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Description
Flashcards by Olivia McKenzie-Allen, updated more than 1 year ago
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Created by Olivia McKenzie-Allen
over 8 years ago
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| Question | Answer |
| what is a species? | organisms which are capable of successfully breeding to produce fertile offspring |
| what is meant by the binomial system of naming organisms? | species are named with the generic and te species name to prevent confusion between names of organisms |
| why is the courting behaviour of species important? | - to recognise members of their own species to ensure mating only occurs between members of the same species - to identify a mate capable of breeding as both partners need to be mature and fertile - form pair bond to mate and raise offspring - synchronise mating to give maximum possibility of sperm and egg meeting - to bring the partner into a physical state capable of breeding |
| what are the two types of taxonomic classification? | artificial classification and phylogenic classification |
| how does artificial classification work? | organisms are divided into groups according to visible differences such as colour, size number of legs etc. these may not be reliable, as while the characteristics are the same they may not have the same evolutionary origins |
| what are analogous characteristics? | characteristics with the same purpose but different evolutionary origins such as the wings on birds and butterflies. |
| how does phylogenetic classification work? | - based on evolutionary relationships between organisms and their ancestors. - classifies species into groups using shared features from ancestors - arranges groups into a hierarchy in which groups fit into larger groups with no overlap |
| what are the three domains called in taxonomy? | eukarya, bacteria, and archea |
| what features do bacteria have? | - no membrane bound organelles - unicellular - 70s ribosomes - have cell walls made of murien - single loop of DNA without histones |
| what features do archea have? | - unicellular - membranes contain fatty acid chains joined by ester linkages - protein synthesis similar to eukaryotes - no murien in cell walls - have a complex form of RNA polymerase - 70s ribosomes |
| what features do eukarya have? | - have membrane bound organelles - have membranes containing fatty acids attached to glycerol by ester linkages - larger 80s ribosomes |
| what order do taxonomic groups come in? | domain kingdom phylum class order family genus species |
| define species diversity | number of different species and the number of individuals of each species within any one community |
| define genetic divesity | the variety of genes possesed by the individuals that make up a proportion of a species |
| define ecosystem diversity | the range of different habitats from small local habitats to the whole earth |
| define species richness | the number of different species in a particular area at a given time |
| how do you measure index of species diversity? | d = (N(N-1)) / sum of(n(n-1)) where: d = diversity index N = number of organisms of all species n = total number of organisms of each species |
| what does a low index of diversity mean? | that conditions are harsh so few species survive |
| what does phylogeny show? | the evolutionary relationship between organisms |
| define community | all organisms in an environment at a given time |
| define ecosystem | all living an non-living components of a particular area |
| define allele | different versions of the same gene |
| define biomass | total mass of living matter usually measured over a particular area in a particular time period |
| define habitat | place where an organism usually lives, characterised by physical organisms and other present organisms |
| define environment | the natural surroundings of an organisms habitat |
| define biodiversity | how many different genes, species and habitats in a location |
| what are the two ways in which species diversity can be reduced due to farming? | direct and indirect |
| how can we prevent the loss of species diversity due to farming? | conservation methods |
| what are examples of direct loss of species diversity? | - removal of hedgerows - creating mono-cultures by replacing natural meadows with crops - filling in ponds and draining wetlands |
| what are examples of indirect loss of species diversity? | - use of pesticides and inorganic fertilisers - escape of silage from slurry tanks into water courses - absence of crop rotation |
| what are some methods of conservation? | - plant hedges as boundaries rather than fences - maintain existing ponds - leave wet corners of fields rather than draining them - reduce use of pesticides by using biological control where possible |
| why is looking at physical characteristics unreliable when calculating genetic diversity? | because characteristics are coded for by more than one gene, and some characteristics are changed by the environment |
| how do we look at genetic diversity through DNA analysis? | each base is tagged with a different fluorescent dye and tested by computers to show the sequence. this can also look at evolutionary relationships between species |
| by what methods can wecompare species diversity? | - genetic analysis - mRNA analysis - comparing polypeptide chains |
| what is the best method of investigating diversity? | by looking at DNA bases because amino acids can be coded for by multiple base triplets so may be inconclusive |
| what is random sampling? | taking measurements or individuals in the population being investigated from random areas to ensure the most reliable possible result is gained |
| what is sampling bias? | an unconscious decision made about where to take a sample from depending on the hypothesis |
| why can chance cause problems in random sampling? | the individuals chosen may all coincidentally have the same characteristics even though |
| how can you ensure sampling is random? | 1. place tape measures at right angles to each other in the investigation area 2. use a random number generator to get coordinates to place a quadrat 3. take samples at the coordinates |
| how does a large sample size increase reliability? | the more individuals selected, the less chance that chance will influence the results |
| define inter-specific variation | any differences between different species |
| define intraspecific speciation | differences between members of the same species |
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