BIOA01H3 Lecture Notes - Lecture 4: Convergent Evolution, Parallel Evolution, Adaptive Radiation

• School: UTSC
• Department: Biological Sciences
• Course: BIOA01H3
• Professor: Maydianne Andrade

Document Summary

Lineages should change over time and sometimes diverge (speciate: there should be gradual changes in species" morphology through fossil record. Trilobites and the number of ribs in the tail region vary. Changes in body size of horse species over time: one lineage will sometimes divide into two or more in the fossil record. Ectoprocts: there should be links between patterns of change and species" distribution. Two types of distribution: vicariance: when biotic or abiotic barriers arise to divide a species into two so that they cannot interbreed and therefore become distinct species. Historical vicariance events: split-up of pangaea then laurasia and gondwana, formation of the rocky mountains. Current vicariance events: habitat fragmentation, dispersal: movement of individuals or groups to new habitats/regions. Major historical dispersals: e. g. formation of land bridges allow movement of taxa, asia & north america (bering land bridge, 13,000 to 10,000 ya, north & south america (isthmus of panama, 3 mya.