Download HB Unit 11 History of Life and Classification

History of Life and Classification
Unit 11: Chapter 14
Standards
• Compare principle of biogenesis with theory of
spontaneous generation
• Summarize Redi’s and Spallanzani’s experiments
• Explain the importance of RNA to the origin of life
• Relate photosynthesis to the development of aerobic
respiration
• Relate the concepts of adaptation and fitness to the
theory of natural selection
• Explain how anatomy and development provide
evidence of shared ancestry
• Compare artificial and natural selection
Biogenesis
• All living things come from other living things
Spontaneous Generation
• Living things arise from nonliving materials
Redi’s Experiment Disproved
Spontaneous Generation
Spallanzani’s Experiment Disproved
Spontaneous Generation of Microbes
Pasteur’s Experiment Established
Biogenesis as Cornerstone of Biology
Earth’s History
• Earth ≈ 5 billion years old.
• calculated by radiometric dating
-measure rate of radioactive decay of isotopes
-half life: amount of time ½ of an isotope
decays.
-carbon-14 is used to measure age of fossils.
Carbon-14
C-12: 6p and 6n.
Stable state
C-14: 6p and 8n.
Isotope, which must decay
to reach a stable state.
First Organic Compounds
• May have formed under high heat in
early atmosphere- Oparin
• Lightning, UV radiation may have energized
simple organic compounds to become
macromolecules- Miller, Urey
• Meteorites may have carried organic
compounds to Earth.
First Nucleic Acid
• First molecule of heredity may have been
RNA, not DNA.
-can assume more shapes than DNA.
-can catalyze reactions like a protein.
First Cells
• First cells may have been anaerobic, heterotrophic
prokaryotes
-no O₂ in early atmosphere.
-consumed spontaneously formed or organic
molecules.
• First autotrophic cells were chemosynthetic.
-energy from inorganic molecules, not light.
First Autotrophs
• were chemosynthetic.
-energy from inorganic molecules, not light.
• related to Archaea bacteria
-existed in harsh environments.
Photosynthesis and Aerobic
Respiration
• photosynthetic prokaryotes released O₂ into
atmosphere.
-cells resembled modern cyanobacteria.
-O₂ atoms were split in atmosphere to form
ozone.
First Eukaryotes
• larger than prokaryotes, have membranebound organelles.
• theory of endosymbiosis: prokaryotes were
engulfed by larger prokaryotes.
-mitochondria, chloroplasts
-evidence: independent replication; unique
DNA
Theory of Evolution
Unit 11: Chapter 15
Theory of Evolution
• Theory of Evolution: change in inherited
characteristics over time.
-new species develop from pre-existing ones.
• Charles Darwin:
-studied beak shape in Galapagos finches.
-published On the Origin of Species by Means
of Natural Selection.
Theory of Evolution
• change in inherited characteristics over time
due to environmental pressures.
-new species develop from pre-existing ones.
Contributing Scientists
• Cuvier- catastrophism: sudden geologic
catastrophes caused mass extinctions.
• Lyell- uniformitarianism: past processes that
changed Earth’s surface continue to be at
work.
• Lamarck- inheritance of acquired traits:
individuals could acquire traits by behavior;
traits could be passed on.
Charles Darwin
• Charles Darwin:
-naturalist.
-studied beak shape in Galapagos finches.
-published On the Origin of Species by Means
of Natural Selection.
-proposed that natural selection is the
mechanism for evolution.
Steps of Natural Selection
1. Overproduction: more offspring are produced than
survive.
2. Genetic variability exists in populations.
-mutations (random changes to DNA) are source of
variation; mutations within gametes are
inheritable.
3. Struggle to survive: environment favors survival
of individuals with adaptive trait.
4. Differential reproduction: adaptive trait leads to
more successful reproduction.
Survival of the Fittest
• Measure of genetic contribution to next
generation.
ex. Thick fur, speed, superb vision
Natural Selection and the Six
Kingdoms/Tree of Life
The Geologic Time Scale
Natural Selection & Genetic Resistance
• Ability of members of a population to resist a
chemical designed to kill it.
Evidence of Natural Selection
• Fossil record: entire
collection of preserved
species.
-represents ≈ 1% of all
species on Earth.
• Homologous structures:
-similar structures in
dissimilar species.
• DNA analysis
Limitations to Natural Selection
• Genetic change must precede change in the
environmental conditions.
• Reproductive capacity:
-species that reproduce rapidly and in large
numbers are better able to adapt.
Common Myths about Evolution
through Natural Selection
• “Survival of the fittest” is not “survival of the
strongest” .
(Fittest is in terms of leaving behind the most
offspring )
• Organisms do not develop traits out of need or
want.
• No grand plan of nature for perfect adaptation
(evolution is not “goal oriented).
Movement of the Earth’s Continents
over Millions of Years
Pangea’s breakup explained: Scrat’s Missing Adventure
Video Clip , Video Clip 2
Climate Change and Natural Selection
• Cyclical climate changes restrict location/
survival of populations.
-adapt, migrate or become extinct
4-4
Biodiversity, Speciation and
Extinction
• Biodiversity results from the interaction
between speciation and extinction.
Mass Extinctions
Cenozoic
Era
Period
Quaternary
Millions of
years ago
Today
Bar width represents relative
number of living species
Extinction
Tertiary
65
Extinction
Mesozoic
Current extinction crisis caused
by human activities. Many species
are expected to become extinct
within the next 50–100 years.
Cretaceous: up to 80% of ruling
reptiles (dinosaurs); many marine
species including many
foraminiferans and mollusks.
Cretaceous
Jurassic
Species and families
experiencing
mass extinction
Extinction
Triassic: 35% of animal families, including many
reptiles and marine mollusks.
250
Extinction
Permian: 90% of animal families, including over
95% of marine species; many trees, amphibians,
most bryozoans and brachiopods, all trilobites.
345
Extinction
180
Triassic
Permian
Paleozoic
Carboniferous
Devonian: 30% of animal families, including
agnathan and placoderm fishes and many
trilobites.
Devonian
Silurian
Ordovician
Cambrian
500
Extinction
Ordovician: 50% of animal families,
including many trilobites.
Fig. 4-12, p. 93
Speciation
Evolutionary process by which new biological
species arise:
• Geographic isolation: physical isolation of
populations for a long period lead to…
• Reproductive isolation: mutations in
geographically isolated populations prevent
the production of viable offspring.
Endangered Species
• Because of
scarcity of
inspectors,
probably no more
than 1/10th of the
illegal wildlife
trade in the U.S. is
discovered.
Figure 11-19