One of the key differences between experts and novices is an experts ability to recognize important information from less important information. Today: Evolution and Humans

Evolution: A species’ genetic component changes as the individuals reproduce

As DNA changes; traits change. Protein

Reproductive success = evolutionary success

Natural Selection: Individuals that are most successful at reproducing will pass on more of their genetic information.

For natural selection to take place the following conditions must be met… Not all individuals can reproduce Genetic diversity gives rise to individuals with different traits

Fig Genetic diversity is needed for natural selection to occur. Reproduction/ Selection

Environmental changes drive evolution.

Fig mya 180 mya 65 mya135 myacurrent Plate Tectonics

The environment is in constant flux

Fig 26.5 Changing environment can separate populations and lead to new species…

Flies raised in different environments prefer to mate with individuals from the same environment... Separation does not need to be geographic

Flies raised in different environments prefer to mate with individuals from the same environment...

Individuals are selected… But species evolve via changes in DNA during reproduction.

Who evolves?…Species. A population that can produce fertile offspring A population that does reproduce **A population sharing genetic information** A. harrisi A. leucurus See Section 26.1

Horse Mule Donkey X =

Horse Mule (sterile) Donkey X = So…horses and donkeys are not the same species.

Who evolves?…Species. A population that can produce fertile offspring A population that does reproduce **A population sharing genetic information** A. harrisi A. leucurus See Section 26.1

Artificial Selection

from TeosinteMaize By artificial selection that began ~10,000 years ago. Fig 30.3

Different foods from one species of plant. Created by artificial selection.

Wild member of Brassica oleracea: small side buds Brussels sprouts: extremely large side buds Artificial selection Number of Individuals Size of buds (cm) Select individuals that have the largest side buds and breed them. 2. Of the offspring, select individuals that have the largest side buds and breed them. 3. Of the offspring, select individuals that have the largest side buds and breed them. 4. After several generations, bud size increases dramatically. Fig 1.3

DNA is passed from generation to generation, and therefore can tell us about relationships between species. Fig 34.40

How are we related to our ancestors, and where did we come from? Fig 34.42