I. Darwin A. Original ideas: 1. Species are fixed/permanent 2. Earth is less than 10,000 years old...

I. Darwin

A. Original ideas:

1. Species are fixed/permanent

2. Earth is less than 10,000 years old

and relatively unchanging

B. Early Scientists1. Suggested Earth might be a lot older than a few

thousand years by looking at specific fossils &

certain living animals were similar but not exactly

alike

• 180 million years ago, Pangaea split in 2 land masses

• India collided with Eurasia just 40–50 million years ago, forming the Himalaya mountain range.

• The continents continue to drift today.

B. Scientists

2. Jean-Baptiste Lamarck (mid-1800s)

a. Proposed that life evolves/changes

b. Proposed that by using or not using a

body part, an organism develops certain

acquired characteristics- **thought these

could be passed on to offspring**

c. “Inheritance of Acquired Characteristics”

Lamarck’s Giraffe

C. Charles Darwin1. Mission:

to study the geology, plants, animals he encountered

on his voyage for 5 years

2. Ship was the H.M.S. Beagle

3. Focused on the Galapagos

Islands

4. Observations:

a. too many organisms are

produced

b. organisms vary

c. organisms struggle to

survive (fight for food,

mate, habitat, etc.)

d. the fittest for the environment survive

e. the fittest get to reproduce and pass on their

genetic traits

C. Charles Darwin3. Main Points:

A. Descent with modification-

organisms over long amount of time

will accumulate different

modifications to survive in

environment

B. Theory of Natural Selection individuals with inherited characteristics

well-suited for their environment survive to leave

more offspring on average than other individuals; “Survival of the fittest”

Descent with Modification

Survival of the fittest

D. Alfred Wallace (1858)

Came to same conclusion as Charles Darwin, sent Darwin his manuscript.

Darwin published his book, On the Origin of Species, in 1859.

Why didn’t he publish sooner?

Honey BadgerWHAT DOES IT MEAN “THE FITTEST”?

Butterfly

Sea Slug Glaucus atlanticus

Nudibranchs

Red Squirrel

Dogs vs. Wolves

Water Bears

Venezuelan Pitcher Plant

Hemeroplanes triptolemus

moth

Glasswing Butterfly

Camel

II. Evolution

Define “evolution”: gradual changes that have transformed

life over an immense period of time

A. Evidence of Evolution

1. Fossil record

2. Geographic Distribution- continental drift

3. Similarities in structures

4. Similarities in development

5. Molecular biology- DNA, proteins

B. Fossil Record1. A fossil is preserved remains or markings left

by organisms that lived in the past

2. Fossils are cast in sedimentary rock

Imprint

Mineralized

Frozen

Amber

Cast

C. Geographic Isolation

1. Traits of organisms are directly linked to the

geography and environmental conditions of

an area

D. Homologous Structures

1. Homologous Structures: different organisms that have similar bone structure

2.

E. Analogous Structures

1. Define: features of different species that are similar in

function but not in structure- are not derived from a

common ancestor, but evolved in response to similar

environmental challenge.

Examples2. Example: Insects and birds both have wings to fly, although their wing structure is very different structure. The fat-insulated, streamline shapes of seals (mammals) and of penguins (birds) is another example.

F. Vestigial Structures1. Vestigial Structures- remnants of structures that may have had important functions in an ancestral species but have no function currently

G. Similarities in Development

1. Embryos of closely related organisms

have similar stages in development

H. Molecular Biology1. Similar DNA suggests an evolutionary relationship

III. OTHER CONCEPTS IN EVOLUTION

A. Antibiotic- and Pesticide-Resistance

1. Antibiotic- medicine that kills/slows the

growth of bacteria

2. Some bacteria with natural resistance will

not be killed off by the antibiotics and can

re-grow a resistant population quickly

3. When pesticides are used, some insects will already have a natural resistance and survive the spraying, then reproduce more insects that inherit the resistance genes. Eventually the same pesticides will not have the same effect as before.

B. Artificial Selection1. Define: selective breeding

of domesticated plants

and animals to produce

offspring with genetic

traits that humans value

IV. Types of EvolutionA. Divergent Evolution: organisms that very

similar evolve to become very different

B. Convergent evolution:

when unrelated organisms evolve similar

adaptations because of similar environment

Ex: sharks and dolphins share analogous body plans, yet have different ancestral backgrounds

(fish versus mammal)