1. Origin of Life

2. How would you define life?
Monday, March 9

3. Tuesday, March 10th
It is known that the continents once existed as one land mass known as Pangea. What is an explanation for the separation of this land mass into the continents we have today?

4. Wednesday, March 11th
What kind of evidence would you use to confirm humans relationships to mammals?

5. John Kyrk Evolution Timeline
As we scroll through the timeline write down interesting facts, questions, etc from each that we go through
Example: Hadean Era - Sun Ignites, Solar System Forms

6. The evolutionary tree of life can be documented with evidence.
Bacteria
Archae-
bacteria
Animalia
Fungi
Protista
Plantae
4500
4000
3500
3000
2500
2000
500
1500
1000
Formation of earth
Molten-hot surface of
earth becomes cooler
Oldest definite fossils
of prokaryotes
Appearance of oxygen
in atmosphere
of eukaryotes
First multicellular
organisms
Appearance of animals
and land plants
Colonization of land
by animals
Paleozoic
Mesozoic
Cenozoic
Millions of years ago
ARCHEAN
PRECAMBRIAN
PROTEROZOIC
The evolutionary tree of life can be documented with evidence.
The Origin of Life on Earth is another story…

7. What is Life? First we have to define LIFE… Organized as cells
Respond to stimuli
Regulate internal processes
Homeostasis
Use energy to grow
Metabolism
Develop
Change & mature within lifetime
Reproduce
Heredity
DNA / RNA
Adaptation & Evolution

8. The Origin of Life is Hypothesis
Special Creation
Was life created by a supernatural or divine force?
not testable
Extra-terrestrial Origin
Was the original source of organic (carbon) materials comets & meteorites striking early Earth?
testable
Spontaneous Abiotic Origin
Did life evolve spontaneously from inorganic molecules?

9. Conditions on Early Earth
Reducing atmosphere
water vapor (H2O), CO2, N2, NO2, H2, NH3, CH4, H2S
lots of available H & its electron
no free oxygen
Energy source
lightning, UV radiation, volcanic
low O2 = organic molecules do not breakdown as quickly
What’s missing from that atmosphere?

10. Origin of Organic Molecules
Water vapor
Condensed liquid with complex, organic
molecules
Condenser
Mixture of gases
("primitive
atmosphere")
Heated water
("ocean")
Electrodes discharge sparks
(lightning simulation)
Water
Abiotic synthesis
1920 Oparin & Haldane propose reducing atmosphere hypothesis
1953 Miller & Urey test hypothesis
formed organic compounds
amino acids
adenine

11. Stanley Miller Produced: amino acids hydrocarbons nitrogen bases
other organics

12. Key Events in the Origin of Life
Origin of Cells (Protobionts or “Protocells”)
lipid bubbles → separate inside from outside
→ metabolism & reproduction
Origin of Genetics
RNA is likely first genetic material
multiple functions: encodes information (self- replicating), enzyme, regulatory molecule, transport molecule (tRNA, mRNA)
makes inheritance possible
makes natural selection & evolution possible
Origin of Eukaryotes
endosymbiosis

13. Protocells A liposome is “giving birth” to a smaller liposome
Some liposomes could carry out metabolic reactions and export products (ie. phosphate and maltose) if the enzymes were carried through in the creation of new liposomes

15. Origin of Genetics RNA is likely first genetic material
multi-functional
codes information
self-replicating molecule
makes inheritance possible
natural selection & evolution
enzyme functions
ribozymes
replication
regulatory molecule
transport molecule
tRNA & mRNA

16. Timeline Key events in evolutionary history of life on Earth
3.5–4.0 bya: life originated
2.7 bya: free O2 = photosynthetic bacteria
2 bya: first eukaryotes

17. Prokaryotes O2 in the Atmosphere
Dominated life on Earth from 3.5–2.0 bya
O2 in the Atmosphere
Oxygen begins to accumulate 2.7 bya
reducing —> oxidizing atmosphere
evidence is banded iron in rocks = rusting
makes aerobic respiration possible
photosynthetic
algae

18. First Eukaryotes ~2 bya Development of internal membranes Prokaryotic
create internal micro-environments
advantage: specialization = increase efficiency
NATURAL SELECTION!
nuclear envelope
endoplasmic reticulum (ER)
nucleus
infolding of the plasma membrane
plasma
membrane
DNA
cell wall
plasma
membrane
Prokaryotic ancestor of eukaryotic cells
Prokaryotic
cell
Eukaryotic
cell

19. 1st Endosymbiosis Evolution of eukaryotes origin of mitochondria
engulfed aerobic bacteria, but did not digest them
mutually beneficial relationship
natural selection!
internal membrane system
aerobic bacterium
mitochondrion
Endosymbiosis
Ancestral
eukaryotic cell
Eukaryotic cell
with mitochondrion

20. 2nd Endosymbiosis Evolution of eukaryotes origin of chloroplasts
Eukaryotic
cell with
mitochondrion
Evolution of eukaryotes
origin of chloroplasts
engulfed photosynthetic bacteria, but did not digest them
mutually beneficial relationship
natural selection!
photosynthetic bacterium
photosynthetic bacterium
chloroplast
Endosymbiosis
mitochondrion
Eukaryotic cell with
chloroplast & mitochondrion

21. Theory of Endosymbiosis
Evidence
structural
mitochondria & chloroplasts resemble bacterial structure
genetic
mitochondria & chloroplasts have their own circular DNA, like bacteria
functional
mitochondria & chloroplasts move freely within the cell
mitochondria & chloroplasts reproduce independently from the cell

22. Cambrian Explosion Diversification of Animals
within 10–20 million years most of the major phyla of animals appear in fossil record
543 mya

23. Precambrian Era
Longest of the eras
Comprises about 87% of the geological timescale
Mass Extinctions
Episode of large-scale extinction in which large #’s of species disappear in a few million years of less
At least 5 major mass extinctions throughout history: Ordovician, Devonian, Permian, Triassic, and Cretaceous

24. Factors that Influence Evolution
Continental Drift: Movement of continents with respect to one another over the earths surface
Why do the continents drift? Plate Tectonics!
Plate Tectonics: Concept that the earths crust is divided into a # of fairly rigid plates

25. Where have we been?
Models of the origin of life
HWE and population genetics
Macroevolution/Speciation
What has driven the diversity and unity of life?
What is the end result of changes in populations (microevolution) over time?
How do times of ecological stress affect species diversity and the rate of speciation?

26. The process of evolution drives the diversity and
Big idea #1
The process of evolution drives the diversity and
unity of life.

27. Multiple Choice Answers
9. B
10. B
20. C
58. B