Evolution—change over time, the process by which modern species have descended from ancient organisms

Darwin’s Theory of Evolution Who was Charles Darwin? /library/11/2/e_s_2.html

Fossil—preserved remains of ancient organisms

1. Geospiza magnirostris. 2. Geospiza fortis. 3. Geospiza parvula. 4. Certhidea olivawea

Artificial Selection—selection by humans from natural variation among different organisms for breeding of useful traits

Fig Kale Kohlrabi Brussels sprouts Leaves Stem Wild mustard Flowers and stems Broccoli Cauliflower Flower clusters Cabbage Terminal bud Lateral buds

Other examples of Artificial Selection?

Selective Breeding—method of improving a species by allowing only those individual organisms with desired characteristics to produce offspring

Hybridization—breeding technique that involves crossing dissimilar individuals to bring together the best traits of both organisms

Other example of hybridization?

Genetic engineering—the process of making changes in the DNA code of living organisms Ex.-inducing mutations to increase genetic variation

Fig (a) Tobacco plant expressing a firefly gene (b) Pig expressing a jellyfish gene

Natural variation—genetic differences among individuals of a species Genetic variability starts with natural mutations

Fig

Struggle for Existence— members of each species compete regularly to obtain food, living space, and other necessities of life

Adaptation—any inherited characteristic that increases an organism’s chance of survival Camouflage as an example of evolutionary adaptaition

Pandora Sphinx Moth Signate Melanophila Moth

Luna Moth Polyphemus Moth

A stick mantid in Africa A flower mantid in Malaysia

Fig a (a) Color-changing ability in cuttlefish

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Fig b (b) Movable jaw bones in snakes Movable bones

Question: What would happen if a well-adapted population experienced a sudden major change in its environment Answer: If the population had a variety of traits some of them may survive and reproduce in the new environment, if not they would probably become extinct

Fitness—the ability to survive and reproduce viable offspring

Descent with modification— principle that each living species has descended, with changes, from other species over time

Common descent—principle that all living things have a common ancestor

Homologous structures— structures that have different functions but develop from the same embryonic tissue

Fig Humerus Radius Ulna Carpals Metacarpals Phalanges HumanWhale Cat Bat

Vestigial organs—organs that serve no useful function

Early development The early embryos of many animals with backbones are so similar that they can be hard to tell apart

Fig Human embryoChick embryo (LM) Pharyngeal pouches Post-anal tail

Biogeography The study of the past and present distribution of species