1. There’s something you need to know…
The Origin of Species
Mom, Dad…
There’s something you need to know…
I’m a MAMMAL!

2. Speciation
__________________________________________________________________
Can be slow and gradual or in “bursts”
Extinction rates can be rapid and then adaptive radiation follows when new habitats are available

3. Correlation of speciation to food sources
Seed eaters
Flower eaters
Insect eaters
Rapid speciation: new species filling niches, because they inherited successful adaptations.
Adaptive radiation

4. So…what is a species?
Population whose members can interbreed & produce viable, fertile offspring
___________________________
Distinct species: songs & behaviors are different enough to prevent interbreeding
Humans re so diverse but considered one species, whereas these Meadowlarks look so similar but are considered different species.
Meadowlarks Similar body & colorations, but are distinct biological species because their songs & other behaviors are different enough to prevent interbreeding
Eastern Meadowlark
Western Meadowlark 4

5. How do new species originate?
When two populations become reproductively isolated from each other.
Speciation Modes:
___________
geographic separation
“other country”
_____________
still live in same area
“same country”

6. Allopatric Speciation
Physical/geographical separation of two populations
_______________________
After a length of time the two population are so different that they are considered different species
_________________________interbreeding will still not occur due to pre/post zygotic isolation

7. Sympatric Speciation
Formation of a new species without geographic isolation.
Causes:
____________ barriers exist to mating
_____________ (only organism with an even number of chromosomes are fertile…speciation occurs quickly)
Hybridization: two different forms of a species mate in common ground (hybrid zone) and produce offspring with greater genetic diversity than the parents….eventually the hybrid diverges from both sets of parents

8. Pre-zygotic Isolation
Sperm never gets a chance to meet egg
____________________: barriers prevent mating
Ecological isolation: different habitats in same region
_____________________: different populations are fertile at different times
Behavior Isolation: they don’t recognize each other or the mating rituals
________________: morphological differences
Gamete Isolation: Sperm and egg do not recognize each other
Sea urchins release sperm & eggs into surrounding waters where they fuse & form zygotes. Gametes of different species— red & purple —are unable to fuse.

9. Post Zygotic Isolation
______________– the embryo cannot develop inside the mothers womb
Hybrid Sterility – Adult individuals can be produced BUT they are not fertile
____________– each successive generation has less fertility than the parental generation
Species of salamander genus, Ensatina, may interbreed, but most hybrids do not complete development & those that do are frail.
Even if hybrids are vigorous they may be sterile; chromosomes of parents may differ in number or structure & meiosis in hybrids may fail to produce normal gametes Horse(64) x donkey(62) = mule (63 chromosomes)
In strains of cultivated rice, hybrids are vigorous but plants in next generation are small & sterile.
On path to separate species.

10. Evolutionary Time Scale
_______________ – changing of allele frequencies in a population over time.
______________ – patterns of change over geologic time. Determines phylogeny
Gradualism – ______________________
Punctuated equilibrium – periods of massive evolution followed by periods with little to no evolution

11. What must Earth have been like before living things took over?
Origin of the Earth
What must Earth have been like before living things took over?

12. The Primitive Earth Atmosphere:
All chemicals/compounds necessary are thought to have originated on earth
Inorganic precursors:
Water vapor
Nitrogen
Carbon dioxide
Small amounts of hydrogen and carbon monoxide
These were the monomers for forming more complex molecules.
Experiments have shown that it is possible to form organic from inorganic.

13. Key Events in Origin of Life
Origin of Cells (Protobionts)
lipid bubbles  separate inside from outside
 metabolism & reproduction
Origin of Genetics
__________________________
multiple functions: encodes information (self-replicating), enzyme, regulatory molecule, transport molecule (tRNA, mRNA)
makes inheritance possible
______________________
Origin of Eukaryotes
endosymbiosis
Life is defined partly by two properties: accurate replication and metabolism. Neither property can exist without the other. Self–replicating molecules and a metabolism–like source of the building blocks must have appeared together. How did that happen?
The necessary conditions for life may have been met by protobionts, aggregates of abiotically produced molecules surrounded by a membrane or membrane–like structure. Protobionts exhibit some of the properties associated with life, including simple reproduction and metabolism, as well as the maintenance of an internal chemical environment different from that of their surroundings.
Laboratory experiments demonstrate that protobionts could have formed spontaneously from abiotically produced organic compounds. For example, small membrane–bounded droplets called liposomes can form when lipids or other organic molecules are added to water.

14. Prokaryotic ancestor of eukaryotic cells
First Eukaryotes
~2 bya
Development of internal membranes
create internal micro-environments
_________________________________
natural selection!
nuclear envelope
endoplasmic reticulum (ER)
plasma
membrane
infolding of the plasma membrane
nucleus
DNA
cell wall
plasma
membrane
Prokaryotic
cell
Prokaryotic ancestor of eukaryotic cells
Eukaryotic
cell

15. internal membrane system
1st Endosymbiosis
Evolution of eukaryotes
___________________
____________________, but did not digest them
mutually beneficial relationship
natural selection!
internal membrane system
aerobic bacterium
mitochondrion
Endosymbiosis
Ancestral
eukaryotic cell
Eukaryotic cell
with mitochondrion

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

17. Theory of Endosymbiosis
Evidence
structural
mitochondria & chloroplasts resemble bacterial structure
genetic
______________________________________________________________________________________
functional
mitochondria & chloroplasts move freely within the cell
mitochondria & chloroplasts reproduce independently from the cell

18. Evidence Supporting Evolution
2006 Fossil Discovery of Early Tetrapod
“Tiktaalik”
“missing link” from sea to land animals
Evidence Supporting Evolution

19. Evidence for Evolution
Paleontology – fossils show change in a species over time
Biogeography – Similar species are found in similar ecosystems around the world
Morphology – Comparing structures
__________________– body parts with similar structure but possible different function. Shows common ancestry
Analogous structures – similar structure develops in organisms that share a common ecosystem but not a common ancestry
Biochemical or Molecular -
__________________________________

20. Fossils Preserved remains of living things
Paleontology is the study of the fossil record
Most organisms do not leave a fossil after death
Explains the “missing links”
Sedimentation Fossils
As the organism decomposes the spaces will be filled with the minerals from the silt

21. Fossil Evidence of Evolution
Fossils are the preserved remains of once-living organisms
Rock fossils are created when three events occur
_______________________
calcium in bone or other hard tissue mineralizes
surrounding sediment hardens to form rock

22. How old is that fossil? Relative Dating _______________
____________________________________________
_______________
Age of fossils determined by analyzing the content of radioactive isotopes found in the fossil.
Half-life: The length of time required for half of the radioactive elements to change into another stable element.
Unaffected by temperature, light, pressure, etc.
All radioactive isotopes have a dependable half life. Ex: C14 decays into N14

23. Patterns of Evolution Divergent Evolution (adaptive radiation)
_________________
Is it a shark or a dolphin??

24. Divergent vs. Convergent
Types of EVOLUTION
Divergent vs. Convergent

25. DIVERGENT EVOLUTION
__________________________. Think of other words that use the same root word. “Dissect, Divide, Divorce”
Could two or more different species have shared a common parental species?

26. ADAPTIVE RADIATION
- In some circumstances, many separate groups will break off from the main population to form their own isolated gene pools. These individual gene pools will undergo their own changes due to Genetic Drift, Mutation and Natural Selection. During these circumstances, many new species may form from one Parental Species. This is known as ADAPTIVE RADIATION

27. CONVERGENT EVOLUTION
__________________________. Think of other words that use the same root word.
“Congregate, Concert, Connect”
Could two or more different species that look similar and have similar traits, be totally unrelated
To one another?

28. Anatomical Evidence for Evolution
Homologous structures: structures with different appearances and functions that all derived from the same body part in a common ancestor
The bones in the forelimb of mammals are homologous structures
__________________________________

29. Anatomical Evidence for Evolution
Analogous structures: ___________________________________________________________________
Same functions, different ancestor structure

30. Anatomical Evidence for Evolution
Vestigial structures: __________________________, but resemble structures their ancestors possessed
Vestigial structures of a whale

31. Coevolution _______________________________________________________
predator-prey
disease & host
competitive species
mutualism
pollinators & flowers