biodiversity Flashcards
Define a species
A species is a group of organisms with similar phenotypes, which can breed to produce fertile offspring
Outline how species are named
Species are named using a binomial system, having a generic name (the genus) and a specific name (the species).
Describe courtship behaviour and explain its purpose
Courtship behaviour includes: displays, signals, gift bringing, calls. It helps animals to: recognise members of the same species, identify a mate that is capable of breeding, form a pair bond, synchronise mating, stimulate a physiological state to allow breeding.
Explain the principles of classification
Phylogentic classification groups organisms based on evolutionary relationships, shared features derived from ancestors and arrnages groups into a hierachy of decreasing size and there is no overlap between groups. It follows the system: domain, kingdom, phylum, class, order, family, genus, species.
Explain the relationship between classification and evolution
Phylogenetic classification is based on characteristics which have the same evolutionary origins. Taxa are based on evolutionary line of descent. The highest taxonomic group is the domain which comprises Bacteria, Archae and Eukarya.
Describe the meaning of species diversity
The number of species and the number of individuals of each species within a community
Explain how a diversity index can be used
Species diversity index is a quantitative method of measuring species diversity. It takes into account both measures of species diversity, and enables a comparison to be made between different sites or the same site at different times. This can be useful in assessing the success of habitat management techniques.
Describe the effect of agriculture on species diversity and the species diversity index
Selective breeding leads to reduced allele frequency, so reduced genetic diversity. Creation of monocultures and the use of pesticides to reduce competition between pest species and the crop species reduce the species diversity index in an area.
Describe specific agricultural activities which reduce species diveristy, include direct and indirect examples.
Removal of hedgerows and grubbing out of woodland, filling in ponds and draining wetlands, over grazing, use of pesticides and inorganic fertilisers, espace of effluent from silage stores and slurry tanks in to water courses, absence of crop rotation and lack of intercropping or undersowing.
Explain how a balance between conservation and farming can be achieved
Maintain existing hedgerows or plant new ones, maintain ponds and wetland or create new areas. Reduce pesticide use, use biological control measures instead, use organic fertilisers, use crop rotations using nitrogen fixing plants, use intercropping to control weeds and pests, create meadows, don’t cut road vergs until after seed dispersal, introduce conservation headlands to encourage breeding of insects and wild flowers.
Explain the use of the following techniques in comparing genetic diversity within, and between, species:- Observable characteristics
This is an historic method of comparing genetic diversity and is based on the assumption that observable characteristics are coded for by genes. Variation within the characteristics corresponds to the number of and variety of alleles. This is unreliable due to polygenic characteristics, and environmental factors affecting observable characteristics.
Base sequence of DNA
Nucleotide bases can be tagged by dyes. This enables comparison of base sequences between organisms by computers. This can also be used to determine evolutionary relationships.
Base sequence of mRNA
As mRNA bases are complementary to DNA, sequencing mRNA can give the same information as that of DNA
Amino acid sequence of proteins
Since amino acid sequences are determined by mRNA which is determined by DNA, it can give a measure of genetic diversity. Amino acid sequences for proteins in different organisms can be compared. More similarities means closer evolutionary relationships.
Explain how immunological comparisons are used to investigate variations in proteins
Antibodies of one species will respond to specific antigens on proteins in the blood serum of another species. Serum from species A is injected into species B. Species B produces antibodies specific to the antigen sites on protein from species A. Serum is extracted from species Band mixed with the blood of species C. The antibodies respond to the corresponding antigens on the protein of species C. This forms a precipitate. Mre similar antigens leads to more precipitate being produced, and therefore indicates the two species (B & C) are closely related.
