3.3 Biodiversity and variation. Flashcards
What levels can biodiversity occur on?
It can exist within an ecosystem, with a species and within individual genes?
What is ecosystem diversity?
It is the variety habitats, biological communities and ecological processes that occur in the biosphere.
What is species diversity?
It is the number of different species within an ecosystem.
What is genetic diversity?
Variation of genetic characters within a single species.
Why is genetic diversity important?
It allows organisms to adapt to certain conditions allowing increased survival.
What is mutation?
Mutation is the source of genetic variation.W
What do mutations do?
They change the characteristics of organisms.
e.g white mouse > black mouse.
What is an adaptation?
An adaptation is a special feature or characteristic that improves an organism’s chance of survival.
What are the different types of adaptations?
structural adaptations (such as hair to keep warm or the colour of a moth)
behavioural adaptations (such as courtship display to attract a mate)
physiological adaptations (such as the ability to produce concentrated urine to conserve water)
(From JacPlus)
What is an allele?
An allele is an alternate form of a gene (found in the same place in the chromosome).
How can variation occur during meiosis?
It can occur due to:
- The independent assortment of chromosomes
- The ‘crossing over’ of maternal and paternal chromosomes.
(JacPlus 3.3 has a good diagram (source 3.14 and 3.15))
What is a genotype?
The genotype is the combination of alleles for a particular trait within an individual.
What is a gene pool?
It is the alleles for a particular trait within a population.
What is gene flow?
The movement of individuals and their alleles between populations.
What is genetic drift?
It is the changes in allele frequency due to chance events such as floods and fires.
What is natural selection?
The process where organisms better adapted for an environment are more likely to pass their genes on to the next generation.
What can impact allele frequencies?
Natural selection and genetic drift.
Explain gene flow.
It is when certain organisms move out (emigration) or move in (immigration) which either removes alleles from a population or adds new alleles to a population.
Which reproductive technologies unbalance natural levels of biodiversity?
Artificial selection, artificial insemination, IVF and cloning.
How does artificial selection (selective breeding) reduce biodiversity?
It makes it so its likely that only some (wanted) traits are passed on.
How does artificial insemination reduce biodiversity?
Only males with wanted traits will have their sperm sampled.
How does IVF reduce biodiversity?
Embryos are chosen meaning natural process is lost.
How does cloning reduce biodiversity?
Creates more copies of certain alleles.
What are the consequences of reduced biodiversity?
Extinction. When an environmental change or threat occurs there will be no variation that allows some species to survive. Some species won’t survive to reproduce.
