evidence what evidence do we have to support the idea of evolution by natural selection?
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WHAT EVIDENCEEVIDENCE DO WE HAVE TO SUPPORT THE IDEA OF EVOLUTION BY NATURAL SELECTION?
FOSSILSFOSSILS any remains of life from
an earlier time and the most abundant evidence for evolution
Sedimentary rock contains the most fossils and is formed from mud, sand, and other fine particles
How do scientists figure out how old something is?
Relative Dating —looking at where the rock is located. Older layers are deeper than the layers above. This method only provides an estimated age of a fossil.
How do scientists figure out how old How do scientists figure out how old something is?something is?
Radioactive Dating —measuring how a radioactive element in the fossil (like Carbon or Uranium) has decayed. They compare the amount of stable rock to amount of radioactive element still present.
Not the same kind of dating… Not the same kind of dating…
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html
Fossils document how organisms changed over time, but much of the fossil record is missing or incomplete (like a book with pages ripped out)!
Fossil Hunting on the Galapagos
THERE ARE DIFFERENT KINDS OF FOSSILS…AND DIFFERENT WAYS THAT FOSSILS CAN FORM…
Amber Fossils
Prehistoric termites trapped in amber
Lizard in Amber
Frog in Amber
Fossils that are hardened in tree sap…
Woolly Mammoths
Bones…
Frozen in ice or permafrost…
When do humans “show up” on the planet?
Fossils by Brainpop
Fossils Adv. by Brainpop
Geologic Time by Brainpop
Additional Video ClipsAdditional Video Clips
HOMOLOGOUS STRUCTURESHOMOLOGOUS STRUCTURES
body parts that are similar in origin and structure.
Example: arms, dolphin fin, bat wing, bird wing
VESTIGIAL STRUCTURESVESTIGIAL STRUCTURES
A body part that is reduced in size and does not seem to have a function.
Examples: human appendix,
wisdom teeth and muscles that are for moving the ears.
EMBRYOLOGYEMBRYOLOGY study of the development of
embryos (an organism in its earliest stages of development).
ExamplesExamples: gills and tailbones in humans
What similarities do you see between these embryos?
COMPARING DNA CODESCOMPARING DNA CODES the closer the DNA sequences are in
organisms, the more closely related they are.
Example: DNA has shown that dogs are the closest relatives of bears. Human’s closest relatives are from the ape family.
Cousins?
Example: Humans are most closely related (99.9%) to chimpanzeeschimpanzees.
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html
Other Video Clips
Elephant Evolution
Woolly Mammoths
WHAT CONCLUSIONS CAN BE DRAWN FROM THESE CONCEPTS?
DIVERSITYDIVERSITY over millions of years, the
process of natural selection has created all the different life forms on Earth. Scientists estimate anywhere from 5 million to 100 million species on the planet, but have only identified about 2 million.
DIVERSITYDIVERSITY
CLICK HERE FOR A BIODIVERSITY INTERACTIVE MAP:http://www.biodiversityhotspots.org/xp/Hotspots/pages/map.aspx
RELATEDNESSRELATEDNESS since species evolve from one to the
other, there is always a degree of similarity between them. Generally, the more closely related they are, the more recently they evolved or separated into distinct species. All species are connected on earth because they all share some level of DNA.
RELATEDNESSRELATEDNESS
RELATEDNESSRELATEDNESS
TREE OF LIFE WEB PROJECT: http://tolweb.org/tree/
EXTINCTIONEXTINCTION occurs when an entire species dies
out Due to a change in the
environment without time to adapt/evolve to survive in it
EXTINCTION BY BRAINPOPEXTINCTION BY BRAINPOP