1. BIO 111: Foundations of Biology
Unity and Diversity

2. Unity

3. A. Made of the same stuff: Biomolecules in water
Unity
A. Made of the same stuff: Biomolecules in water

4. A. Made of the same stuff: Biomolecules in water
Unity
A. Made of the same stuff: Biomolecules in water
B. The molecules are organized into the same units: cells
Why are cells small?

5. Why such extraordinary similarity?
Unity
A. Made of the same stuff: Biomolecules in water
B. The molecules are organized into the same units: cells
C. The cells work in largely the same ways:
energy conversion through ATP
protein synthesis by reading DNA
replication by division
O.R.R.G.E.E.
Why such extraordinary similarity?

6. Unity
II. Diversity
Bacteria

7. Unity II. Diversity Bacteria Archaea

8. Unity
II. Diversity
Bacteria
Archaea
Eukarya

9. Why such extraordinary similarity? Why such extraordinary diversity?
Unity
II. Diversity
Bacteria
Archaea
Eukarya
Why such extraordinary similarity?
Why such extraordinary diversity?

10. Why such extraordinary similarity? - Divergence from Common Ancestors
Unity
II. Diversity
III. Evolution
Why such extraordinary similarity? - Divergence from Common Ancestors
Why such extraordinary diversity? Genetic Variation and Natural Selection

11. Unity II. Diversity III. Evolution
The unity allows us to explain the diversity: all organisms have inherited DNA from their ancestors. The more similar the DNA, the less time has elapsed for mutational differences to accumulate (and the more recent their common ancestry).

12. Unity
II. Diversity
III. Evolution
The unity allows us to explain the diversity: all organisms have inherited DNA from their ancestors. The more similar the DNA, the less time has elapsed for mutational differences to accumulate (and the more recent their common ancestry).
We can use the number of genetic differences between species to estimate the amount of time that they have been diverging (molecular clock).

13. Another independent source of evidence regarding evolution: the fossil record

14. Earth History
Life’s Diversity
1.8 bya: first eukaryote
0.7 bya: first animals
0.5 bya: Cambrian
0.25 bya: Mesozoic
0.065 bya: Cenozoic
4.6 bya: Earth Forms
4.0 bya: Oldest Rocks
3.8 bya: Oldest Fossils
bya: O2 increase

15. Thousands of Genera Millions of Years Ago
All genera
“well described” genera
The “big five” Mass Extinction Events
Thousands of Genera
Millions of Years Ago

16. Another independent source of evidence regarding evolution: the fossil record

17. Unity
II. Diversity
III. Evolution
Here is the ‘tree’ based on genetic similarity among existing species and the ‘hypothesis’ of common ancestry.
We can use transitional fossils to test this hypothesis. Only evolution predicts that a transitional fossil, which is a third, different species from the descendants, should have existed at a time predicted by the genetic similarity of their descendants. (If they are unrelated and genetic similarity is NOT a function of common ancestry, then these ‘transitional species’ are just weird, goofy species; not the common ancestors. And they could thus have lived at any time in the past – not just where evolution predicts.

18. Unity
II. Diversity
III. Evolution
Fossils of transitional forms are consistent with these genetic predictions.
Tiktaalik – 375 mya
Archaeopterix – 150 mya
Australopithecus – 4.5 mya

19. Unity
II. Diversity
Evolution
The Functional Significance of Diversity

20. The Functional Significance of Diversity A. Cellular Level
Unity
II. Diversity
Evolution
The Functional Significance of Diversity
A. Cellular Level
What is the effect of cellular diversity?
How do these differences arise?

21. Genetic Differentiation

22. Unity
II. Diversity
Evolution
The Functional Significance of Diversity
A. Cellular Level
B. Ecological level
What is the effect of species diversity?
How do these differences arise?

23. All biological systems are complex assemblages of structurally and functionally different subunits.
This DIVERSITY increases functional ability and efficiency (division of labor)
Ultimately, as the system evolves this complexity, it becomes more and more dependent on that diversity to function:
How well do human cells do with poorly functioning mitochondria?
How well does a human do with poorly functioning red blood cells?
How well does a population do with no reproductive adults?
How well does an ecosystem do with no predators?
System Components
Organelle different molecules
Cell different organelles
Organ different cell types
Organism different organs
Population different organisms
Community different species
Ecosystem producers, heterotrophs,
decomposers