Diversity and Adaptation Flashcards
Genetic Diversity-1
The greater the number of different alleles that all members of a species possess, the greater the genetic diversity of that species.
Allele frequency
the number of times an allele occurs within the gene pool in a population, relative to all others at same locus
all the different alleles of all the genes of all the individuals in a population at any one time
Gene pool
Natural Selection
Natural Selection is Darwin’s theory to explain the mechanism of evolution. The process by which organisms better adapted to their environment survive and reproduce and pass on their advantageous alleles to the their offspring, whilst those less well adapted fail to do so.
Directional selection
Favours one extreme of the range of characteristics and the other extreme is selected against – shift in population curve
Favours the mean of the distribution because the extremes are at a selective disadvantage – frequency of mean phenotype increases
Stabilising selection
Group of genes that are responsible for controlling a characteristic.
Polygenes
A bell-shaped curve produced when a certain distribution is plotted on a graph
Normal distribution curve
Biodiversity
The range and variety of genes, species and habitats within a particular region. Made up of three components: genetic diversity, species diversity and ecosystem diversity.
A group of organisms that have a common ancestry and so share the same genes and are capable of breeding together to produce fertile offspring - are reproductively separated from other species.
Species
Linnaeus’ system to name species. 1st: Generic name (genus). 2nd: Specific name (species) E.g. Felix tigris
Binomial naming system
Groups within larger groups; with no overlap between groups at each rank
Hierarchy
Process of classifying organisms based on differences useful at time e.g. colour, size, number of legs
Artificial Classification
Phylogenetic Classification
Process of classifying organisms based upon evolutionary relationships between organisms and ancestors
Characteristics with the same function not the same evolutionary origins. e.g. wings of butterflies and birds used for flight but originated in different ways.
Analogous Characteristics
Homologous Characteristics
Characteristics with similar evolutionary origins regardless of their functions in the adult of a species e.g. wing of a bird, arm of a human and front leg of a horse
Taxon
Each group within a phylogenetic biological classification (pl. taxa)