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I. The Early Ideas
Spontaneous generation Nonliving material can produce life
Disprove Francesco Redi
Used maggots in covered and uncovered jars Louis Pasteur
Used curved flasks with heated broth
I. The Early Ideas
A. Francesco Redi 1668 Rotting meat kept
away from flies would not produce flies
Maggots only on meat exposed to flies Eggs laid on meat
I. The Early Ideas
B. Louis Pasteur Mid- 1800s Used curve-necked
flasks Microorganisms were
prevented from entering the flask
Curved necks broken, broth became cloudy with microorganims
I. The Early Ideas
Biogenesis All living things come from other living
things Louis Pasteur Completely disproved spontaneous
generation
II. The Modern Ideas
Alexander Oparin Life began in the oceans Energy from sun + lightning+ Earth’s heat =
simple compounds
Stanley Miller and Harold Urey
Used Oparin’s hypothesis to setup experiment
Conditions of early earth
II. The Modern Ideas
Water vapor, ammonia, methane, hydrogen
Sent electric current through Cooled gases, collected liquid Produced amino acids, sugars, and others
II. The Modern Ideas
III. Formation of Protocells Sidney Fox Produced protocells
Large, ordered structure, enclosed by a membrane
Carries out some life activities (growth and division)
Heated amino acids
IV. The First True Cells
Prokaryotes evolved from a protocell Heterotrophs (obtained food) Anaerobic
Archaebacteria Prokaryotic Autotrophs Deep-sea vents and hot springs
Photosynthesizing prokaryotes Increased oxygen in
atmosphere 2.8 bya
Eukaryotes evolved from prokaryotes Ozone provided protection
IV. The First True Cells
V. Endosymbiotic Theory
Bacteria (cyanobacteria) and chloroplasts resemble each other in size and photosynthesize
Chloroplast and mitochondria contain separate DNA, reproduce separately, have own ribosomes
V. Endosymbiotic Theory
In Conclusion: Aerobic prokaryotes evolved into
modern mitochondria
Photosynthetic cyanobacteria evolved into chloroplasts plant
Draw, Label, and Describe the Endosymbiotic Theory.
May use text book Pages 427-428
Endosymbiotic Theory
I. DarwinI. Darwin
Naturalist on HMS Beagle in 1831
collected, studied, stored biological specimens throughout South
America and South Pacific published “On the Origin of
Species by Natural Selection” in 1859
HMS Beagle
I. DarwinI. Darwin Traveled to Galapagos Islands Species of reptiles, insects, birds, flowering plants were
unique to the islands but similar to species elsewhere
I. DarwinI. Darwin Found that individuals struggled for existence
Competition for: Food Space Predators shelter
Food
Predators
Space
Shelter
Finding mates
I. DarwinI. DarwinArtificial Selection• Breeding organisms with specific traits in order to produce offspring with identical traits
DogsHorses
I. DarwinI. DarwinNatural Selection Mechanism for change in populations
Organisms with favorable variations for a particular environment survives, reproduce, and pass these variations on to the next generation
English moths
I. DarwinI. Darwin
Natural Selection Alfred Russel Wallace
Wrote similar ideas to Darwin Jointly presented Origin of Species written
II. Structural AdaptationsII. Structural Adaptations
A. Mimicry Enables one species to resemble another. Example: Bee orchid, yellow jackets
B. Camouflage Organisms blend with its surroundings Example: flounder
Praying mantis
Frog
Flounder
II. Structural Adaptations
III. Physiological Adaptations
Changes in an organism’s metabolic processes Direct evidence for evolution
Penicillin-resistance by some bacteria Pesticide-resistance by some insects
IV. Other EvidenceIV. Other Evidence
A. Fossils Provide a record of
early life and evolutionary history
Incomplete Found throughout
the world
IV. Other EvidenceIV. Other EvidenceB. Anatomy1. Homologous structures
Structural features with a common evolutionary origin Similar in structure, function or both Does not always mean that two species are related
2. Analogous structures Any part that is similar in function but different in structure Not used to indicate evolutionary relationship
• Birds and butterflies use wings to fly• Butterfly wings made of chitin• Bird wings made of bones
IV. Other Evidence
3. Vestigial structures Body structure in a present-day organisms that no
longer serves its original purpose Probably useful to ancestor Ex. Appendix in humans, pelvis and femur in whales
IV. Other Evidence
IV. Other EvidenceIV. Other EvidenceC. Embryology Embryo – earliest stage of growth and development of
plants and animals
Similarities in stages of embryonic development leading to distinct organism Ex. Frogs and humans
IV. Other EvidenceIV. Other EvidenceD. Biochemistry Use of DNA, RNA, ATP, and comparisons
Amino acid sequence of cytochrome c differ among different species
More reliable
More similarities – closely related
Indicates levels of relationships
Only populations evolve and not individual organisms Populations genes and frequencies change
over time Gene pool
The sum of all genes in a population Tells us that evolution occurs
I. Population Genetics
Genetic Equilibrium A population in which the frequency of alleles
remains the same over generations Genetic equilibrium = no evolution No equilibrium = evolution occurs
I. Population Genetics
Gene Flow Transport of genes by migrating individuals Immigration – individuals enter pop. genes
added to pool Emigration – individuals leave pop. genes are
lost from pool
I. Population Genetics
Mutation Results in useful variation
Genetic drift Alteration of allelic frequencies by chance events Affect small populations
Ex. Amish population
II. Changes in Equilibrium
A. Stabilizing selection Favors average individuals in a population
Ex. Plants - too short, not be able to compete for sunlight- too tall, susceptible to wind damage- select for medium height will increase
Ex. Woodpecker - selection for long beaks
B. Directional selection Favors one of the extreme variations of
a trait
Ex. Limpets- light and dark colored limpets are favored
C. Disruptive selection Favors either extreme of a trait’s variation
A group of organisms that have the ability to interbreed and produce fertile offspring
Species
Animal species
Plant species
A. Speciation Evolution of a new species Occurs when members of similar populations
no longer interbreed to produce fertile offspring within their natural environment
IV. Evolution of Species
B. Geographic Isolation Physical barrier divides a population
Droughts in forests, lava flows, sea level changes
IV. Evolution of Species
C. Reproductive Isolation Interbreeding organisms can no longer mate and
produce fertile offspring Ex. Tree frogs that mate in the summer cannot mate
with those that mate in the fall
IV. Evolution of Species
D. Change In Chromosome # Polyploids Species with a multiple of the normal set of
chromosomes Results from mistakes in mitosis or meiosis
IV. Evolution of Species
A. Gradualism Species originate through a gradual change of
adaptations
V. Rates of Speciation
B. Punctuated Equilibrium Speciation occurs relatively quickly, rapid bursts Niles Eldredge, Stephen J. Gould
V. Rates of Speciation
Adaptive Radiation When an ancestral species evolves into array
of species to fit a number of diverse habitats.
VI. Patterns of Evolution
Divergent Evolution Similar species become more and more
distinct Adaptation to different environmental
conditions
VI. Patterns of Evolution
Convergent Evolution Distantly related organisms evolve similar traits Unrelated species occupy similar environments in
different parts of the world
VI. Patterns of Evolution
Coevolution: evolution of two or more interdependent species,
each adapting to changes in the other Predator/prey Insects/flowers they pollinate
VI. Patterns of Evolution
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