7.2-7.4 evidence for evolution

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

The Development of Life: Evolution

How old is the Earth?

How many years ago life originated on Earth?

Geological time scale

Earth came into being approximately   4,6 * 10^9  years ago

 

First single-celled organisms emerged approx. 3.8 * 10 ^ 9 years ago in the PRECAMBIUM

First multicellular organisms emerged approx. 670 * 10 ^ 6 years ago

First land plants: approx. 400 * 10 ^ 6 years ago in DEVOON

First vascular plants: approx. 350 * 10 ^ 6 years ago

First dinosaurs (reptiles): approx. 250 * 10 ^ 6 years ago in the MESOZOICUM (Triassic, Jurassic and Cretaceous)

Mass extinction dinosaurs: 65 * 10 ^ 6 years ago; start CENOZOICUM, mammals become dominant

First hominins: approx. 5 * 10 ^ 6 years ago

Interesting structures

• Homologous: divergent evolution
  similar origin, different function
• Analogous: convergent evolution
  different origin, similar function

Vestigial organs

No apparent function, residual parts of an ancestor

Memphis Depay

Species

A group of organisms with similar features which can interbreed to produce fertile offspring, and which are reproductively isolated from other species

Speciation:

1. part of a population becomes separated from the rest of the species.

2. adaptation to different environmental conditions.

3. reproductive isolation. As long as the two groups interbreed they share the same gene pool and remain the same species.

Phylogenetic tree

Tips for reading trees

• Same, but different style
  
  
  
  
• Same, but turned at 
  branching point 

Work to be done

7.2-7.4 : Questions 19 – 22, 24 – 26, 28 – 34

and Concept lists 7.2, 7.3 and 7.4

Question:

What is the evidence for evolution? Watch the video and write down the evidence they found that supports the theory of evolution.

Question:

What is the evidence for evolution? Watch the video and write down the evidence they found that supports the theory of evolution.

Great similarity between species implies

1. Recent common ancestry
2. Remote common ancestry
3. Succesfull reproduction
4. Extinction

According to this tree, sharks are MOST closely related to which organism?

1. amphibians
2. ray-finned fish
3. primates
4. birds

According to this tree, birds are LEAST closely related to which organism?

1. amphibians
2. ray-finned fish
3. primates
4. sharks

What is the most recent common ancestor of C and D?

1. 1
2. 2
3. 3
4. 4