Era Period Time

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

(millions of years ago)Era Period Time

(millions of years ago)Era Period Time(millions of

years ago)

290 – 245

363–290

410–363

440–410

505–440

544–505

1.8–present

65–1.8

145–65

208–145

245–208

Quarternary

Tertiary

Cretaceous

Jurassic

Triassic

Vendian 650–544

Section 17-1

Figure 17-5 Geologic Time Scale

Go to Section:

Aim: How do we know that evolution happened ?

Geologic Time Scale

If we could follow the fossils of a particular organism up through the layers of the Earth we would have a clear picture of how organisms changed over time

General trend in equid

body size over millions

of years

While such trends as toe reduction and increase in size are real over time, the rate of change varied among different branches of the equid evolutionary bush

The cladogram graphically represents a

evolutionary process

Phylogenetic tree of the evolutionary relatedness of organisms

Anatomical comparisons indicate the similarities in bone structure suggests a common ancestor

Comparative Embryology

Similarity of embryos during development suggests a common ancestor.

What are these embryos?

Comparative Embryology

Similarity of embryos during development suggests a common ancestor.

Aligned DNA fragment and first chromosome banding patterns for man (Homo sapiens),

chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla),

and orangutan (Pongo pygmaeus).

This cladogram shows that..

………Humans share a common ancestor with other primates, we did not evolve

from them

Prepare a refute to this situation

• Someone tells you that they are teaching that humans evolved from monkeys.

Aim: What paths did evolution follow?

• DIVERGENT EVOLUTION"One ancestral stock evolves into two species, which continue to evolve and become less and less alike over time."

• PARALLEL EVOLUTION"In PARALLEL EVOLUTION two related species arise from a common ancestor. The two species then evolve in much the same way over time, probably in response to similar environmental selection pressures."

• "CONVERGENT EVOLUTION occurs when two or more groups that are not closely related come to resemble each other more and more as time passes. This is usually the result of occupation of similar habitats and the adoption of similar environmental roles.."

• Punctuated equilibrium

• This type of diagram reflects the theory that evolution has not occurred at a constant rate, rather it has occurred in short bursts with long periods of stability between. This theory explains the absence of the infinite range of intermediate fossils in branches of evolution such as the vertebrates.

Evolution of the Whale

Started on Land and moved to the Sea

What happened to the Dinosaurs?