Natural selection

Campbell and Reece, Chapter 22 (but lecture goes way beyond chapter)

As an extension of the idea of "natural selection", we should consider selection after human influences:
DDT resistance
antibiotic resistance-STD and in agriculture
even antiviral drug resistance now that there are antiviral drugs that are used


(MANY) - 1.6 million known - maybe several million more
maybe 100 x as many in the past
mass extinctions, most past species gone

One species definition: Reproduce, fertile offspring
Hereford Brahman (same species) SLIDE
Tiger - lion: (different species) Tigon, SLIDE
Horse - donkey (differenty species): Mule, SLIDE (here is my friend's late dad proudly posing with his Missouri mules)
there are many limitations to this theory (especially it only applies to sexually reproducing species)


Natural selection, selection pressure, survival of the fittest, adaptation for survival, adaptive radiation.
Survival = Reproduce
Ultimately, survival is not of the individual but of genes.

vestigial structures - human appendix, male nipples
comparative anatomy and embryology
Convergent evolution -wing of insects and birds

Natural selection, SURVIVAL (to reproduce)
of THE FITTEST (English peppered moth example) SLIDE
camouflage - cryptic coloration

Warning coloration (opposite strategy of crytic coloration)
SLIDE poisonous snake
Mimicry - viceroy SLIDE
Monarch, milk weed, digitalis 1 trial learning SLIDE

Altruism - parental, survival of genes (birds) etc
SLIDE - poison arrow frog
wolf spiders
Honeybees Queen, workers, drone (SLIDE)

Sexual selection - SLIDE think of survival of fittest
(cheetah and Thomson's gazelle Serengeti)
- Peacock SLIDE

Praying mantis SLIDES


Lamarck (1744-1829) use and disuse. Giraffe example

Darwin (1809 - 1882) survival of the fittest
(1) survival means to reproduce
(2) fittest may have as much to do with likelihood of reproducing as toughness

Voyage of HMS Beagle 1831 - 1836 Book 1839
Galapagos - "tortoises" - Darwin was impressed with DIVERSITY (not so much in England)
"Darwin's finches" - TRANSPARENCY - (an interesting diagram from another book)
also TRANSPARENCY (Fig. 1.17) [so fundamental that the authors moved it to Chapter 1!)
Darwin's finches
(Islands are particularly interesting. For instance birds on islands w/o predators like dodo, have relaxed selection pressure until environment changes - humans with clubs arrive.)
volcanic, 600 mi from Ecuador, 1 million yrs (young)
13 species diversity
woodpecker finch - twig to get insects (tongue short)
(could not compete)
The idea is that the ancestor colonized these islands recently (relative to the geological time scale), and there has been divergent evolution to make different species that have different adaptations for survival in terms of feeding (like type of beak) or where they nest. With reference to "ecology" lectures second semester, there are niches that eventually get filled.

Influences on Darwin:
Malthus Essay on the Principle of Population 1798 (philosopher of gloom - population will grow exponentially, and resources will at best increase linearly so that eventually there will be a struggle for survival.
Lyell geology, earth changes slowly
Origin of species 1859 Alfred Wallace 1858

Voyage of HMS Beagle - Controversy, skipper Fitzroy commit suicide
Thomas Huxley (Huxleys) (vs. Bishop Samuel Wilberforce 1860)
British Asdsociation for the Advancement of Science
"would have rather descended from an ape than from a cultivateed man who prostituted the gifts of culture and eloquence to the service of predjudice and falsehood"

Scopes (John) "monkey trial" Dayton Tenn. 1925
Clarrence Darrow
William Jennings Bryant silver-tongued orator, former Pres candidate, died after
Curtis of UMC was a witness
found guilty and fined $100
Play: Jerome Lawrence and Robert E. Lee published their dramatized account of the trial in Inherit the Wind.

Creationism - TRANSPARENCY from an early 1960's paper by George Wald on the Origin of life
TRANSPARENCY Bible - note how short the story of creation is
Fundamentalism,equal time in text book controversies,


In addition to divergent evolution, there is convergent evolution (like insects and birds both have wings but not derived from a primordial anatomical structure in a common ancester) and coevolution, the latter being a topic at the interface between evolution and ecology (Chapters toward the end of the book)

Symbiosis (living together)
Parasitism & Mutualism (for mutual benefit)
Bacteria in gut, E.coli, superinfection after
broad-spectrum antibiotic
Nitrogen fixation
Microorganisms in termite gut - cellulose
Lichens-fungi and algae or blue green algae
Oxpecker on giraffe (SLIDE)
Raven on African bufallo (SLIDE)
Cleaner wrass, red snapper, sabre toothed blenny
(SLIDES) mimicry
Estrilded finch & brood parasite long tailed paradise
willow bird (mimicry) (SLIDE)
Pollination, cross pollination - avoid inbreeding
salvia male and female mature differently
carrion flower beetles, flies
Bees, (UV ultraviolet) Hummingbirds, (red)
Bats honey possom
Orchid - wasp (coevolution, mimicry)SLIDE
on flower beetles, flies
Bees, (UV ultraviolet) Hummingbirds, (red)
Bats honey possom

This page was last updated 7/25/02

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