Evolution: A theory that life changes over time

Charles Darwin

• His five year voyage on the HMS Beagle led him to eventually develop the theory of evolution

The three patterns of biodiversity:

• Species vary locally• Species vary globally • Species vary over time

Jean Baptiste LAMARCK

Sir Charles DARWIN

LAMARCK:

1. Acquired Characteristics2. Inheritance of Acquired

Characteristics

An example of Lamarck’s reasoning

• Question: How would Lamarck explain the evolution of the Giraffe?

• Find where Lamarck is using his two laws to falsely explain evolution in this case.

Artificial Selection

• Darwin’s use of artificial selection allowed him to recognize that variations were the raw material for evolution

Darwin’s Theory of Evolution

Charles DarwinNatural Selection

Struggle for Existence

Populations compete for food. Some

survive

Variation and Adaptation

Individuals have variations. Some are

better suited than others

Survival of the Fittest

Some are better adapted and will survive and have more off spring

*show brainpop: Darwin and then Natural selection

Natural Selection

• How is the “visual summary” on page 462 an example of natural selection?

What does Darwin’s theory suggest?......Common

Descent!

Evidence of Evolution : Biogeography – where organisms live now and where their ancestors lived in the past

• Closely Related but Different

• Distantly Related but Similar

Evidence for Evolution

• The age of earth and fossils of intermediate species

Evidence for Evolution:Comparative Anatomy

• Homologous structures

Evidence of Evolution:comparative anatomy

• Vestigial Organs

Evidence of Evolution:Comparative Anatomy

• Embryology

Genetics and Molecular Biology

Investigating Common Descent

Chapter 16 Assessment pg. 476 - 479

• Chapter 16.1 # 1-4• Chapter 16.2 # 8-13• Chapter 16.3 # 16-18• Chapter 16.4 # 25-29• Standardized Test Prep #1-11

Origin of Life

How Old is Earth?If 1 year is equal to a second…….• a half hour would take you back to 5 AD• 3 weeks would take you back to 100, 000 years (first human life)•20 years would take you back to the Cambrian age (500million years ago)

So, how did life begin?

Three Ideas

Creationism(faith based)

God created all living things

Spontaneous Generation

(observation)

Life arose from non-living matter

Ex. Dirt, water

Modern Scientific Theory(scientific method)

Life arose through chemical reactions

Spontaneous Generation

• all living things developed from non-living matter (ie. rocks, mud, rotting meat etc)

Who proved spontaneous generation false?

Francesco Redi (1626 – 1697)

Even though Redi disproved spontaneous generation it was not

accepted.

Why?

Louis Pasteur

Pasteur also dispelled the myth of spontaneous generation, proving that all life comes from pre-existing life (biogenesis).

What is the purpose of the curved neck flask in

Pasteur’s experiment?

Modern Scientific Theory: AbiogenesisThe Appearance of

Life on Earth Required:

• Formation of simple organic compounds

• Formation of complex organic compounds

• Enclosure of these organic compounds

• Growth, metabolism and reproduction

First Forms of Life

Prokaryotic Eukaryotic

Same Environment

Both live in Desert

Same Environment

Live in Different Environments

Plains vs Forest

Insects: longer probes to drink nectar

-wings to fly from flower to flower

Flowers: bright colours

Sweet smell

Cactus & Euphorb-both store water in stems and have spiny skin

Red fox: Red colour =blend to forest

Kit fox: Sandy colour = blend to plains, large ears for cooling

Two or more species live in close interaction with one another

Two or more

UNRELATED species become similar

Two or more

RELATED species become dissimilar

CoevolutionConvergentDivergent

PATTERNS OF EVOLUTION

Convergent Evolution

Divergent Evolution