1. But don’t be fooled by these…
Analogous structures
look similar
on the outside
same function
different structure & development
on the inside
different origin
no evolutionary relationship
How is a bird like a bug?
Solving a similar problem with a similar solution

2. Analogous structures Dolphins: aquatic mammal Fish: aquatic vertebrate
both adapted to life in the sea
not closely related
Watch the tail!

3. They just came up with the same answer!
Flight evolved 3 separate times —
evolving similar solutions to similar “problems”
Convergent evolution
3 groups with wings
Does this mean they have a recent common ancestor?
They just came up with the same answer!
NO!

4. Because they used to walk on land!
Vestigial organs
Hind leg bones on whale fossils
Why would whales have pelvis & leg bones if they were always sea creatures?
Because they used to walk on land!

5. Comparative embryology
Development of embryo tells an evolutionary story
similar structures during development
all vertebrate embryos have a “gill pouch” at one stage of development

6. Building “family” trees
Closely related species are branches on the tree — coming from a common ancestor

7. 3. Geographical Distribution
Geographical distribution of living organims
Darwin concluded that the different finches found on the galapagos islands came from a common ancestor on the mainland – they adapted to different local environments
Organisms that live in similar environments have similar features

8. “descendants” of wild mustard
4. Artificial selection
How do we know natural selection can change a population?
we can recreate a similar process
“evolution by human selection”
“descendants” of wild mustard

9. “descendants” of the wolf
Selective Breeding
Humans create the change over time
“descendants” of the wolf

10. Artificial Selection gone bad!
Unexpected consequences of artificial selection
Pesticide resistance
Antibiotic resistance

11. Insecticide resistance
Spray the field, but…
insecticide didn’t kill all individuals
variation
resistant survivors reproduce
resistance is inherited
insecticide becomes less & less effective
The evolution of resistance to insecticides in hundreds of insect species is a classic example of natural selection in action.
The results of application of new insecticide are typically encouraging, killing 99% of the insects.
However, the effectiveness of the insecticide becomes less effective in subsequent applications. The few survivors from the early applications of the insecticide are those insects with genes that enable them to resist the chemical attack. Only these resistant individuals reproduce, passing on their resistance to their offspring. In each generation the % of insecticide-resistant individuals increases.

13. Any Questions??
Original presentation by Kim Foglia