Natural Selection, Natural Selection, Evolution & Evolution &

Implications for Implications for the Conservation of the Conservation of

Wildlife Wildlife

EvolutionEvolution

It’s the process that drives-• the diversity of reproductive strategies we’ve

studied…• the ongoing relationships between predator

and prey…• the patterns of wildlife distributions around

the globe…• responses to disturbances…• guides the migrants… • as well as the demise of all the species that

have become extinct throughout all of time…

Taxonomy: BirdsClass Aves (birds)

Order Anseriformes (ducks, geese, swans, and relatives) Order Galliformes (chicken-like birds) Order Caprimulgiformes (nightbirds) Order Apodiformes (hummingbirds and swifts) Order Balaenicipitiformes (shoebill or whale-headed stork) Order Charadriiformes (shorebirds and relatives) Order Ciconiiformes (storks and relatives) Order Coliiformes (mousebirds) Order Columbiformes (doves and pigeons) Order Coraciiformes (kingfishers and relatives) Order Cuculiformes (cuckoos and relatives) Order Falconiformes (diurnal birds of prey) Order Galbuliformes Order Gaviiformes (loons) Order Gruiformes (coots, cranes, and rails) Order Mesitornithiformes (mesites) Order Musophagiformes (turacos) Order Opisthocomiformes (hoatzin) Order Passeriformes (perching birds) Order Pelecaniformes (pelicans, tropicbirds, cormorants, and relatives) Order Phoenicopteriformes (flamingos) Order Piciformes (woodpeckers and relatives) Order Podicipediformes (grebes) Order Procellariiformes (tube-nosed seabirds) Order Psittaciformes (parrots) Order Sphenisciformes (penguins) Order Strigiformes (owls) Order Trogoniformes (trogons) Order Turniciformes (buttonquail) Order Struthioniformes (cassowaries, emus, kiwis, ostriches, and rheas) Order Tinamiformes (tinamous)

And even for humans, it drives

…and who will notwho will survive…

And may just influence what happens next on this

graph…

Nothing in biology makes sense except in the light of

evolution” -Theodosius Dobzhansky

Evolution through natural selection

is the foundation of modern ecology,

biology and medicine.

Theory or Fact?Theory or Fact?

• In everyday vernacular, a theory is “a guess”.

• As a scientific term, a theory is “a statement of what are held to be the general laws, principles, or causes of something known or observed” (OED)

• A scientific theory is testable and can make verifiable predictions

• In fact, it has been noted that we know more about the mechanisms of evolution than we do gravity, the nature of light, sleep, the weather, and something even more nebulous and stormy… love.

Throughout much of human history, the dominant perspective (and still is in some of the less educated parts of the world… and country), was that everything was divinely created in its present form, and that this Creator also orchestrated their interactions not unlike a master puppeteer.

Theologist: “ What have you learned about the mind of God in the course of your studies of biology?”

J.B.S.Haldane: “ Madame, only that he had an inordinate fondness for beetles.”

J.B.S. Haldane

Charles Darwin(1809-1882)

Published one of the most

influential books ever written-

On the Origin of Species-

in 1859

2009 marks the 200th anniversary

of his birth and 150th anniversary

of the publication of OtOoS

The Galapagos Islands

What is Natural What is Natural Selection?Selection?

“principle by which each slight variation [of a trait], if useful, is preserved” – Darwin

Natural Selection• Individuals within populations are variable for

nearly all traits• Individuals pass on their genes to offspring• More offspring are produced than can survive• Individuals that survive and go on to reproduce

(the most) are those with the varieties (alleles) that best adapt them to their environment

• Outcome: alleles associated with higher fitness increase in frequency from one generation to the next

Artificial Selection

Artificial Selection

Natural Selection is also a part of population regulation

• The reproductive potential of populations is great, but

• populations tend to remain constant in size, because

• populations suffer high mortality.

• Individuals vary within populations, leading to

• differential survival of individuals.

• Traits of individuals are inherited by their offspring.

• The composition of the population changes by the elimination of unfit individuals

• Rabbits should cover the earth, but

• they don’t, because

• many are caught by predators.

• Some rabbits run faster than others,

• and escape from predators

• and so do their young.

• Populations of rabbits, as a whole, tend to run faster than their predecessors.

From Ricklef’s “The Economy of Nature” Second Edition

Important PointsImportant Points

• Weak forces operating over long periods of time create large and dramatic change.

• Natural selection is the non-random survival of random variants

• Natural selection- by itself- is not evolution. It is the mechanism that can lead to evolution.

• Natural selection takes place within a generation, but evolution takes place across generations.

Gregor MendelContemporary of Darwin“father of genetics” -1866Heritable traits & dominance

Watson & CrickMechanism of inheritanceDNA1953

Peter & Rosemary Grant

Daphne Major

Started research project on Darwin finches in 1973.

Geospiza fortis

Graph showing the distribution of beak depths for medium ground

finches in Year 1

34

la Niña = Drought

el Niño = Rains

Drought (la nina) Wet (el nino)

In 1975, the rainy season came and went with nary a drop of rain (el Niño)

Following the droughtof 1977, 85% of the medium ground finch population died.

Year 3 Data

40

Caltrop seeds (Tribulus)

• This demonstrates natural selection, but the story is not quite over…

• The year of the drought, no young were produced

• After the drought, the 15% that survived represented birds with larger bills.

• These individuals did breed the following year.

• What do think their offspring looked like?(Small beaks? Medium beaks? Big beaks?)• This is evolution.

Other evidence for evolution

• Common structures (homologous)• Analogous structures (convergent

evolution)• DNA Research• Fossil Record

• Embryonic development• Vestigial Organs & Structures• Imperfections in Structure• Drug-Resistant Bacteria

Homologous StructuresHomologous Structures~ common ancestor ~~ common ancestor ~

Homologous StructuresHomologous Structures

Convergent EvolutionConvergent Evolution~ Physical adaptations to similar ecological ~ Physical adaptations to similar ecological

conditions~ conditions~

Convergent EvolutionConvergent Evolution

DNADNA - species that appear to be more distantly related from their

positions in the fossil record are found to have

correspondingly greater differences in their DNA than species that appear more closely related in the fossil record.

FossilsFossils

Conservation ConnectionConservation Connection

““It is not the strongest of the It is not the strongest of the species that survives, nor the species that survives, nor the most intelligent, most intelligent,

but the one most responsive to but the one most responsive to change.” change.”

–Charles Darwin–Charles Darwin

Punta AltaPunta Alta““a perfect catacomb for monsters of extinct races”a perfect catacomb for monsters of extinct races”

We are changing the world faster than species are able to adapt to these changes.

Humans as an Evolutionary Force

• Human-induced evolution caused by unnatural selection through harvest of wild animals (Allendorf, F.W. and J. J. Hard. 2009. PNAS. Vol. 106)

• The nature of fisheries- and farming-induced evolution (Hutchings, J.A. and D.J. Fraser. 2007.Molecular Ecology. Vol.17)

• Rapid human-induced evolution of insect–host associations (Singer, M., C.D. Thomas and C. Parmesan. 1993. Nature. Vol. 366)

• Humans as the World's Greatest Evolutionary Force (Palumbi, S.R. 2001. Science. Vol. 293)

Evolution BooksEvolution Books~The Old Classics~~The Old Classics~

Evolution BooksEvolution Books~The New Classics~~The New Classics~

“It is a century now since Darwin gave us the first glimpse of the origin of species. We know now what was unknown to all the preceding caravan of generations: that men are only fellow-voyagers with other creatures in the odyssey of evolution. This new knowledge should have given us, by this time, a sense of kinship with fellow-creatures; a wish to live and let live; a sense of wonder over the magnitude and duration of the biotic enterprise.”

~Aldo Leopold