theory of evolution chapter 15. charles darwin who was he? - english naturalist (studied and...
TRANSCRIPT
![Page 1: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/1.jpg)
Theory of EvolutionChapter 15
![Page 2: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/2.jpg)
Charles Darwin•Who was he?
- English naturalist (studied and collected
biological specimens)- sailed around the world on ship HMS
Beagle- known for his studies of the
Galapagos Islands- came up with idea of how organisms
change over time (natural selection)
![Page 3: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/3.jpg)
Natural Selection•A mechanism for change in populations.
•It happens when organisms with the best variations survive, reproduce, and pass their variations on to the next generation (population increases)
•Organisms that don’t have these variations are less likely to survive and reproduce (population decreases)
![Page 4: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/4.jpg)
How does Natural Selection Work
1. Organisms produce more offspring than can survive
2. Individuals have variations3. Individuals with certain useful
variations, such as speed, survive and pass on those variations
4. Over time, those individuals will make up most of the population
“Survival of the Fittest”
![Page 5: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/5.jpg)
Evidence for Evolution
Adaptations develop over many generations
1. Structural Adaptations:mimicry – when one species
resembles another species
camouflage – enables species to blend in
with their surroundings
![Page 6: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/6.jpg)
Mimicry
![Page 7: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/7.jpg)
Camouflage
![Page 8: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/8.jpg)
Camouflage
![Page 9: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/9.jpg)
Camouflage
![Page 10: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/10.jpg)
Canouflage
![Page 11: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/11.jpg)
Camouflage
![Page 12: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/12.jpg)
Camouflage
![Page 13: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/13.jpg)
Camouflage
![Page 14: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/14.jpg)
Camouflage
![Page 15: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/15.jpg)
Camouflage
![Page 16: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/16.jpg)
Natural Selection Example
1. Variation in Traits – some beetles are green and some are brown.
2. Green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do.
![Page 17: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/17.jpg)
3. The surviving brown beetles have brown baby beetles because this trait has a genetic basis.
4. The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown.
![Page 18: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/18.jpg)
2. Fossils3. Anatomy:
homologous structures – structures with
common evolutionary origins; can be similar
in arrangement, function, or both(ex. Forelimbs of whales, alligators,
birds)
analogous structures – body parts of
organisms that are similar in function, but
have no common evolutionary origin.(ex. Wings of birds, butterflies, and
bats)
![Page 19: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/19.jpg)
vestigial structures – structure that has
no function in a present-day organism, but
was probably useful to an ancestor
4. Embryology (embryos)- The embryos of a fish, reptile, bird,
and mammal are all similar in
appearance
5. Biochemistry- comparisons of DNA show
evolutionary relationships
![Page 20: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/20.jpg)
Homologous Structures
![Page 21: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/21.jpg)
Analogous Structures
![Page 22: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/22.jpg)
Population Genetics
•Can individuals evolve?
•Natural selection acts on the range of phenotypes in a population. (Strong genes get passed on to the next generation)
•Evolution occurs as a population’s genes and their frequencies change over time
![Page 23: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/23.jpg)
How Can A Populations Genes Change Over Time?
•All of the alleles of a population’s genes are known as the gene pool.
•The percentage of any specific allele in the gene pool is called the allelic frequency.
•A population is in genetic equilibrium if its alleles remain the same for generations.
![Page 24: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/24.jpg)
•A population that is in genetic equilibrium is not evolving.
•Anything that affects the genes in the gene pool can change allelic frequencies, disrupting a population’s genetic equilibrium, which would lead to evolution.
![Page 25: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/25.jpg)
Things that can affect genetic equilibrium:•Mutation•Genetic drift – the change of allelic
frequencies by chance events
(random)* greatly affects small populations
•Gene Flow – the movement of individuals in
and out of the population.•Natural Selection
![Page 26: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/26.jpg)
Natural Selection Acts on Variation•All traits have variation (look at everyone
in the class)
•Some variations increase or decrease an organism’s chance for survival in an environment.
•There are three types of natural selection that act on variation:
![Page 27: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/27.jpg)
1. Stabilizing Selection
•Favors average individuals
![Page 28: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/28.jpg)
2. Directional Selection
•Favors one extreme variation of a trait
![Page 29: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/29.jpg)
3. Disruptive Selection
•Favors both extreme variations
![Page 30: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/30.jpg)
The Evolution of Species
•How do changes in the gene pool result in the evolution of a new species?
•Species – a group of organisms that look alike
and can interbreed to produce fertile
offspring.
•Speciation – evolution of a new species
![Page 31: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/31.jpg)
Things That Cause Speciation:
•Geographic Isolation – happens when a physical barrier divides a population.
•Reproductive isolation – when formerly interbreeding organisms can no longer mate and produce fertile offspring.
![Page 32: Theory of Evolution Chapter 15. Charles Darwin Who was he? - English naturalist (studied and collected biological specimens) - sailed around the world](https://reader035.vdocuments.mx/reader035/viewer/2022062421/56649dcf5503460f94ac3beb/html5/thumbnails/32.jpg)
Patterns of Evolution
•Divergent Evolution – where species that once were similar become increasingly different.
*Adaptive Radiation – when a species evolves into a number of different species to fit a lot of different habitats.
•Convergent Evolution – where distantly related organisms evolve similar traits.