BIO 189

BIO 189

1. Evolution

   • Genetic Drift
     • random change in allele frequency
       • Examples
         • Bottleneck effect: population size is reduced for at least one generation
         • Founder Effect: when a individuals go and find a different population to colonize
     • big impact on small populations
   • 3 Modes of Selection
     • Stabilizing selection
       • better to be average
         • Ex. Population will move more toward being average
     • Directional selection
       • better to be one than the other
         • Ex. Humans would rather be more intelligent than less.
     • Disruptive selection
       • better to be one OR the other, but not average
         • EX. One can be male or female, but NOT both
   • Speciation
     • when two species separate and become part of two different populations over time
       • allopatic speciation
         • when many different mutation occur in the two populations due to speciation
       • sympatic speciation
         • not caused by geographical seperation
   • Reproductive Mechanisms
     • Extrinsic
       • Geographical serparation
         • species cannot breed if they are in different locations
     • Intrinsic
       • Ecological isolation
         • species cannot mate if they don't ever COME IN CONTACT
       • Temporal isolation
         • species cannot mate if they BREED at different times
       • Behavioral isolation
         • species cannot mate if NOT ATTRACTED to one another
       • Mechanical isolation
         • species cannot mate if NOT PHYSICALLY COMPATABLE
       • Gamete isolation
         • species cannot mate if EGG AND SPERM DO NOT FUSE PROPERLY
       • Hybrid Inviability or Infertility
         • even if fertilization is successful, that does not mean the offspring will survive, or reproduce.
   • Convergent evolution
     • when two species are unrelated but share similar features
       • EX. Horse and a Lipotherm (similar to a horse)
   • Abiogenisis
     • living organisms believed to have developed through nonliving ORGANIC molecules about 3.8 million years ago
     • Spontaneous Generation
       • unsupported notion that living organisms can arise spontaneously through COMPLEX non-living organisms
   • 4 Major ERAs
     • Oldest to Youngest
       • 1. Precambrian
         • photosynthesis, eukaryotics
       • 2. Paleozoic
         • mammals, reptiles, fish
       • 3. Mesozoic
         • dinosaurs
       • 4. Cenozoic
         • humans
       • separated by events
   • Viviparous
     • mammals that give birth to live young
   • Tetrapods
     • animals that have four limbs
   • Hominids
     • primates (who have opposable thumbs and that dwell on the ground
       • EX. Chinpanzeez, gorillas, orangutans, and humans
   • Protists
     • simplest eukaryotes
       • any organism that does not have all the necessary characteristics to be a plant, animal, or fungi
     • multicellularity first evolved
   • Coevolution
     • two or more species evolving together as result of their interaction
       • EX. Evolutionary Arms Race
         • Prey-predator, parasitic relationships lead to this
         • prey/host develop a mechanism that helps them avoid predators
     • Endosymbionts
       • mutualistic relationship
         • good example of coevolution
       • Gut Flora, Chloroplasts, mitochondria
   • Omnivores
     • eats both plants and animals
   • Detrivores
     • feed off dead or decaying organic matter
       • decomposers: break down organic matter into simple molecules
         • EX. Fungi & Bacteria

2. Urey-Miller Experiment

   • showed several organic compounds being formed spontaniously by simulating conditions of Earth's early atmosphere
     • it shows that it doesn't take much to make amino acids (building proteins)

3. Viruses

   • capsid
     • outer protection protein
   • contain genetic material (DNA, RNA) and several enzymes needed for replication
   • envelope contains receptor proteins that help the virus invade its target

4. Horizontal Gene transfer

   • Transduction
     • genetic material being passed on from one bacterium to another via bacteriophage
   • Conjugation
     • transfer of DNA from one bacterium to another
   • transfer of genetic material between peers
   • enables a rapid expression of benefitical genes for organisms
   • only for PROKARYOTES

5. Multicellularity

   • Colonial
     • all cells do the same thing
   • True
     • cells have different functions

6. Photosynthesis

   • Input: carbon dioxide + water
     • Output : sugar
     • 6CO2 + 6H20
   • Cellular Respiration
     • Input : carbohydrates + oxygen
       • Output: ATP
       • C6 H12 O6 + 6O2

7. Ecology

   • K selected species
     • R - selected species
       • limited by reproductive rate
       • short lived
       • produce MANY offspring, but take no care of them
     • equilibrium
     • larger, long lived
     • produce fewer offspring, take greater care for offspring
     • limited by carrying capacity
   • Ecological dominance
     • most numerous organisms in a community (usually plants)
   • Species Interactions
     • Competitive Exclusion
       • one species is better at getting the resource than the other
     • Resource Partitioning
       • when two species use the same resource to inhabit different parts of their shared habitat and coexist
     • Parasitism
       • where a species uses another species to its advantage and harms it in the process
     • Mutualistic/Symbolic relationship
       • both species benefit
     • Commensalistic
       • one organism benefits, the other is neither harmed nor helped
     • Amensalistic
       • one organism impedes/restricts other organisms without benefiting in the process

8. Carbon Cycle

   • 1. Photosynthesis
     • 2. Respiration
       • 3. Dead Organisms
         • 4. Fossil Fuels
           • 5. Burning of Fossil Fuels
   • only way C02 is removed from the atmosphere is by photosynthesis

9. Nitrogen Cycle

   • 1. Nitrogen Fixation
     • 2. Assimilation into plants
       • 3. Decomposition by bacteria and fungi
         • 4. Nitrifying bacteria
           • 5. Denitrifying bacteria