus compounds
-mineral loss from the field decreased by 85% for nitrogen compounds
Evaluate the economic effects of prairie strips on farming.
Negative:
Smaller crop area so lower yield;
Prairie strip insects may feed on crop;
So less profit / income
Positive:
Soil more fertile so higher yield;
Less / no fertiliser used;
So more profit / income OR reduction in expense
