Transcript Geologic Time

Chapter 13 – Geologic Time
13.1 Evolution and
Geologic Time
1.The geologic time scale is a
record of Earth’s history that
shows events, time units and
ages.
2. It is subdivided into smaller
units based on:
1. The types of life-forms living
at the time.
2. Geologic events occurring
at the time.
3.
Eras- largest – based on lifeforms.
Periods- divide eras – based on
life-forms and geologic events.
Epochs- divide periodssmallest amount of time.
4. Organic evolution – the
change in life-forms through
time.
5. Species- a group of organisms
that normally reproduce only
among themselves.
6. When 2 different species
breed their offspring are unable
to reproduce.
Tigon – male tiger + female lion
Liger – male lion + female tiger
Males are sterile in both species
Albert's Squirrel
South Rim Grand Canyon
Kaibab Squirrel
North Rim Grand Canyon
7. Natural selection – organisms
with traits that are suited to a
certain environment have a
better chance of surviving to
reproduce.
First proposed by
Charles Darwin in 1836.
8. The main cause of evolution
of new species is
1. changes to environments
2. competition with others for
resources
9. The Earth process most
responsible for changing
environments is
plate tectonics.
10. Endangered – when only a
small number of members are
living.
11. Extinct – when none of its
members are living.
12. 3 ways humans contribute
to extinctions.
1. destruction of habitat
2. competition for same food
supply
3. overhunting
1. Precambrian - Longest
geologic time unit in Earth’s
history.
Began: 4600mya (4.6bya)
Ended: 570mya
2. Precambrian fossils are sparse
because:
1. Rocks are deeply buried or
eroded away.
2. Rocks have been changed by
heat and pressure.
3. Early organisms were softbodied – no hard parts.
3. Cyanobacteria – bacteria +
algae. They photosynthesize.
Form stromatolites.
Appeared: 3.5 billion years ago
Take in: CO2
Release: O2
4. Cyanobacteria were important
because: They changed Earth’s
atmosphere by adding free O2 to
the air. The ozone layer formed
protecting organisms from UV
rays. Single-celled organisms
evolved into complex organisms.
5. Invertebrate- animal without a
backbone.
Appeared: near the end of the
Precambrian.
Ex: jellyfish, sponges, worms
6. Evolutionary advancement
that marked the beginning of
the Paleozoic:
when organisms developed
hard parts.
7. Paleozoic – “ancient life”.
8. Life-forms that were most
abundant during the Paleozoicocean dwelling (marine )
organisms.
Why? Warm, shallow seas covered
most of the Earth.
Ex: trilobites, brachiopods,
cephalopods, crinoids.
9. Vertebrate – animals with a
backbone.
Appeared: Ordovician Period
Ex: jawless fishes, bony fishes,
reptiles, mammals
10. Amphibian – vertebrates that
live on land but must return to
water to reproduce (lay eggs).
Appeared: Devonian Period
Ex: frogs, salamanders
11. Reptiles – vertebrates that live
entirely on land – eggs have a
leathery or mineralized
covering.
Appeared: Late Carboniferous
(Pennsylvanian Period)
Ex: tortoises, snakes, lizards,
crocodiles.
12. Appalachian Mountains
formed at the end of the
Paleozoic.
13.What marked the end of the
Paleozoic?
1. Largest mass extinction in
Earth’s history.
2. Formation of Pangaea.
1. Mesozoic – “Middle Life”
aka – “Age of Dinosaurs”
2.All continents are
still together as Pangaea
3. Laurasia – North America,
Europe, Asia, Greenland
3. Gondwanaland – South
America, Africa, Antarctica,
India, Australia
4. Small dinosaurs first appeared
in the Triassic Period.
Sellosaurus
Coelophysis
5. Evidence that dinosaurs were
warm-blooded:
1. Tracks indicate they were fastmoving.
2. They traveled in herds and
nurtured their young.
3. Bone structure resembles
warm-blooded animals.
6. Birds first appear in the
Jurassic Period
7.
Archaeopteryx
had wings and
feathers like a
bird, but teeth,
claws and a tail
like a dinosaur.
8. Mammals first appeared in the
Triassic Period.
9. Traits allowing mammals to
survive:
1. Hair or fur covering their
bodies.
2. They are warm-blooded.
3. Produce milk to feed their
young.
10. Gymnosperms – "naked seed
plant", no fruit covering their
seeds.
First appeared: Devonian Period
Ex: ferns, palms, ginkgos, pines
11. Angiosperms – flowering
plants. Produce seeds with a
hard outer covering and/or fruit.
First appeared: Early Cretaceous
Period
Ex: fruits,
vegetables,
flowers,
flowering trees
11. The end of the Mesozoic Era
was marked by:
Break-up of Pangaea, seas drained
from lands, extensive volcanism,
extinction of dinosaurs.
12. Cenozoic – "Recent Life"
aka "Age of Mammals"
13. The Alps in Europe form from
collision between African and Eurasian
plates.
14. The Himalaya
Mountains formed
from the collision between
the Indian and Eurasian
plates.
15. Placental mammals – nourish
their young internally from a
placenta. Offspring born live &
independent.
First appeared: Cretaceous Period
Ex: rodents, bats,
dogs, cats, cows,
humans
16. Marsupials – offspring are
born immature – must complete
development in a pouch.
First appeared: Cretaceous Period
Ex: kangaroo,
koala, wombat,
opossum
17. Australia has the greatest
number of marsupials.
The size of a
Koala just after
birth, crawling
to the pouch.
Monotremes – egg-laying mammals
18. Homo sapiens first appeared
about 500,000 years ago.
Homo sapiens neanderthalensis
appeared about 250,000 years ago.
Homo sapiens sapiens appeared
about 100,000 years ago.
We see the emergence of specifically
human activities, such as art and
religion.
19. Humans have been the
dominant life form for the past
10,000 years.
Starting about 10,000 years ago,
agriculture, the domestication of
animals, cities, and writing soon
followed.