Life

1
Lifes
Record
2
Early Earth

• Early earth was most likely very hot with lots of
  lava flow. Only Archea bacteria would have been
  able to survive in the early earth conditions.
• Gases coming from violent eruptions helped create
  earths atmosphere, such as water vapor, carbon
  dioxide, and nitrogen.

3
Fossils

• Evidence of an organism that lived in the past.
• Types
• Trace fossils
• Casts
• Imprints
• Petrified
• Molds
• Amber preserved and frozen fossils.

http//biology.st-and.ac.uk/sites/bellpet/fossils.
jpg
4
Fossilization Process

• Animal dies
• Gets covered by dirt/ sediments.
• Over time, layers and layers build up on remains.
• Earth movements reveal remains, and they are
  found.
• Pg.381 of text

5
Who are Paleontologists?

• Scientists who study fossils.
• By studying fossils, these scientists gain
  insight into what the past was like, what
  creatures lived at different times, and by doing
  this they construct the
• Geologic Time Scale.

6
Dating Fossils

• Relative Dating
• Fossils at the top of layers of earth are younger
  than those at the bottom.
• This is a geological law
• Cant be used to tell specific age of fossil
• Radiometric Dating
• Done by using the decay rate of radioactive
  isotopes, the Half Life the time it takes for
  half of the material to decay
• Most common used are
• Potassium 40, half life1.3 billion yrs older
  fossils
• Carbon 14, Half Life5730 yrs fossils less than
  50,000 yrs old

7
How did life begin Early Ideas

• Spontaneous Generation
• Idea that nonliving material could form life.
• Redis and Pastuers experiments disproved this
  idea.
• Redi experimented with flies, maggots, and meat.
• Pastuer experimented with broth.
• Biogenesis
• Living organisms can come only from other living
  organisms

http//biology.clc.uc.edu/graphics/bio104/redi.jpg
http//www.slic2.wsu.edu82/hurlbert/micro101/imag
es/hist9.gif
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Evolution of Life

• Two developments that preceded appearance of life
  on Earth
• Simple organic molecules form
• These molecules organized into complex organic
  molecules (proteins, carbs, nucleic acids)
• Protocells then formed
• Large, ordered structures enclosed in a membrane.
  It carried out some basic life functions such as
  growth and division.

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Evolution of cell
http//images.google.com/imgres?imgurlwww.siu.edu
/protocell/photos/siu1.gifimgrefurlhttp//www.s
iu.edu/protocell/photos2.htmh605w482prev/im
ages3Fq3Dprotocell26svnum3D1026hl3Den26lr3
D26ie3DUTF-826oe3DUTF-8

• First true cells
• Possibly prokaryotes that evolved from
  protocells.
• Were probably heterotrophs (feeding off of other
  things, such as organic molecules)
• Autotrophs evolved (photosynthesis begins), thus
  increasing concentration of O2 in atmosphere.

10
Endosymbiont Theory

• Proposed by Lynn Margulis in 1960s
• Proposes that
• Eukaryotes evolved through a symbiotic
  relationship with prokaryotes (sharing)
• Anerobic bacteria was engulfed (phagocytosis) and
  became chloroplasts.
• Evidence for this is
• Both chloroplasts and mitochondria contain their
  own DNA that is similar to that of prokaryotes
• Size of these organelles is equivalent or similar
  to that of prokaryotes
• That these organelles are membrane bound

http//www.mrs.umn.edu/goochv/CellBio/lectures/en
do/Image157.gif
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The Theory of Evolution
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What is EVOLUTION anyway?

• Evolution is change in a population over time.
• The word itself refers to CHANGE.

13
Charles Darwin

• Proposed the theory of evolution by natural
  selection.
• He came up with this theory through studying
  nature during his voyage on the HMS Beagle.
• During this voyage he explored life on the
  Galapagos Islands.
• He studied the large tortoises that are found
  there.
• Natural selection was proposed to explain how
  species changed over time.

http//academy.d20.co.edu/kadets/lundberg/darwin/d
arwin.JPG
http//www.victory-cruises.com/graphics/BEAGLE.gif
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Darwins Experiments

• He bred pigeons and studied traits the population
  inherited.
• By doing this he was using artificial selection
  (breeding for specific traits).
• He studied the traits that were passed down from
  the parent generation and looked at how they
  adapted to specific selective forces (things that
  cause adaptation).

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How does Natural Selection work?

• Different things happen to the environment that
  cause species to be forced to adapt. The ones
  that survive reproduce and pass on the selected
  for traits.
• These traits enable the offspring to survive
  until the environment changes and forces new
  traits to be selected for.

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Adaptations Take Time!!

• Adaptations are evidence for evolution. But these
  adaptations take time, and normally take a few
  generations.
• There are two different adaptations
• Structural
• Physiological

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Structural Adaptations

• Common examples are teeth size, claw size, ect
• More specifically
• Mimicry, this structural adaptation enables one
  animal to look like another. This may be used to
  resemble a dangerous animal for protection, or
  used by predators to capture prey.
• Camouflage, enables animals to blend in with
  their surroundings, helps in avoiding predators.

http//www.msmedia.com.au/Science/images/mimicry.j
pg
http//students.washington.edu/cochranb/hawaii/cam
ouflage.jpg
18
Physiological Adaptations

• These changes occur in the organisms metabolism.
• One example is the quick adaptations of bacteria
  to the lethal affect of penicillin, in other
  words they are becoming immune, requiring higher
  and higher doses to kill bacteria.
• Another example is increased pesticide resistance
  in plants and insects.

• http//forum1.sewanee.edu/palisano/wastewater/imag
  es/ecoli.jpg

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Other Evolution Evidence

• Fossil record show signs of evolution
• Anatomy of organisms
• Homologous structures, structures similar in
  arrangement, function, or both. This is evidence
  of evolution from a common ancestor.
• Analogous structures, body structures that do not
  have a common origin, but that are similar in
  function.
• Vestigial structure, a body structure that has no
  function, it is thought to be retained from
  evolutionary ancestor through heredity.

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Evidence continued

• Embryology
• This deals with the similarities in embryos (the
  first stage of life) of different species.
• Biochemistry
• This uses the comparisons of DNA or RNA of
  different species to show evolutionary
  relationship.

http//www.cord.edu/faculty/landa/courses/b315f99/
sessions/phylogeny/embryology.jpg
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Primate Evolution
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What are Primates?

• They are a group of mammals.
• This group includes lemurs, monkeys, apes, and
  humans.
• They come in all different shapes and sizes.

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Common Characteristics of Primates

• They all have opposable thumbs.
• Their brain volume is large compared to their
  body size.
• Vision is the dominant sense, binocular vision.
• Arms adapted for a great range of motion.
• Flexible joints
• Feet are able to grasp things.

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How did they evolve?

• Scientist use fossils, comparative anatomical
  features (body similarities), and DNA to propose
  evolution ideas.
• Prosimians evolved first.
• These were small present day primates such as
  lemurs.

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Anthropoids Evolve...

• Anthropoids are humanlike primates.
• They evolved after the prosimians.
• They includes apes and humans.

http//www.mosartdesigns.on.ca/largeart/paintings-
ape.jpg
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Differences of Anthropoids

• They have more complex brains than prosimians.
• Larger and different skeletal features (more
  upright posture)
• Examples are Gibbons, orangutans, chimpanzees,
  and gorillas.

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Old World and New World Monkeys

• These are two classes monkeys are broken up into.
• Old world are generally larger, and may be
  terrestrial.
• New World live in South and Central America.
• They are all Arboreal (living in the trees) and
  have long, muscular prehensile tail.

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Humans tied in

• Scientist theorize that we were the last to
  evolve.
• We have an even larger brain capacity and walk
  upright.

http//www.bio.psu.edu/faculty/hedges/primate.gif
29
Hominoid Evolution

• Hominoids or humans began to evolve in Asia and
  Africa as the fossil records shows us.
• Hominoids include apes and humans.
• Scientists think that gibbons were the first to
  evolve, then orangutans, followed by the African
  apes, chimpanzees, and gorillas. One of these
  being or possible ancestor.

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Human Ancestry
http//www.centerfortheperson.org/HUMAN20EVOLUTIO
N.jpg

• Scientist believe that there were two lines
  evolving. One being humans, and the other were
  the African apes- gorillas and chimpanzees.
• Bipedal adaptation of humans sets us apart.
  (walking upright)

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Time line of evolution
Homo sapiens
Homo erectus
Homo habilis
A. boiseri
A. robustus
Australopithecus africanus
Australopithecus afarensis
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Development of culture

• The first known humanoid fossils was
  australopithecine.
• Next came the Neanderthals who lived in Europe,
  Asia, and the middle East 35000-100000 yrs ago.
• Cro-Magnons then became the most recent modern
  human ancestor.

http//cator.hsc.edu/kmd/caveman/shanidar.jpg
33
Neanderthals Cro-Magnons

• Neanderthals were the first humanoids to use
  tools for hunting and to use fire.
• Through them a semblance of culture developed.
• Cro-Magnons further developed the use of language
  and art, primarily cave drawings. They also
  advanced tool making.