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

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

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!

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!

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

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

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

“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

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

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

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.

Any Questions?? Original presentation by Kim Foglia