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