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Evolution—change over time, the process by which modern species have descended from ancient organisms
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Darwin’s Theory of Evolution Who was Charles Darwin? http://www.pbs.org/wgbh/evolution /library/11/2/e_s_2.html
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Fossil—preserved remains of ancient organisms
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1. Geospiza magnirostris. 2. Geospiza fortis. 3. Geospiza parvula. 4. Certhidea olivawea
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Artificial Selection—selection by humans from natural variation among different organisms for breeding of useful traits
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Fig. 22-9 Kale Kohlrabi Brussels sprouts Leaves Stem Wild mustard Flowers and stems Broccoli Cauliflower Flower clusters Cabbage Terminal bud Lateral buds
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Other examples of Artificial Selection?
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Selective Breeding—method of improving a species by allowing only those individual organisms with desired characteristics to produce offspring
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Hybridization—breeding technique that involves crossing dissimilar individuals to bring together the best traits of both organisms
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Other example of hybridization?
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Genetic engineering—the process of making changes in the DNA code of living organisms Ex.-inducing mutations to increase genetic variation
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Fig. 17-6 (a) Tobacco plant expressing a firefly gene (b) Pig expressing a jellyfish gene
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Natural variation—genetic differences among individuals of a species Genetic variability starts with natural mutations
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Fig. 22-10
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Struggle for Existence— members of each species compete regularly to obtain food, living space, and other necessities of life
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Adaptation—any inherited characteristic that increases an organism’s chance of survival Camouflage as an example of evolutionary adaptaition
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Pandora Sphinx Moth Signate Melanophila Moth
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Luna Moth Polyphemus Moth
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A stick mantid in Africa A flower mantid in Malaysia
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Fig. 23-14a (a) Color-changing ability in cuttlefish
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STOP - 2/29
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Fig. 23-14b (b) Movable jaw bones in snakes Movable bones
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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
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Fitness—the ability to survive and reproduce viable offspring
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Descent with modification— principle that each living species has descended, with changes, from other species over time
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Common descent—principle that all living things have a common ancestor
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Homologous structures— structures that have different functions but develop from the same embryonic tissue
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Fig. 22-17 Humerus Radius Ulna Carpals Metacarpals Phalanges HumanWhale Cat Bat
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Vestigial organs—organs that serve no useful function
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Early development The early embryos of many animals with backbones are so similar that they can be hard to tell apart
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Fig. 22-18 Human embryoChick embryo (LM) Pharyngeal pouches Post-anal tail
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Biogeography The study of the past and present distribution of species
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