Period 8 Biogeography

1. Darwin thought there was a reason for "allied species" being on different continents. They were usually on the same continent but something caused them to show up on different ones. On South America there are the rheas, large flightless birds that are similar to those of Africa, the ostrich, and Australia, the emus. This example was the result of inheritance.

2. Paleontology reveals links between past and present organisms. Less ancient fossils lay on top of more ancient fossils. In the article it says that Darwin found that allied species tend to be "found adjacent to one another in successive strata." After a species "endures" many years, before it totally dies off another species that are similar replaces it. Like how the Hyracotherium was succeded by Orohippus then Ehihippus, then by Mesohippus, and etc..

3. The world is divided up into major biogeographical subdivisions. Those are Nearctic, Neotropical, Palearctic, Ethiopian, Oriental, Australian, and Oceanic. The Antarctic is sometimes also included "as a zone". The Nearctic and Palearctic are sometimes referred to together as the Holarctic. The area covered by Nearctica is considered Canada, the U.S., and Greenland.

4. Along with paleontology, embryology also involved patterns in organisms that could not be explained by coincidence. He talked about how they would not be coincidence because of how embryos of mammals resemble stages of a reptile during certain stages, larval forms of a barnacle before metamorphosis are similar to the larval form of a shrimp, and other reasons.

5. He concluded that they were not coincidence because "the embryo is tha animal in its less modified state", and that it "reveals structure of its progenitor."

6. A progenitor is "an ancestor in the direct line: FOREFATHER: a biologically ancestral form".
(Merriam-Webster Online).

7. Darwins quote "the embryo is the animal in its less modified state" and the state "reveals the structure of its progenitor." This response was to the question of - Why do the larvae of moths, flies, and beetles resemble one another more than any of them resemble their respected adults.

8. "Noted the wings of fof flaying fish. Althought the fish's wings are rudimentary compared to a bird's, he realized that they derived from the same evolutionary process: They enable the fish to soar to escape predators." This showed how birds could evolve similar traits but could be in different areas of the world.

9. "Even Today its on display in the layout and organization of any zoo." Darwin was talking about how animals could be broadly compared even if they were not related by habitat of species. Similar traits show his idea of Morphology.

10. What is Biogeography? "The study of the distribution of biodiversity over space and time. It aims to reveal where organisms live, at what abundance, and why." This is pretty much showing how organism grow and adapt and how they seem so similar but with great differences and may live on different sides of the planet.

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