Survival of the fittest EVOLUTION “Change over time” Natural Selection Darwin Survival of the fittest

How did the giraffe get its long neck? Before Darwin….. Lamark stated that organisms evolve

Lamark’s ideas: evolution was driven by an inner “need” acquired characteristics could be passed to the next generation Lamarck was rejected because his mechanism by which evolution occurred was not supported by DATA

BUT populations tend to remain stable Darwin Observation #1 More offspring are produced that can possibly survive. BUT populations tend to remain stable AND there are limited resources

SO the inference is: There is a struggle for survival between individuals of a population and not all will survive Aphaenogaster tipuna ants fighting over food

Much of this variety is inherited OBSERVATION #2 Organisms display a lot of variety in their characteristics Much of this variety is inherited

Inference #2: Those individuals whose inherited traits best fit them to their particular environment will leave more offspring

Inference #3: This unequal ability of individuals to survive and reproduce will cause a gradual change in the population Favorable characteristics will accumulate in the population over time

by means of Natural Selection Key ideas of Evolution by means of Natural Selection Individuals DO NOT EVOLVE. Populations evolve Evolution is not caused by a NEED of an individual. Surviving does not contribute to evolution alone. There also has to be reproduction Acquired characteristics are not passed down to the next generation. Adaptations depend on the environment

EVIDENCE OF EVOLUTION

FOSSIL RECORD

Fossils provide evidence of the change of life throughout time

Comparative Anatomy HOMOLOGOUS STRUCTURES

Anatomical Homologous structures: indicators of a common ancestor Show divergent evolution

vestigial structures Structures with no or little function in organism

Embryological homologies

Molecular Homologies Compare DNA sequences or proteins (amino acid sequences) The more differences the longer ago the two species diverged from a common ancestor

Analogous structures Evolved independently and don’t indicate close relationships

A) Divergent evolution  results in homologous structures B) Convergent evolution  results in analogous structures

Microevolution Generation to generation change in the frequencies of alleles in the gene pool Causes: natural selection Genetic Drift: changes in allele frequencies due to chance Gene flow immigration or emigration of individuals (and their genes) Mutation introduces new alleles

blue people of troublesome creek Examples of Genetic Drift Natural disaster wipes out a portion of a population Example #2 Relatively few individuals start a new population in isolation founder effect blue people of troublesome creek

Selection types stabalizing disruptive directional

Directional Selection Peccaries are great predators of cacti Peccaries are great predators of cacti = original population = population after introduction of peccaries

stabilizing selection Parasitic wasps lay eggs at the base of the spines. Hatched larva feed on the cactus

Disruptive selection

Identify selection types acting on these organisms

Key idea: reproductive isolation Biological Species Population or group of populations that have the potential to interbreed with each other in nature and produce viable offspring Key idea: reproductive isolation

Fig. 14-3

Fig. 14-3a Habitat isolation

Fig. 14-3b Behavioral Isolation

Behavioral Isolation

Fig. 14-3c Mechanical Isolation

Fig. 14-3d Gametic Isolation

Hybrids do not develop into fertile adults Fig. 14-3e Postzygotic Barriers Hybrids do not develop into fertile adults

National Geographic http://www.youtube.com/watch?v=1zOWYj59BXI

Speciation is the formation of a new species Often it comes about because of some kind of geographic barrier

Adaptive radiation is a type of speciation

Phylogenetic trees

Which finch is most closely related t the Green warbler finch? Cactus ground finch Small tree finch Medium tree finch Woodpecker finch Medium ground finch Small ground finch Large cactus ground finch Vegetarian finch Large tree finch Mangrove finch Green warbler finch Large ground finch Sharp-beaked ground finch Seed eaters Cactus flower eaters Bud eaters Insect eaters Ground finches Tree finches Warbler finches Is the medium ground finch more closely related to the small ground finch or to the large ground finch? Which finch is most closely related t the Green warbler finch?

Beastie Activity

Common ancestral carnivorans Polar bear Asiatic black bear American black bear Giant panda Brown bear Sun bear Sloth bear Spectacled bear Lesser panda Raccoon Pleistocene Pliocene Miocene Ursidae Procyonidae Oligocene Common ancestral carnivorans Figure 15.12A

THE DOMAINS OF LIFE For several decades, scientists have classified life into five kingdoms MONERA PROTISTA PLANTAE FUNGI ANIMALIA Earliest organisms Figure 15.14A

A third domain, the Eukarya, includes all kingdoms of eukaryotes A newer system recognizes two basically distinctive groups of prokaryotes The domain Bacteria The domain Archaea A third domain, the Eukarya, includes all kingdoms of eukaryotes BACTERIA ARCHAEA EUKARYA Earliest organisms Figure 15.14B

Organisms are grouped into progressively larger categories (taxons) Table 15.10

CLASSIFICATION (TAXONOMY) DOMAIN KINGDOM PHYLUM \ CLASS ORDER FAMILY GENUS SPECIES (SMALLEST GROUP)

NAMING OF ORGANISMS BINOMIAL NOMENCLATURE EX: Homo sapiens Pan troglodytes (chimpanzee) FIRST NAME IS GENUS NAME SECOND NAME IS SPECIES NAME

1) MONERA 2) PROTISTA 3) FUNGI 4) PLANTAE 5) ANIMALIA 5 KINGDOMS 1) MONERA 2) PROTISTA 3) FUNGI 4) PLANTAE 5) ANIMALIA

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