1 / 20

Speciation

Explore how species evolve from preexisting species and the criteria for defining a species. Learn about different types of speciation and the theories of gradualism and punctuated equilibrium. Discover the patterns of macroevolution, such as divergent and convergent evolution, and the concepts of extinctions and coevolution. Watch a video explaining the fascinating process of speciation.

coppedge
Download Presentation

Speciation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Speciation How does a species evolve from preexisting species?

  2. What is a Species? • Group of organisms that look alike, can interbreed, & mate to produce fertile offspring in nature

  3. What do you get when you breed a donkey and a horse? A MULE!!! Does the mule fit the definition of a species?

  4. Why does a MULE NOT fit the definition of a species?? • Can interbreed XProduce fertile offspring • Do so in nature

  5. What do get when you breed a tiger and a lion? A LIGER!!! Does the liger fit the definition of a species?

  6. Why does a LIGER NOT fit the definition of a species?? • Can interbreed XProduce fertile offspring XDo so in nature

  7. Speciation = evolution of a new species • Happens b/c reproductive isolation • 3 ways

  8. 1. Behavioral Isolation • B/C different courtship rituals or other reproductive behaviors, like bird calls/songs • Ex. Eastern & Western Meadowlark

  9. 2. Geographical Isolation • When physical barriers (mountains, rivers, highways) separate populations • Ex: Grand Canyon squirrels, Darwin’s finches

  10. 3. Temporal Isolation • B/C pops reproduce @ different times • Ex. species of orchids & frogs

  11. Speciation can occur slowly or quickly 2 theories

  12. Gradualism • Species originate through a slow, steady change in adaptations • Proposed by Darwin • Supported by the fossil record

  13. Punctuated Equilibrium • Speciation occurs quickly in rapid bursts, with long periods of stability • Caused by environmental changes (ex. 3 isolations) • Supported by fossil record

  14. Species will diversify when introduced to a new environment or become extinct. 2 Patterns of Macroevolution

  15. 1. Divergent Evolution(adaptive radiation) • When species evolves into diverse new species • B/c different environments • Have homologous structures • Ex: polar vs. brown bear, Hawaiian honeycreeper

  16. 2. Convergent Evolution • Distantly related (or unrelated) organisms evolve similar traits • B/C similar environments • Have analogous structures

  17. Examples • Dolphin, penguin, fish - Streamlined shape b/c need to move thru water efficiently • Bird, bat, butterfly

  18. Extinctions: • 1. Background extinction - normal extinction rate, species that go extinct simply because not all life can be sustained on Earth and some species simply cannot survive. 2. Mass extinction  - widespread event that wipes out the majority (over 50%) of living plants and animals.

  19. Coevolution - the process by which two or more interacting species evolve together, each changing as a result of changes in the other or others • Beneficial relationships • ex. Acacia plant and stinging ant • Competitive relationships • Crabs and murex snails • Evolutionary arms race newt & snake 2:20-8:26min https://www.youtube.com/watch?v=iTjkSDaXF7s

More Related