biodiversity Flashcards
(43 cards)
what is classification?
the organisation of living organisms into groups
what is taxonomy?
the theory and practice of biological classification
what is artificial classification?
- based on analogous (visible) characteristics
- not based on evolutionary relationships
give some examples of artificial classification:
- colour
- size
- wings?
what is phylogenetic classification?
- based on shared features from their ancestors
- based on evolutionary relationships
gives an example of phylogenetic classification:
limbs in mammals have similar structures
what is an analogous structure?
they have the same function but could have very different ancestors
what does homologous mean?
when organisms have similar evolutionary origins/structures regardless of function
what 2 groups are used to form a binomial name?
genus and species
what are the 4 kingdoms in a eukarya?
- protocrista
- fungi
- plantae
- animalia
what are some features of archea?
- single celled prokaryotes
- similar shape/size to bacteria
- genes and protein synthesis similar to eukaryotes
- no murein in their cell walls
- more complex form of RNA polymerase for transcription and translation
what are the positives of identifying organisms by their physiological features?
- easy
- cheap
- does not require advanced equipment
what are the negatives of identifying organisms by their physiological features?
- may look similar but may not be at all
- patterns of inheritance not clear
- genes are polygenic e.g human height
- may be a result of similar environment not evolutionary relationships
how can we get more accurate definition of a species?
by comparing:
- DNA or mRNA base sequences e.g the exact order of nucleotides
- amino acid sequence in proteins
what do DNA base sequences allow us to do?
- determine the exact order of nucleotide bases
- determine how diverse organisms are
- show that a mutation=new species
what are the negatives of DNA base sequencing?
- can be expensive
- can be time consuming
what does comparing amino acid sequencing allow us to do?
- can determine the order of DNA and mRNA
- show that the similarity of amino acid sequence=similarity of species
what are the negatives of amino acid sequencing?
- expensive
- time consuming
- some DNA will be non-coding
describe the process of DNA hybridisation:
- heat to separate strands of DNA (by breaking hydrogen bonds)
- cross combine the single strands of DNA
- cool to allow the hydrogen bonds to reform (renaturation)
- determine the degree of hybridisation
what do different degrees of hybridisation represent?
- complete hybridisation=identical organisms
- partial hybridisation=organisms partially related
- no hybridisation=organisms unrelated
how can we tell how many hydrogen bonds have reformed in DNA hybridisation? what does this show?
- increase the temperature more and record the temperature needed to separate 2 strands
- higher temp required=greater no. of hydrogen bonds formed=greater similarity in DNA=closer related the species
name 3 factors that reduce biodiversity:
- deforestation
- polluting rivers/lakes/oceans
- global warming
- hunting and farming
how does agriculture affect biodiversity?
- monoculture-growing only one species
- lack of intercropping-reducing species grown
- competition for space-habitats cannot grow and there is thus not enough space for all species
- use of pesticides and fertilisers-kills insects and smaller animals/enters water cycle
- cattle-release of methane (ghg)/trampling/overgrazing
- draining wetland and marshes- destroys habitats and removes nutrients
- removing hedgerows-kills animals living in them
how does deforestation affect biodiversity?
- 50,000 species lost every year due to deforestation
- direct loss of species
- loss of habitats lead to loss of species
