evolution the process of change over time. theories of how we came to be… evolution is a...

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Evolution The process of change over time.

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Evolution

The process of change over time.

Theories of how we came to be…

Evolution is a scientific theory.

Other Theories…?

Evidence: geologic record

Oldest fossils in layers.lowest

Organisms evolved from to One cell multicellular

A real FOSSIL!A real FOSSIL! Remains of any organismRemains of any organism

Okay, they are supposed to be the remains of DEAD things!

Fossils can be:

1. Frozen organisms.

2. Organisms petrified in stone.

3. Traces of organisms petrified in stone.

4. Organisms preserved in sap or tar.

Microorganisms fossils

Worm fossil

Mollusk fossil

Insect fossil

Fish fossil

Reptile fossil

Bird fossil

FOSSILS for real!

Hot (or Not-S0-Hot) Shots of Evolution

• Developed the theory of “Use and Disuse”

• Basically, whatever changes occur over your life time, you pass along to your kids!

• WRONG!!Jean Lamarck

Karl Weismann

• Disproved Lamarck

• Cut off mouse tails for several generations

• Each generation of mice were still born with full tails!

Charles Darwin: Charles Darwin: THE Grandpappy of THE Grandpappy of

Evolution!Evolution!

• Medical Medical school-school-passed passed out at autopsyout at autopsy

• Law schoolLaw school-too -too boring!boring!

• MonkMonk-more -more boring!boring!

• NaturalistNaturalist--yahoo!yahoo!

Voyage of the HMS Beagle:

Darwin visited many parts of the world over 5 years.

He was most interested in the Galapagos Islands off of Ecuador… WHY?

•Many small islands

•All had different climates

•Had many organisms that were similar, but slightly different, and perfectly adapted to their environments!!

Darwin’s Ship

Galapagos TortoisesThere are 14 different species of tortoise on the Galapagos islands…They all came from a common ancestor millions of years ago.

On wet islands, the shells are rounder and more helmet-shaped. These tortoises can feed off the ground and maintain better protection.

On dryer Islands, Tortoises have saddle-shaped shells which allow them to get their heads high up in the vegetation to feed.

Natural Selection:Darwin’s Theory of Evolution

In a nutshell, “Nature” determines which organisms live and which die.

Natural Selection: Overproduction

An oyster lays eggs at a time!

60million

Natural Selection:Darwin’s Theory of Evolution

In a nutshell, “Nature” determines which organisms live and which die.

1. Overproduction: This guarantees some will survive.

Natural Selection: Variations

Variations can come about in two ways:

1. Sexual Reproduction creates a new and unique combination of genes.

You did NOT just talk about S-E-X,

right?

2. Mutations (a change in your DNA) occurring in the gametes (sex cells, ex: egg and sperm).

OMG, you did it again.

Natural Selection:Darwin’s Theory of Evolution

In a nutshell, “Nature” determines which organisms live and which die.

1. Overproduction: This guarantees some will surivive.

2. Variation Among Offspring: The more diversity, the stronger a species.

Natural Selection: Competition

Organisms Compete For:• Food

• Water

• Shelter

• Mates

• Territory

Natural Selection:Darwin’s Theory of Evolution

In a nutshell, “Nature” determines which organisms live and which die.

1. Overproduction: This guarantees some will surivive.

2. Variation Among Offspring: The more diversity, the stronger a species.

3. Competition: Fighting for food, water, mates, territory and shelter. The best adapted get the best digs!

Natural Selection: Survival of the Fittest

Which of these hotties is the

most fit?Depends…if their “environment” is a 4’ tall spaceship with tight quarters…the little puny alien is the most fit!

video

But, What if the Environment Changes?

Which moth lives longer here?

What about now? After pollution has covered the forest in soot and smog?

Natural Selection:Darwin’s Theory of Evolution

In a nutshell, “Nature” determines which organisms live and which die.

1. Overproduction: This guarantees some will surivive.

2. Variation Among Offspring: The more diversity, the stronger a species.

3. Competition: Fighting for food, water, mates, territory and shelter. The best adapted get the best digs!

4. Survival of the Fittest: This does NOT mean big and strong, it means best adapted to the environment survive and reproduce.

Question:

Populations ADAPT,

Individuals have ADAPTATIONS

Remember,

Individual with a black color adaptation

Individual with a white color adaptation

How relationships are determined

Scientists use several types of evidence to determine relationships.1.

2.

3.

4.

Com

para

tive E

mbry

olo

gy

fish

salaman-der

tor-toise

chic-ken pig cow rabbi

thumanfish

How relationships are determined

Scientists use several types of evidence to determine relationships.1. Comparative Embryology

2.

3.

4.

Which pair of organisms is more Which pair of organisms is more closely closely

related biochemically?related biochemically?

Vs.

Vs.

Which of these are related??

How relationships are determined

Scientists use several types of evidence to determine relationships.1. Comparative Embryology

2. Comparative BioChemistry

3.

4.

Comparative… Anatomy

Not to be confused… (alas, my specialty!)

Homologous Structures:

Similar structures that have been inherited from a common ancestor, regardless of use (swim, fly, etc.)Analogous Structures:

Serve a similar purpose (ex. Flying) but evolved independently from one another.

How relationships are determined

Scientists use several types of evidence to determine relationships.1. Comparative Embryology

2. Comparative BioChemistry

3. Comparative Anatomy

4.

Remember Cells?

Prokaryote Eukaryote

And…There are TWO kinds of Eukaryotic

Cells…

OR

Plant Cells Animal Cells

How relationships are determined

Scientists use several types of evidence to determine relationships.1. Comparative Embryology

2. Comparative BioChemistry

3. Comparative Anatomy

4. Comparative Cytology

Causes of Evolution

Sexual reproduction& variations

Spontaneous & random mutations

Environmental Changes

Beneficial mutations depend on the

__________!environment

Two Schools of Thought…

Gradualism is the idea that changes took place slowly over time.

Punctuated Equillibrium is the idea that there were long periods of stability and short bursts of change when the environment changed.Punctuated Equillibrium is a more widely

accepted theory.

Evolution Explained…Evolution Explained…(In case I didn’t already do that!)(In case I didn’t already do that!)

Most life actually evolved recently, Most life actually evolved recently, in evolutionary terms!in evolutionary terms!

LINK

A bit more detail…A bit more detail…

LINK

The final Story