A4 unity and diversity of ecosystems Flashcards
biological evolution
change in the heritable characteristics (rooted in DNA) of a **population
what does it mean fro a theory to be falsified
it is shown that it is not true through the use of empirical evidence
three different molecular evidences for evolution
- DNA
- RNA
- Proteins
hox genes
the genes that play a role in determining your bodily developpement. These geners are incredibly similar across different types of organisms and would be hard to explain without a common ascestor and evolution
phylogenetic tree
a visual diagram that shows which species are most similar and related by comparing the similarity of a single gene
selective breeding
choosing organisms to mate together based on whether they have desirable characteristics
artificial selection
the result of selective breeding where organisms noe have combinations of traits that were not previously seen and have been curated by humans
homologous
structures
structures that share a similar internat structure despite being use for idfferent purposes (divergent evolution)
pentadactyl limbs
an example of homologous structres that is front or hind legs/arms that do or did have 5 digits
analogous structures
body parts that cary out the same function in different organisms but are structured differently internally (convergent evolution)
convergent evolution
when two species evolve independently but develop similar features and adaptations that suit their environment and become mroe similar
speciation
the formation of a new species by the splitting of an existing species (can no longer interbreed)
reproductive isolation
when populations can no longer interbreed with one another preventing gene flow (can be geographic, behavioral or temporal)
geographic isolation
there is a natural or man made barrier seperating males and females preventing mating
sympatric speciation
speciation that occurs when mating does not occur despite contact (casued by temporal or behavioral isolation)
allopatric speciation
physical geographic barrier leads to a lack of contact and the development of distincts species
behavioral isolation
accurs when the mate attracting actions of one group are different to those of another group
temporal isolation
organisms do not make due to them having different mating seasons or different times to release gametes
adaptive radiation
similar but distinct species rapidly evolve into different niches from a single or small number of species (can be a result of allopatric speciation)
what are the two things required for speciation to occurr
- reproductive isolation
- differential selection (different selection pressures)
hybridisation
the fertilisation of the fametes from one species by the gametes of another species
interspecific hybrids
organisms produced by cross breeding two different species to produce new varieties
polyploidy
when species have three or more copies of each chromosome due to errors in meiosis or hybridisation
autotetroploidy
the formation of a polyploid organism from members of the same species
allotetroploid
when a tetraploid organsism forms from the combining of gametes from two different species
abrupt speciation
when new species form withint a couple of generations as a result of tetrapoildy
biodiversity
the variety of living organisms and their interactions
species richness
a measure of the number of different species in an community
species evenness
a measure of how balanced an ecosystem is
gene pool
all the different alleles of a gene in a population
ecosystem diversity
the number of different biomes in an area or the number of mini ecosystems in a biome
species diversity
the number of unique species that exist within a community/habitat
genetic variation
the number of different alleles and gene combinations between members of the same species
five anthropogenic causes of speciation
climate change
habitat loss
invasive species
pollution
overharvesting
North Island Giant Moas (species)
extinct in New Zeland
haooened 500-1,000 years ago
overhunted by humans for food
carribean monk seals (species)
extinct in then carribean
50 - 100 years ago
overhunted for oil for lamps
dipterocarp forests (ecosystem)
dramatic ecosystem loss of forest coverage
ongoing issue
caused by logging for timber, clerance or palm oil plantations
meaning
in situ conservation effort
the management of biodiversity in the natural ecosystem/habitat
meaning
ex situ conservation effort
helping species and biodiversity outside their natural habitat/ecosystem
examples
in situ conservation effort
- active management to prevent human influence (nature parks/nature reserves)
- rewilging (removing/returning species)
- reclamation (replanting/reistablishment)
example
ex situ conservation effort
- zoo breeding programs with artificial insemination
- create habitats like botanic gardens
- seed and tissue banks
what prioritises conservation efforts
EDGE use ICUN status and genetic uniqueness
