THE THEORY ORY OF EVOLUTION UTION Evoluti tion on Process by - - PDF document
2/18/2013 THE THEORY ORY OF EVOLUTION UTION Evoluti tion on Process by which living organisms descend from ancient ones by a series of changes resulting in some species becoming extinct and new species developing from previous ones.
iation ion exists within the genes of every population or
population or species are better er suit ited ed to surviv ive (as a result
population able to survive and reproduce tend to sprea ead in that popula lation ion.
ls and many other sources that living species evolved from organisms that are extinct.
1801: Jean Lamar arck ck (French)
y of desire
become more fit for environment ex: ant eaters develop long snouts
y of use and disus suse
ex: snakes- didn’t use legs so disappeared whales- used to be land creatures, legs became fins
y of inheritance ance
ex: snakes that lost legs passed trait weight lifters would produce muscular offspring 1859: Charles s Darwin (English) Influences in Darwin’s theory of evolution:
Lyell (geologist) said earth changed over time
cial al select ction
Process whereby with human intervention superior specimens are bred to produce superior offspring with desired traits ex: larger bulls cows that produce more milk larger ears of corn
ulat ation
Malthusian Doctrine (human population is controlled by famine, disease, and war)
Parts of Theo eory
ion
le to surviv ive
resources) ex: pond ecosystem – cattails compete with duckweed for surface of lake water
etic varia iatio ion
recombination)…………. this is normal. exception: identical twins
ival of the e fittes est
survive and reproduce
By sprayin ing g crops s with poiso sons s to kill l insect pests, s, humans s have favo vored d the reprodu ductio ion of insects s with inherit ited d resista stance to the poiso sons over those with no resista stance
“Origin of the Species through Natural Selection”
related to apes
arguments
natural selection works
evolutionary change in genetic terms
the gene pool of a population Popula lation ion: collection of individual of same species in specific area that can successfully breed.
Gene e pool: common group of genes Relativ ive e frequen ency: how often alleles show up
ion: genetically controlled characteristics (physical or behavioral traits) that increase an
ecies ies: : group of organisms that breed and produce fertile offspring
increases fitness, members of a species can evolve together
ecia iation ion: development of a new species thru evolution
ive e Isola
ion: two populations of same species do not breed with each other due to geographic separation
In this model, , arrows symbol
e population
e geog
ed, , then come toget ether er again at a later time. e.
where same species becomes different over time and can no longer breed
fertile periods ex: isolation by grand canyon Kaibob squirrel Abert squirrel
ion (gen ene e flow) movement of large numbers of organisms of same species from one
environment to another (immigration or emigration)
gene pool Ex: camels: originated in N America but migrated around the world, ice age destroyed most except those in scattered areas Asian African Llama
ive radia iation ion (div iver ergen ent evolu
ion): process by which different species arise from one common ancestor
them to survive in different environments
ex: Darwin’s finches
Adapt aptive radiat ation
and chain n may lead to several al new bird speci cies s evolving ng from one found nding ng popul pulat ation.
he
Examples of adaptive radiation, cont.
Homol
uctur ures: : structures which developed from a common ancestor, but have changed over time due to different purposes similar ar struct uctur ures s less ss similar ar struct uctur ures
platypus kangaroo anteater
nvergent nt evolut ution
independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.
because they share same environment
analog
uctur ures: similar in appearance and function, but different origins with different internal structures (each evolved independently) bat wing ng v.s. . bird wing ng diss ssimilar ar struct uctur ures s mor
ar struct ctur ures
etic Drif ift: chance changes in gene pool from generation to without natural selection
ilibriu ium: organism does not change every much over time ** explains gaps in the fossil record **
ed equilibr ilibriu ium: long stable period interrupted by brief periods of change (sometimes events occur to disturb equilibrium)
Acacia ia ants and acacia ia trees es
Pollin lination ion
from bees
ilarit itie ies: : evidence of a common ancestor
notochord (stiffening rod of cartilage) in the back
embryos, yolk sac that produces the first blood cells and germ cells
many organs
l recor
rock, with the youngest usually on top, and the
(sedimentary rock)
(fossilized tree sap)
soft outer coverings on
imprints
lived on Earth are now extinct.
ive e anatom
Vestigial structures es (organs) Homol
es
Snake Vestiges of pelvic girdle and leg bones of walking ancestors Whale Set of bones that are clearly homologous with the pelvis of any four-limbed vertebrate
emical l simila ilarit ities ies
blood chemistry)
Species Amino Acid Differences from Human Hemoglobin Protein Gorilla 1 Rhesus monkey 8 Mouse 27 Chicken 45 Frog 67 Lamprey 125
igia ial l structures es:
functions or develop new ones coccyx appendix muscles behind ears
Allows us to:
environment