Larry M. Frolich, Ph.D. Biology Department, Yavapai College History and Evolution of Life Deep time...
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Transcript of Larry M. Frolich, Ph.D. Biology Department, Yavapai College History and Evolution of Life Deep time...
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
History and Evolution of Life• Deep time evolutionary history• Origin of Life• Natural selection• Major Events and Extinctions• Human Evolution• Domestication of Species
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
What is deep time?
• To understand evolution, we must appreciate deep time (like deep space)—time stretching beyond what is easy to intuitively grasp
• Outstretched arms all of Earth’s four billion year history—one swipe of a finger-nail file and human history is gone)
• Toilet paper analogy—if a roll of toilet paper is Earth history, humans reside in the shreds at the end of the very last sheet.
• See weblinks for more views of Earth history and deep time
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
•Let a roll of toilet paper represent the four billion (4.0 B) year history of life on Earth •If the roll has 1000 sheets (Scott brand), then each sheet represents four million (4.0 M) years •If the roll has about 200 sheets (more typical smaller rolls), then each sheet represents 20 million (20.0 M) years •Here are some key events:
EVENT TIME BEFORE PRESENT(BYA--billions of years ago(MYA--millions of years ago)
SHEET NUMBER ON THE TYPICAL ROLL
Formation and Solidification of Earth 4.6-4.0 BYA 1
Oldest Rocks Known 3.8 BYA 10
Earliest evidence of life--carbon forms in rock 3.8 BYA 10
Earliest fossil prokaryotic cells 3.5 BYA 25
Oxygen levels rise steeply due to increase in photosynthetic activity
2.5 BYA 75
Complex eukaryotic cells appear in fossil record 1.5 BYA 125
First multicellular organisms in fossil record 600 MYA 170
Burgess Shale--exposion of multicellular diversity--most multicellular animal groups represented in primitive form
515 MYA 176
First land vertebrates 350 MYA 183
Archaeopteryx--precursor to birds (and other dinosaurs) 150 MYA 192
End Cretaceous Extinction--goodbye dinos, hello mammalian, bird, flowering plant diversity
65 MYA 196
Lucy--Australopithecus 4 MYA 1 (last 1/4 of sheet)
Homo erectus, fire 1 MYA 1 (last 1/20 of sheet)
Start of agriculture, settlements 10,000-20,000 years ago 1 (last fibers)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Early Earth
• How do we know chemical make-up? From existing ancient rocks• Notice presence of molecules of life
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Stanley Miller experiments• Early Earth
atmosphere• Energy
applied• Organic
molecules including all molecules of life and “micelles” formed
• Today—fully engineered life—how far off?
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Evidence for historical fact of evolution• Fossil record
– Most rocks contain fossils
– Long-term change in biological communities
– Transitions: origin of mammals, origin of birds
• Anatomical similarities
• Shared embryological features
• Shared biochemical and genetic features
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
How does evolution happen?• Darwin’s great idea—natural
selection• Just like “artificial selection” for
agricultural breeds (in fact, is there any difference—what is “artificial” about human involvement?)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Major Events in the History of Life• Prokaryotes• Photosynthesis• Eukaryotes• Multicelled animals—development and life cycles• The Cambrian Explosion—inverts, fishes• The End Permian Mega-Extinction• Onto land—land vertebrates• Amphibians mammals and everything else• Dinosaurs• End Cretaceous Extinction• Birds, bees, butterflies, flowers…and mammals• Humans• Salamanders
Larry M. Frolich, Ph.D.Biology Department, Yavapai Collegehttp://www.physicalgeography.net/fundamentals/9a.html
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Prokaryote Evolution
http://web.uconn.edu/gogarten/progenote/progenote.htm
Larry M. Frolich, Ph.D.Biology Department, Yavapai Collegehttp://www.steve.gb.com/science/photosynthesis.html
Evolution of Photosynthesis
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
The Oxygen “Holocaust”
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Evolution of eukaryotes
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Multicellular life: development, life cycle, meiosis, fertilization, sex
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Cambrian Explosion
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Cambrian Explosion
http://pandasthumb.org/archives/Cambrian%20Explosion%20Marshall%2020061.html
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai Collegehttp://palaeo.gly.bris.ac.uk/Essays/vertfr/default.html
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Humans are primates
• Our closest living relatives are monkeys and apes
• We share a common ancestor, most recently with apes, farther into deep time with monkeys and even farther in with lemurs and tarsurs
• The living species are not our actual ancestors—we need the fossil record to see them
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Fossil record of primates evolutionarily close to humans
• Mediocre human fossil record• Not all fossils on direct ancestral line to humans• Past shows many different human and human-like species living at one time
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Accident of history—one human species today• Good solid evidence that living
humans form one single species—Homo sapiens– Ability to interbreed– Little anatomical difference among
populations– Little biochemical difference
among populations– DNA and protein analysis show
recent single common ancestor within 1 million years, perhaps only 200,000 years ago
• But past was different (evolution is not planned!)– H. neanderthalis (200,000 years
ago)– H. floresiensis (12,000 years ago)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Homo floresiensis (12,000 years ago, Pacific Island)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Comparison Neanderthal and Modern human skulls
Good evidence that Neanderthals buried dead, had religion, cultural practices, used tools
Imagine a world where another sentient, culturally-driven primate lived!
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Humans today
• Dominate planet
• Ecologists have often focused on “wild” ecosystems
• But most landscapes now have some human elements, usually very strong effects
• Is this good or bad? And for whom?
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Relationships among species• In a community, relationships among species can be
beneficial, damaging or neutral:– Symbiotic: mutually beneficial, both species benefit– Parasitic: one species benefits (“parasite”) and the other is harmed
(“host”)– Commensal: One species benefits, the other is unharmed– Mutualism: both species benefit, like symbiosis, but it may appear one
species has the advantage, but evolutionarily, over the long-term, both benefit
– Predation: Usually considered parasitic, where the predator is the parasite, but can also be seen as mutualistic
• We think of species in a community as “co-evolving” to establish these types of relationships
• For some reason, we don’t tend to analyze human relationships with other species this way. But domestication of other species, originally for agriculture, is most often mutualistic.
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Development of agricultural systems were evolutionary events
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
What is domestication? What is food? How did it all come about?
• We tend to assume that we are “consuming” resources—physical or biotic. This is the view your text mostly provides
• But another way of thinking is that those species who co-evolved with us into domestication have also been “winning” the evolutionary game, or multiplying their numbers with us (more dogs or wolves?; more horses or zebras?; more corn or teosinthe?). Who “domesticates” whom? Who started the relationship? Was it the plant who made its seed obvious and easy to cultivate, or the humans who “discovered” that seed? Was it the animal breed that was naturally social and docile, or the humans who tamed the animal?
• We can even understand laboratory domestications (salamanders for developmental studies; E. coli for recombinant DNA studies and production; white mice as human analogs) as the most recent way in which other species have convinced us to take care of them.
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Our relationship with domesticated species• We do still have ecological relationships with “wild” species.
Examples:– Hunt mushrooms– Create game reserves– Create national parks – household and urban/rural “pests” (e.g. molds, sewer rats)– Symbiotic micro-organisms (skin and mouth bacteria)– Disease-causing micro-organisms
• But mostly we have tight relationships with domesticated species. Basis for ecological relationship:– Food and agriculture (by far most common—food crops and animals)– Transportation (“beasts of burden”)– Care and protection (pets)– Laboratory study and production– Other?
"It makes just as much sense to think of agriculture as something the grasses did to people as a way to conquer the trees."--Michael Pollan, 2001, The Botany of Desire
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Resource use, or evolution of the domesticate relationship?
• Our quality of life depends on how these domesticate relationships continue to evolve.
• For the Earth, or the eco-systems, this evolution will just be something “natural.”
• For us, it will determine how much suffering versus how much plenitude people will experience
• Over deep time history, large animals, and especially large mammals like ourselves, have been prone to raid extinction
• Will our sentient nature overcome this trend?
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Domestication (or Human co-Evolution) Today
• Early agricultural domestication was with species that– Behave well with humans– Make their reproductive processes obvious to humans
• But what are domestications of last 100 years– Laboratory domestications– Species that can survive indoors– Species that make some aspect of their biology—
usually at cellular/developmental/molecular level—easily accessible to humans
FLT
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Example 1: E. coli
WHY HUMANS “LIKE” E. coli• Adaptable and reproduces
under wide variety of lab conditions
• Easy visualization• Genes and proteins easily
accessible• Endonucleases and other
DNA manipulation genes/proteins known and isolated
WHY E. coli “LIKES” HUMANS• Provide new and safe
environments for reproduction• Make new genetic material
accessible• Virulent strains with easy human
access“Unintended” consequence of E. coli domestication—virulent,
anti-biotic resistant strains
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Example 2: Guinea Pig—a triple domestication
Livestock
Lab animal
Pet
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
The Lungless Plethodontid Salamanders—pinnacle of evolution?
http://evolution.berkeley.edu/evosite/evohome.html http://autodax.net/feedingmovieindex.html