6th_301M-Lecture

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First Exam Two Weeks from Today

Thursday 19 February

Covers Chapters 1-4, 6-7 plus Chapter 16 and first 9 lectures, 5 discussions, plus 8 Readings:

Scientific Methods

Natural Selection

Human Nature

Our Hunter-Gatherer Heritage

Evolution of Uncaring Humanoids

Solutions

Population Growth

Evolution

’ s Problem Gamblers

Big Bang 13.7-13.8 billion years ago

Life arose 3.5 billion years ago

Anaerobic versus aerobic bacteria, fermentation, respiration

Photosynthetic prokaryotes, origin of oxygen atmosphere

Endosymbiosis: origin of eukaryotes, plants, fungi, and animals

Reticulate Evolution: Mitochondria, Chloroplasts

Phylogenetic Systematics = cladistics, clades

Importance of shared derived characteristics (synapomorphies)

Monophyletic groups (Polyphyletic, Paraphyletic)

Sister groups, outgroups

Rooting phylogenetic trees

Infer/identify ancestral states — polarize character state changes

Hierarchical classification, Latin binomial nomenclature

Pongid (

Hominid

) phylogeny, blood group types

Organisms are classified hierarchically

5 Kingdoms: plants, animals, fungi, protists, bacteria

Phylum

Class

Order

Family

Genus

Species

Arthropoda

Insecta

Diptera

Drosophilidae

Drosophila melanogaster

Chordata

Mammalia

Primates

Hominidae

(Pongidae)

Homo sapiens

(the

sap

)

Mabuya Egernia

Eremiascincus

Ctenotus

N

A

Pongidae

Dance, Monkeys, Dance by Ernest Cline: http://www.youtube.com/watch?v=a15KgyXBX24

Pongid Phyogeny

Prosimian

Humans could have been stewards of Earth and all its many denizens, microbes, plants, fungi, and animals. We have the ability to have been God-like. Instead, for a short-sighted and selfish transient population boom, we became the Scourge of the planet. We wiped out and usurped vast tracts of natural habitat. We ate any other species that was edible and depleted all Earth

’ s multitude of natural resources. In a single century, humans burned fossil fuels that took millions of years to form.

Humans fouled the atmosphere, despoiled the land, and poisoned the waters, making the planet uninhabitable even to ourselves.

We trashed the life support systems of this, our one and only Spaceship, planet Earth.

The disparity between what humans could have been versus the pitiful creatures we actually managed to become is tragic and unforgivable.

If only more people would live up to their full potential!

Excerpts from Homer Smith (1952)

Man and His Gods

” and Lord Earl of Balfour (1895)

Foundations of Belief

Man did not have forever to harness the forces of the sun and stars. The

Sun was an elderly light, long past the turbulent heat of youth, and would some day join the senile class of once-luminiferous bodies. In some incredibly remote time a chance collision might blow it up again into incandescent gas and start a new local cosmic cycle, but of man there would be no trace. In Balfours's terms, he

“ will go down into the pit, and all his thoughts will perish. The uneasy consciousness, which in this obscure corner has for a brief space broken the contented silence of the universe, will be at rest.

Matter will know itself no longer.

Imperishable monuments

’ and

‘ immortal deeds,

’ death itself, and love stronger than death, will be as though they had never been. Nor will anything that IS be better or be worse for all that labour, genius, devotion and suffering of man have striven through countless generations to effect.

(Italics added)

Greenhouse Effect

Global warming

• CO

2 pollution of the air

– Burning oil, deforestation

Greenhouse gases cause warming •

Water vapor, H

2

O

Carbon dioxide, CO

2

Nitrous Oxide, N

2

O

N=N=O

• Methane, CH

4

= 25 molecules CO

2

• Trifluoromethyl Sulfur Pentaflouride, SF

5

CF

3

= 18,000 molecules CO

2

(half life = 1,000 years)

AVERAGE global temperatures are increasing.

– Ocean temperatures and acidity

– Sea levels rising

– Glaciers and ice caps melting

2013 396 ppm

Warming by Decade

James Hansen

Science

, 1431 (2005); 308

James Hansen,

et al.

2013 1824 ppb

2013 396 ppm

Milankovitch Cycles

Interglacials

2013 1824 ppb

2013 396 ppm

“The Long Summer”

°

C

°

C

°

C

°

C

°

C

H

|

Methane Clathrates and Hydrates

H— C — H + O

2

|

H

—> CO

2

+ H

2

O

H

|

H— C — H

|

H

H

|

H— C — H

|

H

An international consortium involving Canada, the US,

Japan, India, and Germany

Fracking for Natural Gas

H

|

H— C — H

|

H

Methane Emissions

Global warming may be slowing deep ocean currents

Milankovitch Cycles

Precession: At present, earth is closest to sun during winter in the northern hemisphere (11,000 years ago it was closest to the sun during summer in the northern hemisphere) (22,000 year cycle). Orbit itself shifts: Aphelion<——> Perihelion

Obliquity: Angle of inclination varies cyclically from

22

° to 24.5

° with a periodicity of about 41,000 years

(currently about 23.5

°

)

Eccentricity: Earth

’ s orbit changes from relatively circular to more elliptical and back again over a 95,000 year cycle.

Milutin

Milankovitch

Watch “TempFast.mov” 128 years go by in one minute!

1.74 times the area of Texas

Warming stresses ecosystems

• Coral reefs, tundra, Arctic

3.5 kilometers per year.

2030

The Big Apple finally goes under

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