6-2/3 Notes – Biological Evidence & Plate Tectonics Chapter 6 Lessons 2 & 3

Continental Drift Acceptance of the continental drift hypothesis led to the development of the theory of plate tectonics.

Continental Drift As lithospheric plates move, they create environmental changes for the organisms that live in or near them.

Continental Drift The changes lead to the development of and extinction of species.

Continental Drift Australia has a large population of mammals belonging to the group called marsupials. Few species of marsupials exist on other continents.

Geographic Isolation Geographic isolation occurs when populations of species are separated by a physical barrier.

Geographic Isolation Once separated, the populations might follow different evolutionary paths.

Geographic Isolation The results of geographic isolation prompted much of Darwin’s research.

Geographic Isolation Species on an island were more similar to those on the mainland even though the two environments were different.

Geographic Isolation These observations led to the idea of evolution by natural selection.

Geographic Isolation vs. Convergent Evolution Sometimes distant locations with similar environmental conditions have species with similar traits (analogous structures). The species developed independently but under similar conditions.

Geographic Isolation vs. Convergent Evolution Octopuses and humans both have eyes - does that mean they share a recent common ancestor?

Geographic Isolation vs. Convergent Evolution No. Convergent evolution - when two separate groups of animals evolve to have similar structures independently of one another. wings of bats and birds prickly bits of porcupines and hedgehogs

Geographic Isolation vs. Convergent Evolution Convergent evolution results in structural and functional similarities. Examples include placental mammals in the Americas and marsupials in Australia.

What term describes the separation of populations by physical barriers? Acontinental drift Bgeographic isolation Cconvergent evolution Dtheory of plate tectonics 6.3 Evolution and Plate Tectonics

What did Darwin observe about geographically isolated populations? ASpecies on distant islands with similar environmental conditions were similar. BSpecies on islands and the mainland had undergone convergent evolution. CSpecies on islands were similar to those on the mainland even though the environments were different. DSpecies on the islands were more similar to each other than species on one island and the mainland. 6.3 Evolution and Plate Tectonics

What is the term for how very distantly related species can appear similar? Ageographic isolation Brecent common ancestry Cconvergent evolution Dnatural selection 6.3 Evolution and Plate Tectonics

What does NOT explain the gaps in the fossil record? AMost organisms decay before fossilization. BFossils are unreliable for studying Earth’s history. CSome fossils have not been found yet. DGeological processes destroy fossils.

Most organisms decay before fossilization. Some fossils have not been found yet. Geological processes destroy fossils. These are the reasons WHY.

Analogous structures are an indication of ____. Aconvergent evolution Ba common ancestor Ccontinental drift Dgeographic isolation

What does the fossil record NOT indicate? ASpecies have evolved through natural selection. BMost species that lived on Earth are extinct. CEnvironmental conditions on Earth have not changed much. DIn Earth’s early history, life was less complex.

How does the movement of lithospheric plates possibly lead to the evolution of a new species? Aconvergent evolution Bhomologous structures Cenvironmental changes Dcontinental drift SCI 4.f