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Patterns of evolutio
as part of AS91605 NCEA L3 Biology
| Term | Definition |
|---|---|
| adaptive radiation | Relatively sudden appearance of many new species from single ancestral type to fill a variety of niches. |
| analogous structures | Structures which are used for the same purpose, but which have a different structure and origin; e.g. wings of insects and birds (contrast: homologous structures). |
| co-evolution | When two species influence each other’s evolution. A change in one species acts as a strong selection pressure for change in the other species. |
| common ancestor | Original species from which others develop through divergent evolution |
| convergent evolution | Occurs when similar features evolve in unrelated species as a result of similar selection pressures e.g. streamlined body shape in dolphins and fish |
| divergent evolution | When one species evolves into two. |
| fossil record | all fossils and their relative locations in layers of rock. Provides evidence for timing, pattern and rate of evolution. |
| fossils | Preserved remains or traces of organisms which lived in the past. |
| gradualism | When the accumulation of changes resulting in speciation occurs slowly and steadily (contrast: punctuated equilibrium). |
| homologous structures | Structures which have the same origin, but different functions (contrast: analogous structures). |
| molecular biology | The branch of biology that involves or applies the study of DNA, RNA and proteins. |
| punctuated equilibrium | When there are long periods of little change (stasis) in a species, followed by short bursts of rapid speciation. |
| stasis | A period of little or no evolutionary change in a species |
| vestigial organ | An organ that was once useful in an animal’s evolutionary past, but now has no apparent function e.g. wings on many flightless birds. |
| Comparative anatomy | Homologous traits show relatedness and analogous structure convergence. |
| Hox Genes: | highly conserved group of genes involved in determining the basic structure and orientation of an organism. Because highly conserved (little change over evolutionary time), suggests shared ancestry. |
| mutations as evidence | the more shared mutations the more closely related two species are. |
| Mitochondrial DNA (mtDNA) | passed on maternally. The rate of gene mutation in mtDNA is steady as the only source of mutation can be used as a molecular clock. |
| Biogeography as evidence | Biogeography provides evidence for evolution by demonstrating that the geographic distribution of species. e.g., Present day distributions can be linked to the break up of Gondwanaland and therefore shared ancestry. |
| clade | A clade is a group of organisms that includes a common ancestor and all of its descendants. |
| nDNA | DNA found in the nucleus of a cell, inherited from both parents, and containing most of an organism’s genetic information. |
| Niche | includes an organisms habitat, its role (job) and the adaptations to survival and reproduce successfully. |
| Vicariance (physical mechanism for allopatric speciation) | where species are separated and evolve independently due to geographical barriers: The population stays still, and the landscape changes around it (passive). |
| Dispersal (2nd physical mechanism for allopatric speciation) | where species are separated and evolve independently due to moving to another area: A few members of a species move across a pre-existing barrier, such as finches flying to the Galápagos Islands (active). |
Created by:
NZARoberts