Evidence for Evolution Review

Hour 2 Trimester 3

Common Descent

• We have five pieces of evidence for this idea:1. Homologous Structures2. Fossil record3. Geographic distribution of similar species4. Similarities in early stage of development5. Similarities in genetic sequences, DNA

The fossil record- some organisms went through drastic change while others went extinct or stayed relatively the same over time.

Geographic distribution of living species

The presence of similar but unrelated organisms in similar environments suggests the action of natural selection

Homologous structureshave different mature forms but develop from

the same embryonic tissues. (Some homologous structures no longer serve major roles in descendants. If the structures are greatly reduced in size, they are called vestigial organs.

Similarities in early development

The early stages, or embryos, of many animals are very similar.

DNA Similarities• Many sequences of DNA show common

descent of organisms. These pieces of matching DNA code for traits found in animals that are closely related.

Fossil Record:

The collection of all of the known remains of ancient species

Geographic Distribution:

• Evidence for common ancestry because it shows that organisms in similar environments can adapt to their environments in similar ways. Environment affects species’ traits.

Homologous Structures

• Different mature forms (and functions) from the same embryonic tissues.

Co-evolution:

• is when a species directly influences the evolution of another species and both populations evolve in parallel.

Cladogram:

Adaptive radiation

the pattern of adaptation that isolates a species into two separate lineages

Flash Cards:

•Evolution •Artificial selection•Natural selection•Variation•Competition•Fossil Record•Embryology

• Common ancestry• Adaptive radiation• Co-evolution• Geographic

Distribution• Homologous

Structures• Vestigial Organs