Period 2 Biogeography

According to Charles Darwin "closely allied" species are creatures that share roughly the same body plan. He wrote "such closely allied species tend to be found on the same continent or within the same group of oceanic islands." Darwin wondered "why should 'closely allied' species inhabit neighboring patches of habitat? And why should similar habitat on different continents be occupied by species that aren't so closely allied?"
Darwin wrote "This bond, on my theory, is simply inheritance." Similar species occur nearby in space because they have descended from common ancestors.

Closely allied species are usually found on the same continent (such as the different species of Zebra in Africa), or in the same cluster of islands in the oceans— despite the different habitats, food sources, and conditions of climate. Some examples of these closely allied species are the flightless birds found in S. America, hares and rabbits in terrestrial habitats or beavers and mukrats in the wetlands.

Island Biogeography: Species from the source area disperse to an island at a rate that depends on the distance of the island from the source area. The fewer species there are on the island, the more immigration will take place. The more species on the island, the less immigration will occur because species will have already reached the island. There is also a rate at which species go extinct on the island. The more species there are on the island, the higher the extinction rate. (

Palentology reveals a similar clustering patern in the dimension of time such as what Dariwn stated with physical boundries such as oceans and rivers. "Although a particular type of habitat may occur throughought the world, seices in one hbitat are more closely related to nerby speices in their own habitats than to specices in the same habitat elsewhere"( What Darwin had noticed about this recored was that the closely allied spiecies tend to found adjacent to one another not only in physical limitations but time as well. An example of this is the horselike creature known as the "Hyracoterium" wich was successeeded by the "Orohippus" then the "Mesohipps"… wich then became horseish animals.
Darwin argued that closley allied species succed one another in time, as well as living in space, because they're related through evolutionary descent.
Embrology, according to [ ] means "the branch of biology that studies the formation and early development of living organisms" According to Darwin it too involved pattersn that could not be explained by coincidence. He wrote, "the embryo is the animal in its less modified state: and that state "reveals the structure of its progenitor." Embryology research continues to rapidly expand in several different directions all at once (stem cells, genetic, molecular, biomechanical mechanisms, teratology and new animal models).[ ]

The Mouse Genome effort accumulated 30,000 genes, 99% having counterparts in humans

Over-use of pesticides and antibiotics causes resistant strains to appear more rapidly than those that are not being exposed to the antibiotics or pesticides.

According to [] Biogeography is the study of the distributions of plants and animals over the surface of the Earth in both space and time. The spatial component of biogeography attempts to describe and explain the distributions of one or more species over the world.

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