6.1.2 Flashcards
Start of A
What is interspecific variation?
variation between 2 DIFFERENT species
What is intraspecific variation?
variation between the same species
What can cause variation?
genetic differences, influence of the environment
What is an example of discontinuous variation?
blood type
What us an example of continuous variation?
height/mass
What is continuous variation?
individuals in a population
vary within a range
no distinct categories
quantitative
What is discontinuous variation?
2 or more distinct categories no intermediates everyone falls into a category
monogenic influence and without environmental influence
What type of variation is diet in animals an example of?
continuous variation (has both genetic and environmental factors)
What are examples of genetic and environmental contributions to phenotypic variation?
diet in animals
etiolation
Why do plants do etiolation?
to reach sunlight
End of a
Start of B
What does polymorphic mean?
more than 1 phenotype for most characterisitics
What is artificial selection?
selection of a plant / animal with the desirable characteristics is chosen by the farmer / breeder and are bred together so the offspring have the desired trait
How would you do artificial selection with a cow?
need good quality milk
farmer should select with large yield of milk
breed with a bull with a family history of large yield of milk
select the offspring who have a large yield of milk and breed with others with a large yield of milk
repeat over many generations
desired characteristics become more dominant
What are disadvantages to selective breeding to animals?
restricts movement / mobility issues
heart issues
What issues with selective breeding?
- decreases the gene pool
- leads to more homozygous recessive disorders
- breeders select animals/plants based upon looks not health
- desired trait may be inherited with an undesired trait that could cause disease
What is linkage?
genes are found on the same chromosome
so are more likely to be inherited together
What is genetic drift?
random change in allele frequency of alleles over time
How does each generation differ from the parental allele?
random variation caused when creating gametes
What happens over time to alelles because of genetic drift?
some alleles lost and others inc in freq
What is the impact of the genetic drift?
impacts on smaller populations more as rare alleles are more likely to be randomly lost
dec genetic diversity
What is a genetic bottleneck?
massive reduction in population size through natural disaster
causes big reduction in gene pool
What happens because there is a reduction in the gene pool?
dec chance of survival from disease
higher impact of genetic drift
more unstable population
What are examples of genetic bottlenecks?
northern elephant seal
cheetah
What is the founder effect?
few organisms from a new population start a new pop and therefore there are only a small number of different alleles from the initial gene pool
What happens to the new pop due to the founder effect?
will grow with reduced genetic variation and will be more influenced by genetic drift
What disorders are you more likely to find in small pop from founder effect?
recessive
What do you do if the significant difference is not present?
null hypothesis accepted
What do you do if there is no significant difference present?
null hypothesis is rejected
What is a species?
organisms that can breed together to produce fertile offspring
What is sepciation?
formation of new species through evolution
What events lead to speciation?
members of pop become isolated
mutation arrises in 1 pop
passed onto offspring
inc in allele freq in pop
different pop no longer to breed together
occurs over many gen
What arises in population and can be passed onto offspring?
mutation
What happens whena mutation is passed onto offspring?
inc in allele frequency
What happens to the different populations when they try to breed after an inc in allele frequency in 1 pop?
no longer able to breed together
Why can species no longer breed together?
allopatric speciation
sympatric speciation
What is allopatric speciation?
geographical barrier physically separates 2 pop
pop evolve differently
over many gen species become so different cannot breed sucsessfully - distinct species
What is sympatric speciation?
org live in same place but have diff barriers that prevent interbreeding
What is an example of sympatric speciation?
different courtship behaviours
seasonal
different breeding seasons
diff times of day for breeding
mechanical issues
incompatability of genitilia
incompatbility of gametes
I
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Isolation by ___
Random mutation in allele arises
Natural selection occurs
Different selection pressures
time to allow changes in population to prevent interbreeding
What is epistasis?
gene of 1 loci affects expression of gene at another loci
