QCAA Biology - Glossary defintions

carrying capacity

in Biology, the size of the population that can be supported indefinitely on the available resources and services of that ecosystem

clade

a group of organisms that consists of a common ancestor and all its lineal descendants

ecological niche

the role and space that an organism fills in an ecosystem, including all its interactions with the biotic and abiotic factors of its environment

evolution

change in the genetic composition of a population during successive generations, which may result in the development of new species

Gene

region/s of DNA that are made up of nucleotides; the molecular unit of heredity

Genome

all the genetic material in the chromosomes of an organism, including its genes and DNA sequences

keystone species

a plant or animal that plays a unique and crucial role in the way an ecosystem functions

Macroevolution

the variation of allele frequencies at or above the level of species over geological time, resulting in the divergence of taxonomic groups, in which the descendant is in a different taxonomic group to the ancestor

Microevolution

small-scale variation of allele frequencies within a species or population, in which the descendant is of the same taxonomic group as the ancestor

polygenic inheritance

when one characteristic is controlled by two or more genes

interspecific hybrids

Examples include: mule, liger and zorse

Features of pioneer species

nitrogen fixing, tolerant to extremes, fast growing, photosynthetic, high reproductive rate

Recombinant DNA process

1. Isolation of target gene
2. Cutting of target gene and plasmid (restriction enzyme)
3. Joining of target gene with plasmid
4. Amplification of recombinant DNA plasmid

Nucleotide

Nitrogenous base, Deoxyribose sugar, phosphate

Assumptions of cladisitics

Common ancestry (LUCA), Bifurcation, physical change over time