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H Bio Rossi - Everything you need to know about Ch. 15- Tracing Evolutionary History

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Big Bang Theory
- all the matter was in one big dump
- now billions of glalxies
early earth
- molten mass
- thick air
- water vapor condenses to form oceans as the earth cools
- lightning, volcanic eruptions, UV radiation
earliest proof of life on earth?
3.5 billion years ago
fossil (stromatolites)
stromatolites
collections of ancient photosynthetic prokaryotes
What is the earlier theory of life?
- the estimate is that life started 3.9 billion years ago
- however no evidence
- but had to be earlier bc stromatolites were already relatively complex
Louis Pasteur
all life arises only by the reproduction of existing life
4 Main Stages of Life arising:
1. Abiotic (nonliving) synthesis of small organic molecules --> nucleotide and amino acid
2. Formation of Polymers
3. Package molecules into "Protocells" --> proto prefix means last before fully something
4. Self- Replicating Molecules (inheritance)
Stanley Miller
- proved abiotic synthesis was possible
- showed how amino acids and other organics can be produced by the earth
Miller's Experiment
- recreated environment of early earth
- Results: the liquid contained H2O, hydrocarbons, amino acids, and other organic molecules
abiotic synthesis of polymers
- small organic molecules polymerize when they are concentrated on hot sand or clay
- the dilute solutions of amino acids on the hot sand act as minor enzymes to propel the synthesis of polymers
Protocells
-"prototypes of cells"
- isolation of a colletion of organic molecules with a membrane bound component
- vesicles should form when lipids are in H2O
- in conditions similar to 3.5-3.9 billion years ago, vesicles form faster
- once vesicles did form, they could divide
early RNA
short strands of self- replicating RNA molecules
riboenzymes
RNA molecule that acts as its own enzyme
macroevolution
a broad pattern of changes in life on earth
The distinct characteristic that marked the end of the Archaen Eon and the beginning of the Proterozoic Eon
O2 in the atomosphere
The distinct characteristic that marked the end of the Proterozoic Eon and teh beginning of the Phanerozoic Eon
animals
3 Mechanisms of Microevolution
1. Plate Tectonics
2. Continental Drift
3. Extinction
Plate tectonics
- last 1.5 billion years, 3 times all the land masses have come together and broken apart
- will happen again in 250 million years
Continental drift
-when tectonic plates move around like a puzzle and make new creations
- still occurs today and "proven" true by the location of fossils of modern ancestors
Extinction
could be due to climate change, biological community, habitat destroyed etc.
Mass extinction
- 50% of the organisms have to be killed off in order to be considered one
causes of mass extinctions
- volcanic eruption
- ice age
- O2 deficit
- Asteroid/Meteroid
Consequences of mass extinctions
- destroys thriving biological communitites
- removal of "the fittest" species
- 5-10 million years for diversity of life to return (however, can take longer)
Does evolution speed up or slow down after a mass extinction?
evolution speeds up after a mass extinction to fill in the "gaps" of the food chain
phylogeny
- the evolutionary history of a species or group of species
homologies
similarities due to shared ancestry
e.g. whale fin, bat wing, human hand
convergent evolution
species from different evolutionary branches may come to resemble one another
analogy
similarity due to convergent evolution
systematics
discipline of biology that focuses on classifying and determineng their evolutionary relatinships
Carlos Linnaeus
created taxonomy
taxonomy
system of naming and classifying speices
Binomial naming system
1. genus (capital first letter)
2. species (lowercase first letter
Biological classification system
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Phylogenic Trees
- depict how evolution connects a species
- similarities and differences
claudistics
- most common systematic method
- uses clades
- measure of shareable charcateristics
- usually indicate recent change
- most organisms on it are still alive
based on shared charcteristics of ancestors
clades
a group of species that includes an ancestor and all its descendancts
- clades are monophyletic
monophyletic
"single tribed"
shared ancestral character
what the modern ancestor had
shared derived character
a trait that the current organism has but the previous one didn't
Outgroup and Ingroup
Parismony
the adaptioin of the simplest explanation for oserved phenomenon
Systematics works via ...
Occam's Razor (a metaphor for shaving away the non- essential)
molecular systematics
- using DNA or other molecules to infer relatedness
- leads to the most correct trees
Molecular clock
- evolutionary timing method based on observations that at least some regions of genomes evolve at constant rates
use y =mx + b to solve
In the 1960s there were 5 kingdoms. What were they?
Animalia, Plantae, Protista, Fungi, Monera
3 Current Domains
Bacteria, Archaea, Eukarya
3 Theories to explain the relationship between the 3 current domains
1. Horizontal Gene Transfer
2. Origin Branch
3. Ring of Life
Horizontal Gene Transfer
- bacteria and archaea diverged early
- archaea and eukarya are closely related
See ch. 15 notes for diagram
Origin Branch
- same as horizontal gene transfer
See ch. 15 notes for diagram
Ring of Life
- eukaryotes arose through the fusion of bacteria and archaea
- eukarya is equally related to bacteria and archaea
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