Evolution by Natural Selection
www.biblewheel.com/ History/C19_Evolution.asp
ES 100: Environmental Ecology
10/2/06
Roots of Ecology
• Relatively new science
• Carl von Linné (mid 1700’s)
• classification of living things
The Classification of Living Things
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primata
Family: Hominidae
Genus: Homo
Species: Sapiens
Roots of Ecology
• Carl von Linné (mid 1700’s)
• classification of living things
• Alexander von Humboldt (early 1800’s)
• botanical geography
• Charles Darwin and Alfred Wallace 1850
• animal geography
• theory of evolution by natural selection
• Ernst Haeckel 1866
• coined the term “ecology”
• Edward Suess 1875
• “biosphere” as the condition that promotes life: it includes plants, animals,
and non-living things
• Arthur Tansley 1935
• “ecosystem” concept: interaction between living and non-living entities in
the biosphere
Hypotheses, Theories and Your Textbook
http://home.comcast.net/~fsteiger/cartoon2.gif
Theory of Evolution by Natural Selection
• Natural selection is the mechanism that explains evolution
• Natural Selection: scale = individual
• Evolution: scale = many generations
Temporal Scale
Animation of whale evolution: Click here
Theory of Evolution by Natural Selection
• Natural selection is the mechanism that explains evolution
• Natural Selection: scale = individual
• Evolution: scale = many generations
• Darwin’s observations:
• Organisms produce more young than can survive.
• All species exhibit genetic variability (from mutation and
random combination of parent’s genes).
• Individuals with traits most suited to environment most
likely to survive.
• Only survivors contribute to the gene pool.
• Theory: Lineages with most appropriate biological
programming (genes) for current environmental conditions will
leave the most descendants.
Bush, page 7:
“Sickle-cell anemia, Down’s syndrome, and
color blindness are heritable, and each
would reduce an individual’s chance of
survival in a wild human population”
When is Mutant Sickle-cell Gene
Desirable?
www.sicklecelldisease-il.org/.../ what/how.html
Natural Selection and Physical
Appearance
Optimal Foraging Theory
• Organisms that ‘forage’ most efficiently will be
more likely to reproduce (improve fitness)
– Thus, natural selection favors optimal foraging.
– Cost/benefit analysis
• What is foraging?
police.ucsb.edu/ crime_prevent.html
• What do plants and animals forage for?
SWEATY T-SHIRT EXPERIMENT:
http://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html
Natural Selection and
Biochemical Traits
Testing Hypotheses:
Observation vs. Experimentation
• Observation:
• See patterns in the field
• Strength:
grounded in reality
• Weakness:
mechanistically weak
• Experimentation:
Manipulate system by
creating experiments
• Strength: control
variables
• Weakness: not realistic
Natural Selection and Behavior
Is Human-Environmental Behavior a
Result of Natural Selection?
•
•
•
•
Genetically Based Reproductive Urges?
Short-term Egoists?
Altruism- inclusive fitness?
Reciprocal Altruism?
• What are the implications for environmental
management?
Are Human’s Exempt from
Natural Selection?
Defining ‘evolution’
Scientific Definitions:
• All the changes that have transformed life on earth from its
earliest beginnings to the diversity that characterizes it today
–Neil Campbell
• The origination of species of animals and plants
–O.E.D.
…
Common Usage:
• A process of continuous change from a lower, simpler, or worse
to a higher, more complex, or better state
–Merriam-Webster’s Dictionary
From a scientific point of view, evolution is just how new
species come about
Humans as an Evolutionary Endpoint?
Theory of Evolution: Criticisms
• Microevolution is generally accepted, but
macroevolution is hotly debated
– How does evolution add information to a genome to
create progressively more complicated organisms?
– How is evolution able to bring about drastic changes so
quickly?
– How could the first living cell arise spontaneously to
get evolution started?
Pakicetus
Ambulocetus
Basilosaurus
Humpback
Section this Week
Internet assignment for section this week:
–
–
–
–
Visit course website
Follow “Feast of the Biomes” link
Prepare (typed) assignment and bring to section
Bring food to section (can bring a form of the
fruit/vegetable- chocolate instead of cocoa beans)