Evolution

Evolution Change over time Gradual Large groups (not individuals)

Theory Well – supported TESTABLE explanation Not just an “I have a

theory” Idea/Opinion not

Theory!!! Theories can change Theories can be false

Charles Darwin Born in England Set Sail and traveled

(H.M.S. Beagle 1831) Recorded MANY

observations Which became evidence To support how life

changes over time. WROTE everything down! ANALYZED everything!

Charles Darwin He noticed how plants and animals seem to

be adapted to their environments. AND how some environments, even though

identical, had many different plants and/or animals.

Charles Darwin Didn’t only look at LIVE plants and animals Fossils

Preserved remains of ancient animals.

Movie http://video.nationalgeographic.com/video/pla

yer/places/parks-and-nature-places/coasts-and-islands/ecuador_galapagos.html

Galapagos Islands Land Tortoises (GIANT) Marine Iguanas (land too) Birds (Darwin’s Finches)

Belief of the Time Was believed during Darwin’s time, that the

Earth had only been formed a few thousand years before

AND That NOTHING had ever changed!

James Hutton and Charles Lyell First to say that Earth is many millions years

old. 1795 – Geological Theory (Hutton)

Change on the Earth happens slowly Rain, Heat, Cold bury or push up the Earth

1830 – Lyell wrote Principles of Geology Scientists must explain past events by processes

that can be OBSERVED. Because what happened then, happens now.

Principals of Geology Darwin read this book while on the H.M.S.

Beagle Remember: Written by Charles Lyell

He saw rocks raised from the sea floor (that had muscles on them) that were now mountains

He concluded the same ideas (Lyell had) would effect/change life too (not just rocks/land).

Lamarck’s Theory of Evolution Jean-Baptiste Lamarck – French Naturalist 1809 Published his theory (Year Darwin was

born) States:

Organisms adapt to their environment Use a feature – keep it Don’t use a feature – lose it. Everything evolves towards perfection and

complexity. Inheritance Did not know that behavior does NOT influence

inherited characteristics.

Bird Wings (Ostrich/Falcon)

Lamarck’s Theory of Evolution

But… Lamarck believed that everything evolved toward perfection and that just by needing something to survive, it would appear.

Thomas Malthus 1798 – Theory of Population Growth

If Human populations grow unchecked, we would run out of room (living space) and food.

What keeps us in check? War (Violence), Famine (lack of food), Disease Basically – Death!

Charles Darwin Realized that Malthus’ Theory of Population

Growth applies to plants and Animals even more strongly. Maple Trees – 1,000’s of seeds in one summer Oysters – 1,000,000’s of eggs each year Yet we are not over-run by oysters or maple trees MORE die than survive.

H.M.S. Beagle Darwin sailed from 1831-1836 What did he return with?

Specimens Plants AND Animals

Notes/Observations Books of Data

5 Years of Data!

Darwin’s Ideas Were RADICAL for their time

So radical, he was afraid of what would happen if he went public

So he only discussed them with his friends. His manuscripts were published AFTER he

died. AND he knew there were some things he

could not explain. He wrote that if the missing links weren’t found, to

disregard much of his work Because he made some HUGE ASSUMPTIONS.

Alfred Russel Wallace Naturalist Who in 1858 summed up much of Darwin’s

thoughts from the previous 25 years They did not know each other! What do you think that did for Darwin?

Gave him the incentive and the initiative to publish his own work. SOME of it at least.

On the Origin of Species Includes information on Natural Selection

Process of evolution Over millions of years And continues now

Remember: Evolution is change over TIME.

Natural Variation Differences among species WE are all different Fruit, milk, production, size All inherited!

Selective Breeding Farmers and breeders pick the BEST to breed

for the qualities they want. Produce the BEST crops, the BEST animals

This is known as Artificial Selection Not “natural” mating patterns – humans CHOOSE.

Natural Selection In Nature – the struggle to exist Malthus’ work on population growth fits into

this. Is there enough food, space, necessities, traits

Examples: Speed (are you fast enough to avoid being eaten?) Visibility (can you be seen?)

Survival of the Fittest Fitness

Is the ability to live and reproduce Need to ADAPT

Need to change Adaptations are evolution!!!

Better Suited to live in their environment Example: Marine Iguanas

If you don’t adapt/change then you die You die, then you produce no offspring (or just a few before

you die)

Keys to Evolution! Natural Selection

Survival of the Fittest

Generations compete to Survive and Thrive (have offspring)

OVER TIME: Natural selection CHANGES organisms – they

evolve – This is called Decent with Modification

This IMPLIES that ALL organisms are related to one another – They have Common Descent.

Excerpt from the book (Page 382) “ Descent with modification also implies

something else: that all living organisms are related to one another. Look back in time, and you will find common ancestors shared by tigers, panthers, and cheetahs. Look farther back, and you will find ancestors that these felines share with horses, dogs, bats and primates. Father back still are the common ancestors of mammals, birds, alligators, and fishes. If we look far enough back, the logic concludes, we could find the common ancestors of all living things. This is the principle known as common descent. According to this principle, all species – living and extinct – were derived from common ancestors.”

Excerpt from the book continued (Page 382) “Carry the concepts of descent with

modification and common descent to their logical conclusion, and what do they produce? A single ‘tree of life’ that links all livings things on Earth. Darwin conceived this idea long before he published his theory of evolution.”

THIS is the controversy! This is a HUGE jump – there are missing links

and assumptions that still have not been answered.

Is there evidence of evolution all around us? Yes!

Does that mean we came from apes? You decide!

What does the Fossil Record show? (Ancient remains that are preserved.) Shows similarities in animals Some look the same, some do not – but

STRUCTURES are similar Homologous Structures Vestigial Organs

37 day old fetus

Humans Have Tails!

Homologous Structures Different mature forms, but develop from the

same embryonic tissues

Vistigial Organs Structures that don’t develop into mature

forms

Summary of Darwin’s Theory (Page 386)