Larry M. Frolich, Ph.D. Biology Department, Yavapai College History and Evolution of Life Deep time evolutionary history Origin of Life Natural selection

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


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


•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)


Early Earth

• How do we know chemical make-up? From existing ancient rocks• Notice presence of molecules of life


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?


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


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?)


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


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



The Oxygen “Holocaust”


Evolution of eukaryotes



Multicellular life: development, life cycle, meiosis, fertilization, sex


Cambrian Explosion


Cambrian Explosion

http://pandasthumb.org/archives/Cambrian%20Explosion%20Marshall%2020061.html


Larry M. Frolich, Ph.D.Biology Department, Yavapai Collegehttp://palaeo.gly.bris.ac.uk/Essays/vertfr/default.html


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


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


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)


Homo floresiensis (12,000 years ago, Pacific Island)


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!


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?


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.


Development of agricultural systems were evolutionary events


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.


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


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?


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


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


Example 2: Guinea Pig—a triple domestication

Livestock

Lab animal

Pet


The Lungless Plethodontid Salamanders—pinnacle of evolution?

http://evolution.berkeley.edu/evosite/evohome.html http://autodax.net/feedingmovieindex.html

Documents

Larry M. Frolich, Ph.D. Biology Department, Yavapai College History and Evolution of Life Deep time evolutionary history Origin of Life Natural selection