Evolution

Ch 14

How did it begin?

• Big bang theory: Stars were formed from Hydrogen Atoms (At.#1). As they go through nuclear reactions other elements are made. At the same time the universe expands. We are all made of star dust.

When did life begin on Earth?

• 4.5 billion years ago. Earth was a lifeless, hot, volcanic place. As it cooled the conditions were correct for life to begin.

Read and Scroll

ThroughIt all!

How do we know how old the earth is?

• Radiometric Dating. Radioactive isotopes lose particles. The amount of neutrons lost over a period of time = the age of the item.

What was the first theories of how life began?

• The thought that living things could arise from nonliving things this was called Spontaneous Generation.

What is the current theory of how life emerged?

• Biogenesis: Life comes from life

Francesco Redi’s Experiment

Lazzaro Spallanzani

Louis Pasteur

Louis Lerman’s Bubble Model• Ammonia(NH3) and Methane(CH4) are

produced by underwater volcanoes. As the gas escapes, it is trapped in bubbles creating Amino Acids.

• Bubbles burst on surface and A.A. are further energized by lightning and radiation.

• Organic molecules become increasingly complex.

The Miller Urey Experiment

1920’s A.I. Oparin’s “primordial soup” model

What about the plasma membrane?

• Amino Acids tend to create ball like structures called microspheres. These may have been the early plasma membranes that led to cells. Other substances do this as well.

The development of life forms• Prokaryotes- oldest life form. 3.5

billion year old fossils. Archae -> Eubacteria. Eukaryotes 1.5 billion years ago with Kingdom Protista. Unicellular -> Multi cellular 700 million years ago.

• Animals developed• Plants and Fungi Developed

Lab Review

Time-scale of life.The Geologic, Time and Biologic Events

Cyanobacteria at work(prokaryote that modern chlorphyll evolved from)

• Cyanobacteria is responsible for half the worlds oxygen. This also lead to the protective ozone layer O3 which blocks out harmful ultraviolet radiation.

What happened to all of these ancient life forms?

• Five Mass Extinctions. In the third mass extinction 245 million years ago 96% of all species of animals became extinct.

• Is another mass extinction occurring now?

Environmental changes increase Natural Selection

• Natural selection: those best fit for an environment survive and reproduce. (Example: Shark Vs. Dodo bird)

Jacanas And

Polyandry

Who developed the theory of Natural Selection?

Charles Darwin 1859 published On the Origin of Species by Means of Natural Selection after a 5 year boat ride around the southern hemisphere on the HMS Beagle.

Galapagos Islands were inspirational because of the unique animals there. Fig 15-4

Peacocks

Evidence for Evolution• Fossils Fig. 15-1• Nucleic Acid (99% same DNA; humans and chimps)• Body structures

– Vestigial (non-used body parts)– Homologous structures (all species that came from

the same ancestor have these parts) Fig. 13-13• Embryonic Development Fig 13-14

Whale evolutionDNA

How does Evolution Really Work?

• Wooly Worm Lab: After Video

Humming Bird Evolution

Micro Vs. Macroevolution• Microevolution when small gene changes

occur. These create small changes in a population or species over time. – The species is the same, but the allele

frequencies may have changed. • Macroevolution is evolution on a grand scale.

This evolution is extreme and changes species. – The splitting of one species into two.

Human Evolution

For Extra Credit outline Ch 17!An opportunity of a life time!!!

Did Humans EvolveLaetoli Foot Prints

&Finding Lucy

Computer Lab

PolenpeepersEvolution

Draw a map of the Polenpeepers homeland and islands. Explain what happened to each group of Polenpeepers. Be sure to include a time frame.

How do scientists know so much about the Polenpeepers?

What did this lab illustrate? How?