Biology Journal 1/25/2010. Think about a salmon and an elephant. What would some derived traits for the fish and the elephant? What conserved traits do they have?. Biology Journal 1/18/2013. What are the 4 steps of natural selection? What happens in each step?.
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Think about a salmon and an elephant. What would some derived traits for the fish and the elephant? What conserved traits do they have?
What are the 4 steps of natural selection? What happens in each step?
What could be some examples of it?
Why are there so many different kinds of things?
Alfred Wallace and Charles Darwin: designers of the theories of Natural Selection and Evolution
Alfred Russel Wallace
These scientists observed slight differences in animals and wondered: what’s the deal?
The Galapagos Islands: a group of islands named after some Spanish stuff.
Darwin noticed subtle differences between the Finches on the Galapagos Islands
Environmental pressure shaped the finches on the Galapagos Islands to be good at getting a specific food.
The more quickly you can reproduce and go through a generation, the more quickly you can evolve.
Bacteria evolve in days; fruit flies evolve in months; polar bears evolve in millions of years.
For most organisms, evolution takes a long time. They’re just changing due to natural selection.
and that’s how this kind of stuff happens
Populations (not individuals!) change based on what’s an advantage
Evolution is the development of new types of organisms from preexisting types.
Humans can try to influence natural selection and evolution by controlling who reproduces and with whom. This is called artificial selection.
Through thousands of years of artificial selection, humans turned wolfs, majestic symbols of nature and independence, into helpless, dumb poodles.
Sometimes too big
Jessie Owens, a black US track and field athlete, defeated the Germans, winning 4 gold medals in the 1936 Olympics held in Berlin, Germany.
Who’s the inferior race now?
Compare and contrast natural selection and artificial selection in a Venn diagram.
So here’s the evidence…
The truth is under there.
As the rocks get older, we can track what kinds of organisms were alive at different time periods over all of earth’s history.
Organs that do different things, but all have the same structures.
These animals all must be related to a single species in the past.
Why are they there?
Humans have up to 33% the same DNA as some single-celled organisms.
Humans and chimps have 98.8% the same DNA
As many animals grow up in the uterus, they all share the same development and structures.
Why would they do that???
And every once in a while, genetic mutations happen that allow us to understand how new structures could form. But they’re not always an advantage…
A dolphin with hind-leg flippers
Mutations help move along evolution by creating diversity. Some traits will be good. Some will be bad…