evolution
DESCRIPTION
Evolution. 3/27/12. Objective: Introduce origins theories Do Now: Hand in popular science questions Do Later: Read sections 13.1-3. Diversity of life. Estimated 10 million species on earth Phylogenetic trees show relationships. Origins Theories. Lamarck Spontaneous generation - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/1.jpg)
Evolution
![Page 2: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/2.jpg)
3/27/12
• Objective: Introduce origins theories
• Do Now: Hand in popular science questions
• Do Later: Read sections 13.1-3
![Page 3: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/3.jpg)
Diversity of life
• Estimated 10 million species on earth– Phylogenetic trees show relationships
![Page 4: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/4.jpg)
Origins Theories
• Lamarck– Spontaneous generation• Simple organisms are more recent• Complex organisms are older, gained complexity over
time
– Theory of Acquired Characteristics• Characteristics acquired by parents get
passed on to offspring
![Page 5: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/5.jpg)
Origins Theories
![Page 6: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/6.jpg)
Origins Theories
• Catastrophism– Rapid, catastrophic events shape
geology and extinction
• Gradualism– Slow change of geologic features
and life forms over time
Georges Cuvier
Charles Lyell
![Page 7: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/7.jpg)
Origins Theories
• “Descent with modification”– Species have natural variation– Certain characteristics are favored over time
![Page 8: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/8.jpg)
Natural Selection
• Condition 1: Variation– Populations must have variation in traits for
selection to occur
![Page 9: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/9.jpg)
Natural Selection
• Condition 2: Competition– “Survival of the fittest”• Scarce resources, avoiding predators, etc.
– Only the best adapted species survive
![Page 10: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/10.jpg)
Natural Selection
• Condition 3: Inheritance– Favorable traits are passed on to offspring– Genetic inheritance
![Page 11: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/11.jpg)
Natural Selection
• Theory of Natural Selection– Heritable traits that confer an advantage in
survival and reproduction will increase in frequency in a population.
– Gradually a population will change as a result of natural selection.
![Page 12: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/12.jpg)
Artificial Selection
• Selection performed by a conscious agent. – Dog breeding– Crop selection
![Page 13: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/13.jpg)
4/2/12
• Objective: To examine speciation and evidence for natural selection
• Do now: – Discuss with a partner – What is a species? – Come up with a definition in pairs
• Do later: Read 13.5-6 in text– On separate paper: Pg. 275 #1, 3-7, 12
![Page 14: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/14.jpg)
Species
• A species is a group of organisms that are able to interbreed and produce fertile offspring.
Mules are the offspring of a male donkey and a female
horse. They are sterile.
![Page 15: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/15.jpg)
Hybrid Species
Zebra + horse zebroid (sterile)
Tiglons can occasionally reproduce with difficulty.
![Page 16: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/16.jpg)
Speciation
• How do new species come to be (speciation)?– 1) Population is separated– 2) Each population changes due to natural
selection– 3) Differences accumulate to make interbreeding
impossible
![Page 17: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/17.jpg)
Evidence for Natural Selection
• Biogeography– Geographic distribution of species
Why do all marsupials live in Australia?
![Page 18: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/18.jpg)
Evidence for Natural Selection
• Homologous Structures– Anatomically similar structures in groups of
related organisms– May serve different functions
![Page 19: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/19.jpg)
Evidence for Natural Selection
• Molecular Biology– DNA sequencing can confirm the relationship
between two species• Few genetic differences = closely related• Many genetic differences = distantly related
98.5% similar
![Page 20: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/20.jpg)
4/3/12
• Objective:• Do Now: – Pick two evidences for evolution and explain (in
writing) how they show “descent with modification”. (3 minutes)
• Do Later:
![Page 21: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/21.jpg)
Evidence for Natural Selection
• Vestigial Structures– Structure that is no longer used in an organism– Artifact of a useful structure in an ancestor
![Page 22: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/22.jpg)
Vestigial Structures
• Whale pelvis
![Page 23: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/23.jpg)
Vestigial Structures
• Human Coccyx
![Page 24: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/24.jpg)
Vestigial Genes
• Vestigial genes – organisms have genes in their DNA that are no longer active
• Chicken teeth– Genes for teeth can be
turned back on in chickens
![Page 25: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/25.jpg)
Transitional forms
• Fossil evidence of an intermediate form between a present day species and an ancestor.
![Page 26: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/26.jpg)
Transitional Forms
• Archaeopteryx – transitional form between dinosaurs and modern birds
Archaeopteryx – between dinosaurs and aves (birds)
![Page 27: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/27.jpg)
Transitional forms
• Tiktaalik– Transitional form between aquatic and land
animals– “lobe finned fish”
![Page 28: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/28.jpg)
Transitional Forms
Basilosaurus – intermediate between land mammals and whales
whale
![Page 29: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/29.jpg)
Comparative Embryology
• Early stages of development are similar across the animal kingdom
![Page 30: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/30.jpg)
4/6
• Objective: To discuss pesticide and antibiotic resistance
• Do later: Popular Science – Pesticide and antibiotic resistance
![Page 31: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/31.jpg)
Pesticide Resistance
• Application of pesticides selects for pesticide resistance
Red = pesticide resistant
White = wild type (‘normal’)
![Page 32: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/32.jpg)
Pesticide Resistance
• Colorado Potato Beetle– Agricultural pest – Resistant to all major classes of insecticides
![Page 33: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/33.jpg)
Pesticide Resistance
• Can you think of any ways to combat pesticide resistance? – Pesticide rotation
– Natural predators
– Diversifying crops
The fungus Beauveria bassiana is toxic to many beetles but non-toxic to humans
Diversifying crops can limit the spread of pests
![Page 34: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/34.jpg)
Antibiotic Resistance
• Use of antibiotics selects for antibiotic resistant bacteria.
– Drug resistance evolves over time.
![Page 35: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/35.jpg)
Antibiotic Resistance
• Methicillin-Resistant Staph Aureus (MRSA)– “Staph infection”– Resistant to many classes of anti-staphylococcus
drugs
![Page 36: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/36.jpg)
Antibiotic Resistance
• Extensively Drug Resistant Tuberculosis (XDR-TB)– Lung disease
– Resistant to three or more major anti-TB drug classes
– High mortality (50% +)
![Page 37: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/37.jpg)
Antibiotic Resistance
• Solutions? – Limit prescription of antibiotics
– Limit use of antibiotics in agriculture
– Use full prescriptions
– Vary prescriptions
![Page 38: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/38.jpg)
4/17/12
• Objective: To examine varieties of selection
• Do Now: – With a partner, describe the differences between
natural selection, artificial selection, and sexual selection. Provide an example of each.
• Do later: – Read 13.13 and 13.17 in text
![Page 39: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/39.jpg)
Stabilizing Selection
• Selection that favors intermediate phenotypes
Stabilizing selection regulates birth weight
![Page 40: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/40.jpg)
Directional Selection
• Selection that favors extreme phenotypes in one direction
Peppered moths
![Page 41: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/41.jpg)
Disruptive Selection
• Selection that favors extreme phenotypes in both directions
Galapagos iguanas
![Page 42: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/42.jpg)
Practice time!
• With a partner, come up with an example of stabilizing and directional selection.
• Challenge: Can you think of an example of disruptive selection?
![Page 43: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/43.jpg)
Popular Misconceptions
• Natural Selection does not create any traits. – It only selects on existing traits.
Where do new traits come from?
![Page 44: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/44.jpg)
Popular Misconceptions
• Natural Selection is not goal oriented– Simpler organisms are older, but not less fit.
![Page 45: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/45.jpg)
Popular Misconceptions
• Natural Selection is subject to constraints– Advantageous traits often come with trade-offs
![Page 46: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/46.jpg)
4/20/12
• Objective: To learn about hypotheses for the origin of cells
• Do Now: In your notes, make a T chart to compare the conditions of early and modern Earth
• Do Later: Read Ch. 15.1-3 in text
![Page 47: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/47.jpg)
Early Earth Modern Earth
![Page 48: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/48.jpg)
Evidence for Early Life
• Stromatolites – 3.5 billion years old– Oldest fossils– Single celled organisms– Grow in mats that harden into rock
![Page 49: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/49.jpg)
Cell Theory
• Cell theory– All living things are composed
of cells and their products– New cells arise from the
division of older cells– Cells are the basic building
blocks of life
– Where did the first cells come from?
![Page 50: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/50.jpg)
Miller’s Experiment
• Stanley Miller (1953)– Hydrogen gas (H2)– Ammonia (NH3)– Methane (CH4)– Water vapor– Spark
• Product? Amino acids.
![Page 51: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/51.jpg)
Synthesis of Nucleic Acids
• Clay minerals catalyze the synthesis of DNA and RNA polymers
Montmorillonite
![Page 52: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/52.jpg)
Meteorite Delivery
• Murchison meteorite (1969)– Found in Victoria, Australia– Over 100 amino acids• L-amino acids
– Nitrogenous bases (DNA/RNA)
– Potential for extraterrestrial life
![Page 53: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/53.jpg)
Formation of Protocells
• Lipids in water spontaneously arrange into vesicles– Hydrophobic effects– Can also be catalyzed by clay
![Page 54: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/54.jpg)
Chicken-Egg Problem
• DNA is needed to make proteins, and proteins are needed to make DNA– Which came first?
![Page 55: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/55.jpg)
RNA World
• 1989 – Discovery of catalytic RNA– RNA has a sequence of bases like DNA– RNA can catalyze reactions like proteins
Ribosomes contain RNA to help catalyze protein synthesis
![Page 56: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/56.jpg)
Prokaryotic Life
• Oldest species on earth are prokaryotes– No membrane bound organelles
![Page 57: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/57.jpg)
Eukaryotic Life
• Eukaryotic cells have membrane bound organelles
![Page 58: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/58.jpg)
Mitochondria and Chloroplasts• Mitochondria and chloroplasts have unusual
properties– Double phospholipid membrane– Mitochondrial/Chloroplast DNA
![Page 59: Evolution](https://reader036.vdocuments.net/reader036/viewer/2022062520/5681610c550346895dd05c31/html5/thumbnails/59.jpg)
Endosymbiont Theory
• Primitive prokaryotes became eukaryotic organelles