M4 CH11: biodiversity Flashcards
(36 cards)
define biodiversity
the variety of living organisms in a specific area
define habitat biodiversity
the number of different habitats in a given area
define species richness
the number of different species living in a particular area
define species evenness
the relative abundance of individuals of each species
define genetic biodiversity
the variety of alleles within a species
explain what genetic drift is
the loss of diversity over time by random chance
outline the importance of genetic diversity
creates a larger gene pool
more adaptations and survivals
resistance to biotic factors- disease
explain what a locus is
the position of a gene on a chromosome
explain the term natural selection
- reproduction creates more individuals than the environment can support.
- competition for food occurs as a consequence
- limited food acts as a selection pressure for organisms
- individuals with favourable phenotypes have a selective advantage
- these organisms outcompete others for food, and survive and reproduce
- these favourable alleles are passed onto future generations
state 3 causes of low genetic diversity.
- genetic bottleneck event
- the founder effect
- genetic drift
state the factors affecting genetic biodiversity.
mutations
natural selection
genetic bottlenecks
founder effect
genetic drift
gene flow
explain what a genetic bottleneck is.
natural disaster
causes a large decrease in population size
reduces the gene pool
results in reduced genetic variation
explain what the founder effect
when a few individuals of a species take over a new area, their offspring experience a loss in genetic variation. this results in rarer alleles becoming more common in the population.
explain what genetic drift is
random fluctuations in the frequencies of alleles between generations
can cause some traits to become dominant, some to disappear
explain why genetic drift is more pronounced in small populations.
because the gene pool is smaller
explain what gene flow is
the transfer of alleles from one population to another when individuals of one population migrate
state some human activities which have changed the genetic diversity of organisms
selective breeding
captive breeding
cloning
explain what genetic polymorphism is
genes which have multiple alleles
explain what a polymorphic gene is
a gene with more than one allele
synoptic: state the name of the process that can be used to separate DNA fragments based on their size. explain the process.
electrophoresis
add expln
give the equation to calculate the proportion of polymorphic gene loci
number of polymorphic loci / total number of loci
state the 2 types of sampling that can be used.
random
non random
state the most appropriate equipment to gather a random sampling of flying organisms
sweeping nets
explain what pitfall traps are
what type of sampling
what organisms are gathered in them
cans/jars buried in the ground
random sampling method
small ground-bound organisms