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

I. History

A. Original ideas:

1. Species are fixed/permanent

2. Earth is less than 10,000 years old

and relatively unchanging

B. Early Scientists

1. Georges Buffon (mid-1700s) French naturalist

a. Suggested Earth might be a lot older than a few

thousand years

b. Specific fossils & certain living

animals were similar but

not exactly alike

B. Scientists

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

a. Proposed that life evolves/changes

b. Explained evolution as a process of

adaptation

c. Proposed that by using or not using a

body part, an organism develops

certain acquired characteristics-

**thought these could be passed on

to offspring**

d. Called “Inheritance of Acquired

Characteristics”

Lamarck’s Giraffe

B. Scientists

3. James Hutton (1700s)

A. Two conclusions:

i. Slow processes from mountain building &

erosion suggest Earth is very old

ii. Slow/gradual change occurring over vast

amounts of time cause enormous change

on Earth

4. Charles Lyell (mid-1800s)

A. wrote influential book Principles of Geology;

B. proposed that gradual and observable

geologic processes such as erosion could

explain the physical features of today's Earth

About 180 million years ago, Pangaea split into northern and southern land masses that later separated into the modern continents. India collided with Eurasia just 40–50 million years ago, forming the Himalaya mountain range. The continents continue to drift today.

B. Scientists

5. Thomas Malthus

(mid-1700 to mid-1800s)

A. Reasoned that if human

population growth was left

unchecked, sooner or later there

would be insufficient living space for

everyone and we would bring on our own

population control

C. Charles Darwin1. Mission:

to study the geology, plants, animals he

encountered on his voyage; H.M.S. Beagle; focused

on the Galapagos Islands

2. Observations:

a. too many organisms are

produced

b. All individuals in a species have

variation

c. All individuals must struggle for

existence, and those with favorable

variation have an advantage over

others (fight for food, mate, habitat,

etc.)

d. Variation is heritable time produce

new species.

e. Successive inheritance of favorable variation over vast stretches of geological time produce new species.

C. Charles Darwin3. His Main Points:

A. Descent with modification-

organisms spread

out over millions of years and

accumulate different modifications

to diverse ways of life

B. Theory of Natural Selection- process by

which individuals with inherited characteristics

well-suited for their environment survive to leave

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

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

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?

EVOLUTION

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

THE FOSSIL RECORD

3. Dating Fossils i. Radiometric Age

- Measurement of isotopes in objects

ii. Relative Age- Age based on

layers

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 Structures

1. 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

2. Hemoglobin

3. Cytochrome C

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 Evolution

A. Divergent Evolution: consequence of adaptive radiation- organisms sharing a common ancestor evolve to become different according to environmental pressures

Adaptive Radiation

B. Convergent evolution: arises when there are some sort of ecological or physical driver toward a similar solution, even though the structure or function has arisen independently.

Ex: sharks and dolphins share

analogous body plans, yet have

different ancestral backgrounds

(fish versus mammal)