Unit 8—Evolution AP Biology

I. Evolution and Evolutionary

A.Evolution—change in gene frequency in a population over timei. Change must be genetic

ii. Occurs in a population—not individuals

iii. Time depends on how fast environment changes and how fast organisms reproduce

B. Evolutionary Theory—diversity of organisms on earth is due to evolution from simple to complex

II. Hypotheses about Origins of Life

Resources for these notesBozeman Video—Abiogenesishttp://www.bozemanscience.com/010-abiogenesis

Campbell Textbook—Ch. 25.1Ch. 25.3

II. Hypotheses about Origins of Life

A. Spontaneous Generation—thought that life could form from non-living things 1862—Pasteur disproved this idea through

is experiments

II. Hypotheses about Origins of LifeB. Organic Molecules—Building

Blocks of Life

i. 1st Organic Molecules made in lab—Miller-Urey 1953

Early earth—reducing environment

Energy—from lightning, UV,…(no ozone yet)

Experiments with these conditions created amino acids (abundantly)…also sugars, lipids, & nitrogenous bases

II. Hypotheses about Origins of Life

ii. Polymerization—putting pieces together to make macromolecules! Researchers have made polypeptides

without enzymes.

Dehydration by vaporization—drip amino acids on hot sand, clay or rock

II. Hypotheses about Origins of Life

iii. Membranes—lipids spontaneously form spheres—enclose liquids and form a membrane (Protobionts / Protocells)

II. Hypotheses about Origins of Life

iv. 1st Genetic Material Life needs replication and replicating

molecules

1st genes were RNA—which can replicate (“RNA World”)

Ribozymes—RNA catalysts—assembled amino acids and replicated RNA (no enzymes or ribosomes yet)

II. Origins of Life

C. Prokaryotic Cells—First Fossils are apprx. 3.5 billion years old

2 Domains—Archaea and Bacteria

2 Hypothesis about how they got their energyTook ATP from environment

Made ATP from sulfur and iron

II. Origins of Life

First fossils are apprx. 2.1 billion years old

Membrane enfolding and Endosymbiosis (Review!)

D. Eukaryotic Cells

III. Developing Ideas about Evolution

ResourcesCampbell Textbook

Ch. 22

III. Developing Ideas about EvolutionA. Ancient Ideas

i. Anaximander– Greek; 500BC; thought perhaps simple things developed into more complex forms

ii. Aristotle—Greek; 384-322BC; believed that species are “fixed”; created separately and could not be changed

iii. Other cultures—each culture had an explanation (varied)

III. Developing Ideas about Evolution

B. Mid-1700’s– Geology presented several big ideas…

Earth is older than 6000 years old

Early 1800—Lyell—Principals of Geology—gradual forces shape the earth rather than catastrophes

Collections of fossils—found ocean fossils on mountain tops—perplexed scientists…

Sir Charles Lyell

III. Developing Ideas about Evolution

C.Lamarck/Wallace Lamarck-Published essay in 1809

“Inheritance of Acquired Characteristics”-changed due to use/disuse and developed traits could be passed on…

Wallace-Published essay in 1858

Natural selection-slow modification-didn’t apply to humans

Alfred Wallace

Jean Baptiste-Lamarck

III. Developing Ideas about Evolution

D. Darwin—Wrote essay in 1844 but published it in 1858

i. Darwin’s Voyage—HMS Beagle 1831-1836—Some observations made on the voyage

1. Similar adaptations occurred in similar environments

2. Great diversity within the same environment (ex. Galapagos finches)

3. Fossils—Darwin developed a large collection

III. Developing Ideas about Evolution

Charles Darwin and HMS Beagle Voyage

III. Developing Ideas about Evolution

ii. Darwin’s Explanation—Decent with Modification

1. Did not use the term evolution

2. No supernatural—all based upon what was seen in the natural world

3. Developed ideas while on HMS Beagle—highly influenced by Malthus, Lyell, and other scientists

4. Basic idea was that organisms change over time…main mechanism is natural selection…particularly for adaptive change

III. Developing Ideas about Evolution

Timeline of Scientific Ideas about Geology, Inheritance, Evolution, and Population Limits

IV. Natural Selection and Artificial Selection

Resources Bozeman—Natural Selection

http://www.bozemanscience.com/001-natural-selection

Campbell Textbook Ch. 23

Learn Genetics http://learn.genetics.utah.edu/content/selection/artificial/

IV. Natural Selection and Artificial Selection

A. Natural Selection–organisms with certain inherited traits tend to survive and reproduce at higher rates in their environment than other individuals because of those traits.

1. Differential Reproduction—organisms overproduce -> not all survive -> those better suited for environment survive -> Reproduce more

Reproduction is what matters—ensures passing on of genes

“Better suited” to survive, not “best”… really survival of the good enough…

Conditions of environment determine if fit enough

IV. Natural Selection and Artificial Selection

2. Adaptation—genetic trait that helps an organism reproduce

(variations sometimes turn into adaptations, but not always)

3. Relative Fitness—the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

**Likelihood of reproducing and passing on genes

IV. Natural Selection and Artificial Selection

IV. Natural Selection and Artificial Selection

B. Artificial Selection– humans determine who reproduces Can create more change in short period of time

May create artificial environment for artificially selected organisms to survive