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Define Taxonomy.
Describing, naming and classifying organisms.
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How are species ordered?
Hierarchal system - levels of increasing similarity
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What are phylogenetic relationships?
Evolutionary lines linking species
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Why use a binomial naming system?
Every species gets a unique combination of two names. One =genus. One=species . Able to see which species are most directly related to each other.
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What are the current groups at the top of the hierarchy?
Domains- Bacteria, Archae, Eukarya
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How are Bacteria, Archaea and Eukarya grouped together?
Comparing the genetic sequences of their ribosomal DNA
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What do viruses not fit within the current hierarchial system?
Viruses- Outside mainstream classification- (replicate only within hijacked living cell).
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Why do lichens not fit within the 3 domains classification system?
Belong to more than one genotype (Chimeras) - close association of fungal+algal cells. Classified on basis of fungal partners as sometimes more than one species of algae can be involved.
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What do all eukaryotes have in common?
DNA wound around proteins within a nuclear membrane.
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What are monerans?
Species with no distinct nucleus e.g Bacteria, Archaea.
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What is the Endosymbiant theory as proposed by Lynn Margulis?
Organelles e.g. chloroplasts + mitonchondria = derived from prokaryotic cells that combined symbiotically with a host cell. =eukaryotes with membrane-bound organelles. Explains- own DNA + similar size to photosynthetic/chemosynthetic bacteria
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What could make classification using shared morphology difficult?
Polymorphic species. Convergent evolution can occur- natural selection produces species with similar features- Homoplasy.
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What is an apomictic species?
One that can produce seed without being pollinated.
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Why is comparing protein compositions key in identifying species?
Some proteins=present in most organisms e.g. Cytochrome (in all living organisms for energy generating in mitochondria + chloroplasts) first 33 amino acids=same. then different order in each species.
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How is DNA fingerprinting carried out?
Using PCR (polymerase chain reaction). - Amplify DNA fragments with tagged bases. The more fragments that are shared by two species /individuals the closer they are related.
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What else can be analysed from a plant to determine its species excluding DNA?
Scent/chemical signals used to attract pollinators etc. Most species are different chemotypes.
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What is the ecological species concept?
Where you recognise a species by its role in the environment.
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What does the distribution of most species look like on a graph?
Normally distributed- species have an optimum range with most individuals close to the mean value.
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Why are most species normally distributed on a graph of range?
Because most are adapted to specific conditions. The further away from the optimum-the less favorable the conditions are.and the higher the physiological costs.
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When might it be an advantage to have different adaptations to the norm?
Possible resistance to a strain of disease, changing environmental conditions etc.
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What is a neutral variation?
When there is no selective advantage or cost.
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What are generalist species?
Where species can occupy a wide variety of ecological roles and environments- able to exploit many different resources. Good strategy in unpredictable habitats.
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What are specialist species?
Highly adapted and efficient in exploiting specific resource/s. Will outcompete others for the resource however will do badly if environmental conditions change too rapidly.
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What is a niche overlap?
When two species occupy the same part of the resource spectrum.
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What is the fundamental niche?
The range absent from interference from other species.
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Define: allopatic speciation
Separation by space
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Define: sympatric speciation
Incompatible gene pools
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What are the types of reproductive barriers? List some examples.
Pre-zygotic- Mechanical, behavioural, physiological. Post-zygotic-mismatch in number of chromosomes.
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Is polyploidy more common in animals or plants?
Plants. Rarely produces viable or fertile offspring in animals.
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What is polyploidy?
Where gametes have multiple copies of chromosomes. There are not haploid.
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What happened to the common bend grass races growing on abandoned copper mines in North Wales?
Metal-tolerant-lives in marginal land due to: Parapatric speciation- Small, isolated and rapidly reproducing population= inbreeding-highly adapted populations n discrete and distinct habitats.
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How many plant cultivars is there predicted to be? And from how many wild species?
70,000 from around 1,100 wild.
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Examples of GM crops?
Round-up ready soya
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What solution could prevent the formation of superweeds from cross-over between wild plants and GM crops?
Engineer the genes on the chloroplasts so they can only be passed down the maternal line- no species cross-over?
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What is an ecological problem of genetically modifying crop species to produce their own pesticides? Example.
Non-target species affected. E.g Monarch butterfly larvae are poisoned by the Bt toxin plants that have an endotoxin gene from Bacillus thuringiensis.
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Card 2


How are species ordered?


Hierarchal system - levels of increasing similarity

Card 3


What are phylogenetic relationships?


Preview of the front of card 3

Card 4


Why use a binomial naming system?


Preview of the front of card 4

Card 5


What are the current groups at the top of the hierarchy?


Preview of the front of card 5
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