What do you see in this picture?

Fossils Anatomy Development Biological Molecules Models Examples

FOSSILS Preserved 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

Speciation The 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