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

ancient organisms

Darwin’s Theory of Evolution

Who was Charles Darwin?

http://www.pbs.org/wgbh/evolution/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. 22-9

Kale

Kohlrabi

Brussels sprouts

Leaves

Stem

Wild mustard

Flowersand stems

Broccoli

Cauliflower

Flowerclusters

Cabbage

Terminalbud

Lateralbuds

• 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. 17-6

(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. 22-10

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. 23-14a

(a) Color-changing ability in cuttlefish

STOP - 2/29

Fig. 23-14b

(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. 22-17

Humerus

Radius

Ulna

Carpals

Metacarpals

Phalanges

Human WhaleCat 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. 22-18

Human embryoChick embryo (LM)

Pharyngealpouches

Post-analtail

Biogeography

The study of the past and present distribution of species