Transcript Evolution Patterns

Evolution Patterns
of Multicellular Life
OA- How would sexual
reproduction speed up evolution?
OA- How would sexual
reproduction speed up evolution?
• Sexual reproduction would speed up
evolution because it increases variation
among the offspring. Natural Selection
depends upon variation and this drives the
process of evolution. Most prokaryotes
reproduce asexually by duplicating their
DNA and splitting into two identical cells.
Sexual reproduction shuffles the genes
and makes new combinations.
Precambrian
1. Simple anaerobic life
Prokaryotes
2. Photosynthetic forms
3. Aerobic life forms and
Eukaryotes
4. Multicellular forms begin
to be more complex
5. Only sea life
Paleozoic Era
543 to 248 Million Years Ago
• Cambrian Period
• Ordovician Period
• Devonian Period
• Carboniferous
Period
Cambrian Period
• Cambrian Explosion
• Organisms had hard
parts: shells and
exoskeletons
• Invertebrates:
jellyfish, worms,
sponges
• Brachiopods: two
shelled – common
• Trilobites - Arthropods
Ordovician and Silurain Periods
• Ancestors of modern
Octopus and Squid
• More Arthropods (first
to live on land)
• First vertebrates:
jawless fish
• First land plants- from
aquatic ancestors
grew in damp places
Devonian Period
• Vertebrates begin to
invade the land
• Age of Fishes: most
have jaws, skeletons
and scales
• Ability to crawl on leglike fins but still fully
aquatic ancestors to
amphibians
Carboniferous and Permian
Periods
• Life expanded to
include reptiles,
• Winged insects
• Giant ferns and
Swampy Forests
• Ancient plants formed
deposits in the
sediment that became
coal “Carboniferous”
Mass Extinction
• End of Paleozoic Era
mass extinction
• 95% of complex life
including plants and
animals on land and
in sea.
• Many fish and reptiles
survived but not
trilobites
Mesozoic Era
1. Triassic Period
2. Jurassic Period
3. Cretaceous Period
• Lasted 180 million
years –Then
ANOTHER mass
extinction
Triassic Period
• Survivors of Permian
Extinction became
main life forms
• Fish, insects, reptiles
• Age of Reptiles
• Mammals also appear
and are the size of a
mouse
Jurassic Period
• Dinosaurs dominate
for about 150 million
years
• First birds – believed
to be closely related
to dinosaurs
Cretaceous Period
Flying reptiles become
extinct
• Turtles and crocodiles
swim among fish and
invertebrates
• Flowering Plants
Dominate land
• Then ANOTHER
mass extinction
Cenozoic Era
• Tertiary Period
• Quaternary Period
Tertiary Period
• Climate generally
warm and mild
• Whales and
dolphins evolve
• Grazing animals
• Some mammals
and birds
become large
Quaternary Period
Mammals evolve
Earth’s climate cooled
and a series of ice
ages begin
• Glacial Advance and
Retreat over Europe
and North America
• Glaciers melt sea
levels rise
Patterns of Macroevolution
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1. Extinction
2. Adaptive Radiation
3. Convergent Evolution
4. Coevolution
5. Punctuated equilibrium
6. Changes in Developmental Genes
Extinction
• More than 99% of all
species that ever
lived are now extinct
• Natural Selection
pressures some to
adapt or become
extinct
• Then a burst of
evolution that produce
new species
Adaptive Radiation
• A single species
evolves through
Natural Selection
into diverse forms
• Darwin’s finches:
a dozen species
from a single
species
Convergent Evolution
• Unrelated organisms
that look alike
• Similar environments
or demands: moving
through air or water,
eating similar food…
• Produce modified
structures: wings,
flippers
Coevolution
• Evolve together
• One organism changes followed by a change in another
who has a close relationship
Punctuated Equilibrium
• Long stable periods
interrupted by brief
periods of rapid
change
• Evolution proceeds at
different rates over
time
• Sometimes rapidly to
fill available niches
like after extinctions
Developmental Genes
• hox genes guide
development in
embryo
• Small changes to hox
genes can cause big
changes to organisms
• Feet where antennae
should be???
Assignment
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Page 434 (Prentice Hall Book)
Questions 1-3
Page 440 (Prentice Hall Book)
Questions 1-4