“change over time” how did the giraffe get its long neck? before darwin….. lamark stated that...
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“Change over time”
How did the giraffe get its long neck?
Before Darwin….. Lamark stated that organisms evolve
Lamarck was rejected because his mechanism by which evolution occurred was not supported by DATA
Lamark’s ideas: evolution was driven by an inner “need”
acquired characteristics could be passed to the next generation
More offspring are produced that can possibly survive.
BUT populations tend to remain stable
AND there are limited resources
Observation #1
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
Organisms display a lot of variety in their characteristics
Much of this variety is inherited
OBSERVATION #2
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
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
Fossils provide evidence of the change of life throughout time
Comparative Anatomy
Homologous structures: indicators of a common ancestor
Anatomical
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 structuresEvolved independently and don’t indicate close relationships
A) Divergent evolution results in homologous structures
B) Convergent evolution results in analogous structures
Generation to generation change in the frequencies of alleles in the
gene pool
Genetic Drift: changes in allele frequencies due to chance
Causes:natural selection
Gene flow immigration or emigration of individuals (and their genes)Mutation introduces new alleles
Example #2Relatively few individuals start a new population in isolation
founder effect
Examples of Genetic DriftNatural disaster wipes out a portion of a population
= original population
= population after introduction of peccaries
Peccaries are great predators of cacti
Peccaries are great predators of cacti
Parasitic wasps lay eggs at the base of the spines. Hatched larva feed on the cactus
Peppered moth Clutch size in birds “Jacks” (small 2 yr.old sexually mature male salmon) and Hooknoses” (large 3yr old sexually mature male salmon) the smallest jacks and largest hooknoses are most successful breeders Human birth weights Insecticide resistance
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
Fig. 14-3e
Postzygotic BarriersHybrids do not develop into
fertile adults
National Geographichttp://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
Mediumground finch
Cactusground finch
Smalltree finch
Largeground finch
Smallground finch
Large cactusground finch
Sharp-beakedground finch
Vegetarianfinch
Seedeaters
Ground finches
Cactus flowereaters
Budeaters
Tree finches
Insecteaters
Mediumtree finch
Largetree finch
Mangrovefinch
Woodpeckerfinch
Greenwarbler finch
Warbler finches
Which finch is most closely related t the Green warbler finch?
Is the medium ground finch more closely related to the small ground finch or to the large ground finch?
• Beastie Activity
Figure 15.12A
Pleistocene
Pliocene
Mio
ce
ne
Oli
go
ce
ne
Brown bearPolarbear
Asiaticblack bear
Americanblack bear
Sunbear
Slothbear
Spectacledbear
Giantpanda
RaccoonLesserpanda
Ursidae
Procyonidae
Common ancestralcarnivorans
• For several decades, scientists have classified life into five kingdoms
THE DOMAINS OF LIFE
Figure 15.14A
MONERA PROTISTA PLANTAE FUNGI ANIMALIA
Earliestorganisms
• 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
Figure 15.14B
BACTERIA ARCHAEA EUKARYA
Earliestorganisms
• 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 NOMENCLATUREEX: Homo sapiens
Pan troglodytes (chimpanzee)
FIRST NAME IS GENUS NAMESECOND NAME IS SPECIES NAME
5 KINGDOMS
1) MONERA
2) PROTISTA
3) FUNGI
4) PLANTAE
5) ANIMALIA
http://www.cliffsnotes.com/WileyCDA/CliffsReviewTopic/Classification-Plants-Other-Organisms.topicArticleId-23791,articleId-23659.html