| what has happened to the variety of life on Earth over time? | over time the variety of life on Earth has become extensive but is now being threatened by human activity |
| biodiversity | the range of species in a habitat
the genetic diversity within a species |
| endemism | the state of a species being unique to a particular geographic location and found nowhere else |
| how is biodiversity measured within a habitat? | species richness
genetic diversity within a species |
| heterozygosity index | H = number of heterozygotes/number of individuals in the population |
| biodiversity index | D = N(N-1)/Σn(n-1)
D = biodiversity index
N = total number of organisms from all species
n = number of individuals in a species |
| niche | the role of an organism within its community |
| three types of adaptations | anatomical
behavioural
physiological |
| anatomical adaptations | structural/physical features of an organism that helps it survive |
| behavioural adaptations | how organisms behave in order survive |
| physiological adaptations | internal processes that occur in an organism which helps it survive |
| natural selection | the process by which better adapted individuals to the environment survive and pass on advantageous alleles to future generations |
| evolution | the process by which the frequency of alleles in a gene pool changes over time as a result of natural selection |
| adaptation | an alteration of any part of an organism's structure or function as a result of natural selection
the organism becomes better fitted to survive and reproduce in its environment |
| how can natural selection lead to adaptation and evolution? | a variety of phenotypes exists due to a mutation
environmental changes occur and selection pressure changes
some individuals posses advantageous alleles giving them a selective advantage allowing for survival and reproduction
advantageous alleles are passed on to their offspring
over time the frequency of alleles in a population changes |
| Hardy-Weinberg equation | p² + 2pq + q² = 1
p +q = 1
p² = dominant allele
2pq = heterozygous allele
q² = recessive allele
p = frequency of dominant allele
q = frequency of recessive allele |
| what is the Hardy-Weinberg equation used for? | estimate the frequency of alleles in a population
monitor changes in allele frequency over time |
| conditions of the Hardy-Weinberg equation | no mutations
no selection pressure
large population
isolated population
random mating |
| reproductive isolation | the accumulation of different genetic information in populations due to different environments and selection pressures |
| types of reproductive isolation | allopatric
sympatric |
| allopatric | groups of organisms that are geographically isolated |
| sympatric | organisms are isolated by other factors but within the same area |
| classification | the way of organising the variety of life based on relationships between organisms using differences and similarities in phenotypes and genotypes
it is built around the species concept |
| classification order | domain
kingdom
phylum
class
order
family
genus
species |
| 3 domains | Eukaryote
Bacteria
Archaea |
| 5 kingdoms | Animal
plants
fungi
protists
prokaryotes |
| species | a group of organisms that can reproduce with one another to produce fertile offspring |
| taxonomy | the science of naming, describing and classifying organisms |
| molecular phylogeny | the analysis of molecular differences in DNA and proteins of different organisms to determine how closely related organisms are |
| why is the process of critical evaluation of new data important to the scientific community? | data obtained by molecular phylogeny has been accepted by scientists giving rise to new taxonomic groupings - the three-domain model of classification
scientist publish their findings in public journals and present them at conferences where the scientists would study the evidence by peer review |
