Prentice Hall Biology

1
Concept Map
Section 17-2
Evolution of Life
Early Earth was hot atmosphere contained
poisonous gases.
Earth cooled and oceans condensed.
Simple organic molecules may have formed in the
oceans..
Small sequences of RNA may have formed and
replicated.
First prokaryotes may have formed when RNA or DNA
was enclosed in microspheres.
Later prokaryotes were photosynthetic and
produced oxygen.
An oxygenated atmosphere capped by the ozone
layer protected Earth.
First eukaryotes may have been communities of
prokaryotes.
Multicellular eukaryotes evolved.
Sexual reproduction increased genetic
variability, hastening evolution.
2
Figure 17-8 Miller-Urey Experiment
Section 17-2
Mixture of gases simulating atmospheres of early
Earth
Spark simulating lightning storms
Cold water cools chamber, causing droplets to form
Condensation chamber
Water vapor
Liquid containing amino acids and other organic
compounds
3
Figure 17-12 Endosymbiotic Theory
Section 17-2
Chloroplast
Plants and plantlike protists
Aerobic bacteria
Ancient Prokaryotes
Photosynthetic bacteria
Nuclear envelope evolving
Mitochondrion
Primitive Photosynthetic Eukaryote
Animals, fungi, and non-plantlike protists
Primitive Aerobic Eukaryote
Ancient Anaerobic Prokaryote
4
Geologic Time Scale with Key Events
Section 17-3
(millions of years ago)
Key Events
Era
Period
Time
Glaciations mammals increased humans Mammals
diversified grasses Aquatic reptiles
diversified flowering plants mass
extinction Dinosaurs diversified
birds Dinosaurs small mammals cone-bearing
plants Reptiles diversified seed plants mass
extinction Reptiles winged insects diversified
coal swamps Fishes diversified land vertebrates
(primitive amphibians) Land plants land animals
(arthropods) Aquatic arthropods mollusks
vertebrates (jawless fishes) Marine invertebrates
diversified most animal phyla evolved Anaerobic,
then photosynthetic prokaryotes eukaryotes, then
multicellular life
Cenozoic Mesozoic Paleozoic Precambrian Ti
me
Quaternary Tertiary Cretaceous Jurassic Triassic P
ermian Carboniferous Devonian Silurian Ordovician
Cambrian
1.8present 651.8 14565 208145 245208 290245
363290 410363 440410 505440 544505 650544
5
Patterns of Evolution
Section 17-4
Macroevolution refers to large-scale evolutionary
patterns and processes that occur over long
periods of time. Includes extinction, adaptive
radiation, convergent evolution, coevolution,
punctuated equilibrium, and changes in
developmental genes.
6
Extinction

• More than 99 of all species that have every
  lived are now extinct.
• Occur because species compete for resources and
  environments change (natural selection).
• Mass extinctions wiped out entire ecosytems. Food
  webs collapsed and disrupted energy flow through
  the biosphere.
• Most mass extinctions caused by several factors.
• Large volcanoes erupting, continents moving, sea
  levels changing.
• Leads to burst of evolution as species fill
  niches.

7
Adaptive Radiation

• A single species or a small group of species has
  evolved, through natural selection and other
  processes, into diverse forms that live in
  different ways.
• Darwins finches more that a dozen species
  evolved from a single species.
• Dinosaurs ruled earth for about 150 million
  years.
• Mammals disappearance of dinosaurs lead to
  adaptive radiation of mammals.

8
Convergent Evolution

• Process in which unrelated organisms come to
  resemble one another.
• Groups of different organisms, such as mammals
  and dinosaurs, undergo adaptive radiation in
  different places or at different times but in
  ecologically similar environments. Face similar
  environmental pressures. Natural selection molds
  different body structures into modified forms
  (arms and legs into wings and flippers).
• Analogous structures look and function
  similarly but are made up of parts that do not
  share a common evolutionary history.

9
Coevolution

• Organisms that are closely connected to one
  another by ecological interactions evolve
  together.
• Flowers and pollinators
• As evolutionary change in one organism may also
  be followed by a corresponding change in another
  organism.
• Analogous structures look and function
  similarly but are made up of parts that do not
  share a common evolutionary history.

10
Punctuated Equilibrium

• Fossil records show that some organisms evolved
  gradually over time.
• Others are in equilibrium have changed little
  over time.
• Long, stable periods are interrupted by brief
  periods of more rapid change punctuated
  equilibrium. May occur when
• a small population becomes isolated from the main
  part of the population or a small group migrates
  to a new environment.
• a mass extinction occurs.
• Organisms evolve rapidly to fill available niches.

11
Flowchart
Section 17-4
Species
that are
in
under
under
form
in
in
can undergo
can undergo
can undergo
can undergo
can undergo
12
Video Contents
Videos

• Click a hyperlink to choose a video.
• Geologic Time
• Evolution of Cells

13
Internet
Go Online

• Career links on fossil preparators
• Interactive test
• For links on the fossil record, go to
  www.SciLinks.org and enter the Web Code as
  follows cbn-5171.
• For links on eukaryotic cells, go to
  www.SciLinks.org and enter the Web Code as
  follows cbn-5172.
• For links on extinction, go to www.SciLinks.org
  and enter the Web Code as follows cbn-5174.