chapter 16.4 (pgs. 465- 473): evidence of evolution

Chapter 16.4 (Pgs. 465-473):Evidence of Evolution

Biogeography

- Is the study of where organisms live, now and historically

- Patterns in distribution of living and fossil species can show evolutionary patterns

- Two patterns:1) Closely related but different species

live in slightly different habitats2) Distantly related but similar species

live in similar habitats around the world

Age of the Earth- Was proposed by geologists to

be much older than 6000 yrs old

- In 1860s, radioactivity was discovered

- Used to determine age of rocks and fossils

- Is 4.5 billion years old- This provided enough time for

evolutionary change to occur

Fossils

- Show the record of extinct species

- Show how intermediate forms connect extinct and living species

Anatomy and Physiology

Anatomy and Physiology- Can show relationships to a

common ancestor

- Homologous Structures- Are similar structures- Can be used for different functions- Come from a common ancestor

- Analogous Structures- Are similar structures- Are used for the same function- Are found in unrelated organisms

Homologous structures show how closely related organisms are

Anatomy and Physiology

- Vestigial Structures- Are inherited from ancestors- Have lost most of their function

- Embryology- Similar patterns of development

show that organisms are related to a common ancestor

Genetics and Molecular Biology- Common Genetic Code

- DNA is universal among all organisms, which indicates a common ancestor

- Homologous Molecules- Enzymes, hormones, and other

important molecules are similar between organisms, which indicates a common ancestor

Testing Natural Selection- Has been shown in Galapagos finches

- They gave beaks with different sizes and shapes

- Changes in the food supply creates selection pressure on beak size

- Only larger seeds are available during a drought, and only birds with larger beaks can eat them

- Birds with smaller beaks starve during a drought