Transcript BIO117H - willisworldbio

THE FOSSIL RECORD
OBJECTIVES: 17.1
Describe the fossil record.
State the information that relative dating and
radioactive dating provide about fossils
Identify the divisions of the geologic time scale.
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________ are scientist
who study fossils.
They infer what past
life forms were like.
They also classify
______ organisms.
Nest of dinosaur eggs.
They group similar
organisms and arrange
them in ____ in which
they lived.
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The ______ ______ provides
evidence about the history of
life on Earth. It also shows
how different groups of
organism, including species,
have changed over time.
______ occur in particular
order.
Some fossils only appear in ____ rock and others
appear in more _______ rock.
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The fossil record shows that ____of all species
that have ever lived on Earth are _______.
_______ means the species die out.
Fossils can be large, _______ preserved animals
or they can be as tiny as a _______ of a jaw bone.
Most fossils are formed in __________ rock.
________ rock is formed when exposure to rain,
_____, wind, and ____ breaks down rock into
smaller particles of sand, _____, and clay.
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As these particles sink to the bottom of a body of
_____, dead organism also sink to the bottom
and get _______ up.
_______ dating: the age of the fossil is
determined by comparing its _________ with
that of fossils in other layers of rock.
An _____ fossil is used to compare relative age.
To be an index fossil it must have had a wide
_________ _____ and existed only for a short
period of time.
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Relative dating allows paleontologists to
________ a fossil’s age compared with that of
other fossils.
___________ dating is the use of half-lives to
determine the age of a sample.
A __________ is the length of time required for
half of the radioactive ______ in a sample to
______.
_______-14 is useful for dating fossils younger
than _________ years old.
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To date older rocks, researchers use elements
with longer half-lives.
_____ decays to the inert gas ______ and has a
half-life of 1.26 billion years.
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Paleontologist use
divisions of the _______
time scale to represent
evolutionary time.
Geologic time begins
with the __________
Time.
After the Precambrian
Time, the basic divisions
of the geologic time scale
are ____ and _________.
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Geologists divide the time between the
Precambrian and present into ______ eras.
In the ________ many vertebrates and
invertebrates lived during this time.
In the ______ is the Age of the ________,
mammals also started evolving.
The most recent era is the Cenozoic called the
Age of _________ because mammals were
common at this time.
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Eras are subdivide into ________.
Look back to slide 8
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EARTH’S EARLY HISTORY
OBJECTIVES: 17.2
Describe how conditions on early Earth were
different form conditions today.
Explain what Miller an Urey’s experiments
showed.
State the hypotheses that have been proposed fo
how life first arose on Earth.
Identify some of the main evolutionary steps in
the early evolution of life.
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Geologic evidence shows that Earth is about __
billion years old.
When the Earth was struck by objects as big as
_____, it melted.
When the Earth melted, its _______ rearranged
themselves according to density.
These element ultimately cooled to form a solid
______.
The less dense elements (H,N) formed the first
_________.
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Earth’s early atmosphere probably contained
________ _________, carbon ______, carbon
monoxide, nitrogen, _______ sulfide, and water.
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______ and _____
experiments
suggested how
mixtures of the
organic compounds
necessary for life
could have arisen
from simpler
compounds present
on a primitive
Earth.
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Under certain conditions, large organic
molecules can for tiny bubbles called ________
___________.
Microspheres are not
cells, but they have some
characteristics of _____
systems.
They have selectively
________ membranes and
can store and ______
energy
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_________ are single-celled prokaryotic
organism that resemble modern bacteria have
been found in rocks more than _______.
Photosynthetic ______ became
common in the shallow seas of the
Precambrian.
The rise of ________ in the
atmosphere drove some life forms
to extinction, while other life
forms evolved new, more efficient
metabolic pathways that used
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oxygen for respiration.
According to the ______________ theory,
eukaryotic cells formed a symbiosis among
several different prokaryotic organisms.
Some time after eukaryotic cells arose, those
cells began to reproduce _______.
This enabled evolution to take place at a far
greater speeds than ever before.
A few hundred million years after the evolution
of sexual reproduction, evolving life forms
crossed over another great threshold: the
development of ___________ organisms.
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EVOLUTION OF MULTICELLULAR LIFE
OBJECTIVE: 17.3
Describe the key forms of life in the Paleozoic,
Mesozoic, and Cenozoic eras.
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______ percent of the Earth’s history occurred in
the Precambrian.
Rich fossil evidence shows that early in the
Paleozoic Era, there was a diversity of _____ life.
The _________ Explosion occurred during the early
Cambrian period.
The first known representatives of most animal
______ evolved.
Invertebrates, _________, and trilobites were
common
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Jellyfish
Trilobite (arthropods)
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During the _________ and _______ periods, the
ancestors of the modern octopi, squid, and
jawless fish appeared.
Jawless fish
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Forerunner of squid and octopi
By the ________ Period, some plants like ferns,
had adapted to drier areas, allowing them to
invade more habitats.
___________ (insects) appeared on land.
The Devonian Period is often called the Age of
______, even though the invertebrates were
more numerous.
Most of the fish of this time had ____, a ____
skeleton, and ______ on their body.
________ appeared in the late Devonian.
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Devonian fishes
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During the Devonian, ________ began to invade
the land.
The first fishes to
develop the ability to
______ awkwardly
on leglike fins were
fully aquatic
organisms.
Some evolved into the first _____________
(lives part of its life on land and part of its life in
water).
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Throughout the rest of the _______ Era, life
expanded over Earth’s continents (reptiles, huge
dragonflies, cockroaches, giant ferns).
The remains of those ancient plants formed thick
deposits of sediment that changed into _____.
This is one artist
depiction of the
__________ Period.
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At the end of the Paleozoic, many ________
died out.
This was a _____ extinction, in which many
types of living thing became extinct at the same
time.
The mass extinction at the end of Paleozoic
affected both _____ and ______ on land and in
the seas.
As much as ____of the complex life in the ocean
disappeared (trilobites).
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Events during the _______ include the
increasing dominance of dinosaurs.
The Mesozoic is marked by the appearance of
_________ plants.
Those organism that survived the extinction in
the _______, became the main forms of life early
in the _______ Period.
Mesozoic is often called the Age of _______.
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__________, was a
meat eater that light
hollow bones and ran
swiftly on its hind
legs.
_______ also
appeared during the
Triassic Period.
Mammal were very
______.
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During the ______ Period dinosaurs became the
dominant animals on land.
__________, was
one of the larger
dinosaurs of the
that period.
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_____________, was one of the first birds.
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Reptiles were still the dominant vertebrates
throughout the ________ Period.
Dinosaurs such as
the meat eating
_____dominated
land ecosystems
while flying
reptiles and birds
soar in the air.
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The Cretaceous also brought new forms of life,
including _____ trees, shrubs and small
flowering plants that produce ______ in fruit.
At the close of the Cretaceous, another ____
extinction occurred.
More than ____ of all plant and animal groups
were wiped out including the _________.
During the Cenozoic Era, mammals evolved
__________ that allowed them to live in various
environments – on land, in water, and in the air.
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The Cenozoic is often called the age of ________.
During the _______ Period the climate was warm
and mild.
_____ and dolphins
evolved.
On land flowering
plants and ______
flourished.
______ evolved which
encouraged grazing
animals
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During the _______ Period the land masses have
reach to about where they are today.
The climate was cool, causing a series of ___ ____.
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The fossil
record suggests
that the early
______ of our
species appeared
about ___ mya.
According to one _______,
members of our species began a
series of migrations from Africa
that ultimately colonized the
world.
The first fossils
assigned to our
own species
,___ ______,
appeared
200,000 ya.
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PATTERNS OF EVOLUTION
OBJECTIVE: 17.4
Identify important patterns of macroevolution.
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Biologists use the term __________ to refer to
large-scale evolutionary patterns and processes
that occur over long periods of time.
More than 99% of all species that have ever
lived are now extinct.
Several times in Earth’s history, mass extinctions
wiped out entire ecosystems.
Two reasons for extinction: ______ impact, or
____ activity at the end of the Cretaceous Period.
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Each disappearance left _________ open and
provided ecological opportunities for those
organisms that survived.
The extinction cleared the way for modern
_______ and birds.
_______ _______ is when 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
(Darwin’s _______).
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Darwin’s finches
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________ evolution is the process by which
unrelated organisms resemble each other.
dolphins
Great white shark
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__________ is the process by which two species
evolve in response to changes in each other.
________ equilibrium is when there is rapid
evolution after long periods of equilibrium.
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