biology journal 1/25/2010

Biology Journal 1/25/2010

Think about a salmon and an Think about a salmon and an elephant. What would some elephant. What would some derived traits for the fish and the derived traits for the fish and the elephant? What conserved traits elephant? What conserved traits do they have?do they have?

What are the 4 steps of What are the 4 steps of natural selection? What natural selection? What happens in each step?happens in each step?

Biology Journal 1/18/2013

What is What is environ-environ-mental mental pressure?pressure?

What could What could be some be some examples examples of it?of it?

What can happen if environmental pressure gets too great?

EvolutionWhy are there so Why are there so

many different kinds many different kinds of things?of things?

Alfred Russel Wallace

(1823-1913)

Charles Darwin

(1809-1882)

Alfred Wallace and

Charles Darwin:

designers of the

theories of Natural

Selection and

Evolution

These scientists observed slight These scientists observed slight differences in animals and differences in animals and

wondered: wondered: what’s the deal?what’s the deal?

Stops on Darwin’s Stops on Darwin’s Evolution Evolution RevolutionRevolution World Tour 1831-1836 World Tour 1831-1836

The Galapagos Islands: a group of islands The Galapagos Islands: a group of islands named after some Spanish stuff.named after some Spanish stuff.

Darwin noticed subtle differences Darwin noticed subtle differences between the Finches on the between the Finches on the Galapagos IslandsGalapagos Islands

Why do so many different Why do so many different kinds of Finches exist???kinds of Finches exist???

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

What up, cuz?What up, cuz?

Great moments in evolution

What is evolution?Evolution is the development of new

types of organisms from preexisting types.

• It takes place because of changes in the genes in a population, over time.

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.

What did we artificially select these dogs to do?

Pit Bull

Siberian HuskyGreyhound

Bloodhound

GoldenRetriever

St. Bernard FoxhoundGerman

Shepherd

What are some other animals What are some other animals we’ve artificially selected?we’ve artificially selected?

Black Angus Holstein Texas longhorn

Draft Horses Thoroughbreds Ponies

Artificial selection is how all of our crops and food animals have become big, resistant to the environment, delicious and nutritious!

Sometimes too big

Doing this to Doing this to humans is humans is called called “eugenics” “eugenics” and is usually and is usually just an excuse just an excuse for a racist for a racist agenda. agenda.

Jessie Owens, a Jessie Owens, a black US track black US track and field athlete, and field athlete, defeated the defeated the Germans, winning Germans, winning 4 gold medals in 4 gold medals in the 1936 the 1936 Olympics held in Olympics held in Berlin, Germany.Berlin, Germany.

Who’s the inferior race Who’s the inferior race now?now?

Another great moment in evolution

Biology Journal 1/26/2010

Compare and contrast natural selection and artificial selection in a Venn diagram.

Evolution is a theory• Evolution is

supported by evidence and experiment.

• Natural selection, however, is undeniable, because we can see it happen.

So here’s the evidence…

Fossils

The truth is under there.

1. Fossil Record

As the rocks get older, we can track what kinds of organisms were alive at different time periods over all of earth’s history.

Homologous structuresOrgans that do different things, but all have the same structures.

These animals all must be related to a single species in the past.

Homologous structuresOrgans that do different things, but all have the same structures.

Homologous structuresOrgans that do different things, but all have the same structures.

Analogous Structures do the same thing, but are not related by evolution, and therefore have different structures.

Vestigial Structures• Vestigial organs are ones that are

present but have no purpose.

Why are they there?

Vestigial Structures in Humans

• Appendix: Attached to your small intestine. Does nothing. Then it gets infected and kills you.

Vestigial Structures in Humans

• Coccyx: it used to be individual bones of a tail. Now is one fused mass.

Vestigial Structures in Whales

Similarities in DNA shows how closely related two species are.

Humans and chimps have 98.8% the same DNA

Humans have up to 33% the same DNA as some single-celled organisms.

Embryonic Similarities

As many animals grow up in the uterus, they all share the same development and structures.

Why would they do that???

Embryonic Similarities

A dolphin with hind-leg flippers

• 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…

An “extra” arm on an 11 year old boy.

• Mutations help move along evolution by creating diversity. Some traits will be good. Some will be bad…

Evolution: Change that MattersEvolution: Change that Matters