Download EVOLUTION NOTEScomplete2010 - Fredericksburg City Public

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EVOLUTION NOTES.I. The Puzzle of Life’s Diversity
• ___________________-variety of organisms
• _________________-change over time
• Voyage of the Beagle
– Charles Darwin-sailed____________________(1831) and collected many
scientific observations –particularly of interest at the area
around S.America and the Galapagos Islands
– Darwin collected ___________ remains-some resembled living
organisms and some did not---indicating species had
disappeared.
– Observed great diversity and saw so many organisms were well
suited to their environments and various patterns ----leaving
him w/ many questions…
– Although the Galapagos Islands were very near S.America,their
climates were different than S.America and each other.The
_________________ and iguanas varied in predictable ways from island
to island/also many observations on variations in birds-eg. Size
or shape of beak.
• After returning to England , he began to wonder if the animals on
different islands were once members of the same species.
II. Ideas that shaped Darwin’s thinking
– Predominate thought was that the earth and inhabitants were
only a couple thousand years old.
– __________________ published a detailed hypothesis about the
geological forces that have shaped the earth-proposing layers of
rocks formed slowly and the physical earth was shaped by a
variety of forces..
– _____________________________________ wrote Principles of Geology .--stressed that scientists must explain past events based on
processes they can actually observe---eg. By volcanoes that we
still observe may we get an idea of how the earth has changed
– _________________(1809)-realized organisms change over time but he
felt that selective use or disuse of organs caused organisms to
acquire or lose traits
– 1) _____________He said all organisms have a tendencies
towards perfection ..thus continually acquiring
characteristics to improve themselves----Thus he would
say birds fly because they long ago tried to and their wings
kept developing over the generations to fly.
– 2) ________________if something is used it is transformed for
that purpose while if it not used,it would eventually
disappear
– 3)____________________.---If a giraffe stretched its neck to reach
its food,it would pass that trait on…
– 4)Evaluating Lamarck- incorrect in many ways-
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He did not know an organism’s experiences or
behavior have no effect on inheritance
Population Growth-_____________-reasoned that if the human population
continued to grow unchecked,sooner or later there would be
insufficient space & food---war,famine and disease work against this
Darwin realized this applied less to humans than other animals and
plants because _______________________________________
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Notes –Evolution cont’d
Chapter 15
III. Darwin Presents His Case
A. publication
 1858-Alfred Russel Wallace summarized the thoughts on
evolutionary change Darwin had been looking @ for 25
years…This gave Darwin the incentive to publish his work
 !859—Darwin Published “On the origin of Species…”proposed the
mechanism for evolution to be ________________________________________
B. Inherited Variation and Artificial Selection
 Members of each species vary from one another
 Some variation heritable-passed on
 _____________________________________selective genetic variation where
nature provides the variation and humans select to breed for this
characteristic
C. Evolution by Natural Selection
1) Struggle for existence
 Applying Malthus’ principles,he realized high birth rate and
shortage of resources produced _______________________-struggle
for existence---faster,etc. avoid being caught
2) Survival of the Fittest
 _____________________=ability of an individual to survive and
reproduce
 ____________________________=any inherited characteristic that
increases an organism’s chance of survival
 Organisms w/ low levels of fitness are unlikely to survive
and reproduce
 _________________________________________=survival of the
fittest….may inherited characteristics of a population
3) Descent with Modification
Over long periods ,natural selection produces organisms that have different
structures,establish different niches,or occupy different habitats---each
species descends _________________________________________________________________.
o Implies all living organisms are related to each other
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o ________________________________________all species-living and extinct
were derived from common ancestors
D. Evidence of Evolution
1) Fossil Record-record of the history of life on earth-comparing fossils
from different layers
o Felt the earth was millions of years old
o Since Darwin,people have discovered many transitional
species in fossilized form
o Gaps remain—providing some uncertainty about how some
species evolved
2) Geographic Distribution
 With reference to birds he observed,Darwin felt although they
varied,they descended with modification from common mainland
S.American ancestor
 Animals w/certain similarities between areas developed this way
due to similar ecological conditions
3) Homologous Body Structures----structures that
have different mature forms but develop from
the same embryonic tissue
Example:The bones of a bird skeleton more closely resemble homologous
bones of certain reptiles than that of bats
o
o _____________________________________-traces of homologous
organs….appear to have no function
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4) Embryological Similarities-many embryos look
esp. similar during certain stages of
development…producing homologous
structures
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



 Summary of Darwin’s Theory
Individuals differ and some can be ___________________________.
Organisms produce more offspring that can survive and many do not
___________________________________.
Organisms __________________________for limited resources.
Each unique organism has unique advantages and disadvantages in struggling
for existence---Those best suited will reproduce,passing on their traits.
Species alive today descended with modification from ancestral
species…uniting us in a single tree of life
 Strengths and Weaknesses
 Continues to change as new data and technology develop
 Argument about extinction
 Origin of life
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Darwin’s Finches
Evolution cont’d-pieces of Chapter 16 & 17
 _____________________________=all genes,inc. all the different alleles,that
are present in a population
 _____________________________of an allele= # times that the allele occurs
in a gene pool,compared with the # of times other alleles for the
same gene occur.(often a %)
 In genetic terms ,evolution is any change in the relative frequency
of alleles in a population.
 Sources of genetic Variation1. mutations
2. gene shuffling
o Natural selection can affect the distribution of phenotypes
in any of the 3 following ways:
1. Directional selection-Individuals @ one end of
curve have higher fitness than those @ middle or
other end-Example-birds w/ large,wide beaks can
crack large seeds….If the supply of small seeds
decreases,they dominate
2. _________________________-individuals near center of
curve have higher fitness—example-babies of
average weight survive better than very low or high
birth weights.
3. ______________________________-individuals @ upper and
lower end of curve have higher fitness than
individuals near middle-example mid-sized seeds
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become less common and large beaked or small
beaked birds both benefit.
 _________________________________= random change in allele frequency
1.
2.
3.
4.
5.
see p.400
 __________________________________Principle-allele frequencies in a
population will be constant unless one or more factors change it.
5 conditions for it to hold
genetic equilibrium from generation to generation
random mating
large pop.
no emigration or immigration
no mutations or natural selection
 ___________________= formation of new species
Due to Isolation-reproductive isolation due to
behavorial,geographic or
______________________isolation(reproduce @
different times)
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 ______________________________are scientists who
study fossils
 How fossils form:
1. sedimentary rock
2. sometimes an imprint and sometimes a
preserved remains
3. buried in resin-amber
4. tar pits
 Dating1. compare w/other sediments and fossils
2. radioactive dating using half lives-esp. C-14,since its half life =
5730 years
 Geologic Time scale-see p.421
 3 eras:Paleozoic,_______________________ and Cenozoic
1. Paleozoic-diversity of marine life
2. Mesozoic-increasing dominance of
Dinosaurs,flowering plants appear
3. Cenozoic-mammals evolved adaptations to allw
them to live in various environments
 _________________-are subdivisions of eras
Earth’s early atmosphere probably contained H-cyanide,CO2,CO,N,H2S and
H2O
Miller & Urey’s experiments suggested how mixtures of the organic
compounds necessary for life could have arisen from simpler
compounds.This was not totally accurate –ie. the experiment-but lead to
similar experiments-even producing nitrogenous bases .
~ 200-300 million after earth cooled to carry water, cells similar to bacteria
developed, beginning w/something similar to a cell membrane
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
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Next eukaryotic cells developed by______________________________________________
as a symbiosis formed between prokaryotes….eventually specializing into
organelles like________________________
Margulis supported this in the 1960’s w/the following evidence:
1. mitochondria and chloroplasts carry DNA similar to bacterial DNA.
2. mitochondria and chloroplasts have ribosomes similar to that of
bacteria
3. mitochondria and chloroplasts reproduce by binary fission a lot like
bacteria
Patterns of Evolution1. extinction
2. _____________________________________-single species evolve into several
different forms in different ways
3._________________________________________-unrelated organisms come to
resemble one another
4.__________________________________________-2 species evolve in response
to changes in each other over time
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5. ________________________________-long,stable
periods,interrupted by brief periods of
more rapid change
-------In spurts
6. __________________--opposite of punctuated
equil.---slowly over a long period of time
BIOLOGY NOTES -HUMAN EVOLUTION
NOTES_______________________
I. Primates
 HUMANS BELONG TO THE GROUP CALLED _____________that also include
monkeys and apes
 originally lived in trees
 strong hands ,fingers and ____________________thumbs
 relatively large brains w/ a degree of intelligence
 complex social behaviors
 extended parental care
 only humans can remain ____________-walking on 2 legs-for an extended time
 humans have the largest of primate brains
 humans have more developed speech
II. Primate Evolution
A. Apes
 usually larger than monkeys
 larger brains and no tail
 surviving
apes:________________,____________________,_____________________,and
gibbons
 genetic studies show chimps to be closest ape to
humans-----more than 90% genes identical
B. Prosimians and Anthropoids
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

____________________(means premonkey)-small monkeylike w/ large
forward facing eyes and are ____________________-active @ night--fossilized ones were rodent-like
 Modern Prosimians:__________,____________ and
________________
 _________________________means humanlike include New World monkeys of S. America
w/ prehensile tails-flexible tails(examplespider monkey)
 anthropoids in Europe,Asia and Africa evolved
into 2 groups 1)__________________________________
and 2)____________
Old World Monkeys have long prominent noses and non-prehensile tailsexample-Baboon
III. Early Hominids
 _______________all anthropoids belonging to human family

modern human:________________

____________________________are scientists who study the lives and cultures of
human through fossils and artifacts

probably there was usually more than one hominid @ a time
A. Australopithecus

Fossil evidence suggests the split between human and apes happened
between 5-8 million years ago

Oldest fossil found may be_____________________-meaning southern ape found in
southern Africa

1994-4.4 million y old - __________________________________

1924-_________________________________-2.7-2.1 mya

1974-____________________________________-Lucy-3-4mya

They are considered hominids because they are bipedal---note different
pelvis
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Austalapithecus brain still smaller

___________________________and _________________________-1-2 mya-thicker bones
B. Homo habilis

1964 the Leakies found ________________________-1st known to use tools-direct
ancestor of humans

1960's-another discovery of probably same species

larger brain
C. Homo erectus

even larger brain

migrated out of Africa and into Asia and Europe

may have been able to make fire
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IV. Homo sapiens

maybe 500,000 to 300,000 y ago
A. ________________________fossils found in Germany in 1856

subspecies of Homo sapiens

Europe and Asia

brains as large as humans

faces fairly similar w/ heavier brow

burials and decorated tools

religion
B. Cro- Magnons
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100,000 y a

shared earth w/ Neanderthals....may have blended into one group

may have drove Neanderthals to extinction
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1st fully modern human