What do you see in this picture?

Fossils Anatomy Development Biological

Molecules Models Examples

FOSSILSPreserved or

mineralized remains

Studied by Paleontologists

Fossils are structures formed from…

An animal is buried by sediment Burial takes place on the ocean

floor, in swamps, in mud, or in tar pits

The tissue is replaced by harder minerals

FOSSILS Fossils found in

older rock are different from those found in newer rock

The further you dig down, the longer ago the species lived on earth

Horseshoe crab: still alive today!

550 million years old: Ediacara – oldest animal fossil

FOSSILS Radiometric dating:

measure radioactive isotopes

Half-life: time it takes for ½ of a given amount of radioisotope to decay

Comparing Anatomy

Homologous: Similar structural setup that likely evolved from a common ancestor.

Examples: Human arm, cat leg, whale fin, bat wing

Comparing Anatomy

Analogous: Structures that are similar in function but not inherited from common ancestors

Examples: Pterodactyl, bat, bird & insect wings

Comparing Anatomy

Vestigial: Structures reduced in size from lack of use

Examples: tailbone, appendix, python hip, whale legs

Anatomy: Vestigial Structures Blind Mole Rat

Eyes covered with a thin layer of skin

Anatomy: Embryology

All vertebrates have…

Dorsal hollow nerve cord

Notocord Gill slits Post anal tail

Biological Molecules

All living things have the same 4 base pairs in their DNA

Amino acid similarities between organisms The more differences there are, the

further your common ancestor was

Speed of Evolution

Gradualism; slowly over a long period of time

Punctuated equilibrium; rapid burst of changes followed by periods of little change

SpeciationThe process by which new organisms form

Adaptive Radiation The evolution

of many different species from a single ancestor to occupy many different niches

Modes of Evolution Co-Evolution: 2 or more species

that interact and evolve together EX: Plants & their pollinators

Convergent Evolution Unrelated organisms living in similar

ecosystems developing similar traits Marsupials in Australia compared to

other mammals Analogous structures develop:

similar function, different structures Bat wing and an insect wing

Divergent Evolution Related organisms evolving into new

and different species Darwin’s finches, Hawaiian fruit flies

Homolgous structures develop: show a similar ancestry Whale fin and a human arm

Adaptations

The process by which an organism becomes better suited to its environment Attract mates Avoid predators Capture prey Blend into environment, camouflage Compete against another species for resources

Remember: competition arise when 2 or more population

occupy the same niche

Classification of Living Things

All living things are grouped by similarities

The “tree of life” shows how all living things are connected

What if…There are so many unanswered questions

Ponder this….

Scientists

Lamarck: Theory of Acquired Characteristics Use & Disuse

Scientists

Charles Darwin Theory of

Evolution by means of Natural Selection

Scientists

Variation exists in a population Organisms compete for resources More offspring are born than can survive The offspring with the favorable traits are

more likely to survive and pass on those traits Survival of the Fittest

Scientists

Traveled to the Galapagos Islands Observed many different species of finches

that all occupied different niches