topic four redone ! Flashcards
(24 cards)
spec point 4.1
Know that over time the variety of life has become extensive but is now being threatened by human activity.
!what is the meaning of biodiversity
the variety of living organisms within an ecosystem
!what is the meaning of endemism
a species is found exclusively in a particular geographical location
!ecosystem definition?
A biological community of interacting organisms.
community definition
all different populations of species living and interacting in a particular habitat
population definiton
organisms of the same species living together within an area
Species definition ?
organisms which cannot interbreed to produce fertile offspring count as different species
species richness definition
The number of different species found in a particular area or community
how can biodiversity be measured within a species itself
by calculating the heterozygosity index which is number of heterozygotes over the number of individuals in the population
how can biodiversity within different habitats be compared
Index of diversity
N= total number different species
ZIG ZAG =Sum of
n= number of organisms within EACH species
explain the concept of niche
The specific unique role an organism plays in a community
what are the thee main types of adaptations
Behavioural adaptations: Change to how an organism responds to and external stimuli.
Physiological adaptations: cellular and molecular changes on an internal metabolic level anatomical adaptations: Changes to physical feature of an organism
how can natural selection lead to adaptation and variation
Variation in a population due to mutation
selection pressure upon organisms
better adapted organism survive and breed
they pass their advantageous alleles to offspring
results in change in allele frequency and change in genes pool
what is a gene pool
A gene pool is the collection of all the genes, including their various alleles, present within an interbreeding population of a species at a specific time. It represents the total genetic variation within that population.
Describe the hardy Weinberg equation and why it is used ?
Used to show wether a change in allele in occurring over time in a population ( evidence for evolution trough natural selection
requires if p+q=1 ( they do not give this)
allele frequency meaning ?
how common a specific version (allele) of a gene is within a population of the same species
what is speciation and how can It occur
development of a new species which can occur when populations are reproductive isolated
types of geographical isolation
behavioural isolation
temporal/ seasonal isolation
what is behavioural isolation
Species having different behaviour which isolate them e.g. birds having different songs
species can breed during different seasons, eyes and time of the day. if some species do not have the same breeding times that causes isolation
mechanical isolation
Mechanical isolation occurs when differences in the size or shape of reproductive organs prevent successful mating or pollination
habitat isolation
changes in habitats
