Download Evolution ppt.

Bell Ringer:
How does this
picture relate to the
theory of evolution
and natural
selection?
What current or past
evidences support
the theory of
evolution?
1. The students will be able to define fossil and explain how
scientists find the age of a fossil.
2. The students will be able to explain how fossils provide
evidence of evolution.
Fossil – the remains or evidence of a once living organism that can
consist of hard or soft parts; fossils can be impressions or original tissues!
remains – bones, teeth, shells, soft tissue impressions
(skin, muscles, leaves, feathers)
evidence – trace fossils (tracks or trails)
Fossils can form in a variety of ways:
carbonization
mineralization
mold and cast
trace fossils
The fossil record is made up of all
the fossils ever discovered on Earth
and the record is incomplete!
The fossil record provides evidence
that species have changed over time.
http://www.ucmp.berkeley.edu/fosrec/
Paleontologists (geologists who specialize in studying the fossil record) can
determine the age of a fossil through Relative Age Dating or Absolute Age Dating
Relative Age Dating – geologists determine the relative order in
which the rock layers were deposited using terms like “oldest” or
“youngest”.
Rock layer “A” is the
youngest layer.
Rock layer “D” is the
oldest layer.
Rock layer “B” is older
than rock layer “A” but
younger than rock layer
“C”.
What can you say about the
relative age of the fossils
found in layer “3”?
What can you say about the
relative age of the fossils
found in layer “3”?
The fossils in layer 3 are
older than the fossils in
layer 4 but younger than
the fossils in layer 2
Which is the oldest layer?
Which is the youngest layer?
Is layer “P” older or younger than
layer “M”?
What happened first?
Layers “L” through “Q” were tilted
OR
Layer “H” was deposited
Which is the oldest layer?
Layer Q
Which is the youngest layer?
Layer K
Is layer “P” older or younger than
layer “M”?
Layer P is younger than M
What happened first?
Layers “L” through “Q” were tilted
OR
Layer “H” was deposited
Layers L through Q were tilted
Absolute Age Dating – allows Paleontologists to provide an age date
for fossils using “radioactive decay”
• Over time, unstable (parent)
elements in rocks change into
stable (daughter) elements
• Scientists measure the ratio of
unstable to stable elements to
obtain an age
• For example, within 1 half-life/ 5,730
years, half of Carbon 14 atoms
(parent) have decayed into
Nitrogen 14 (daughter)
http://pubs.usgs.gov/gip/fossils/numeric.html
•To age date the fossils, it is
easiest to use the igneous
rock layers above and
below the fossiliferous
sedimentary rock layer
because igneous rocks
contain chemical elements
which spontaneously decay
http://evolution.berkeley.edu/evosite/lines/IIIAchronology.shtml
The Geologic Time Scale is a chart that divides the Earth’s history into
different time units; it was compiled using both types of age dating
species – lowest level of classification; individuals resemble each other
and can mate with each other but not with members of another
species
extinction – a species is extinct when the last individual of the species dies
The fossil record contains evidence of
extinctions. Sudden disappearances of
fossils in rock layers are evidence of
extinction.
What causes extinction?
1. Sudden environmental changes –
volcanic eruption, meteorite impact
2. Gradual environmental changes –
plate tectonic movements can cause
the development of mountain
ranges or ocean basins which isolate
the species from its resources
1. Ordovician (440 mya) -- extinction of
benthic faunas including trilobites,
graptolites, and conodonts.
2. Devonian (365 mya) -- decimation of coral
reefs and brachiopods
3. Permian (250 mya) -- estimated 96%
extinctions at species level in the marine
realm; reduction in terrestrial tetrapods
4. Triassic (210 mya) -- extinctions wiped out
23% of both marine and non-marine animal
families, including sponges, gastropods,
bivalves, cephalopods, brachiopods,
insects, and vertebrates.
5. Cretaceous (65 mya) -- the extinction of all
non-avian dinosaurs, plus substantial to
complete losses among such diverse
groups as ammonites, rudists, and certain
marine reptiles.
http://www.amnh.org/science/biodiversity/extinction/Intro/OngoingProcess.html
Paleontologists use fossils as
evidence that species have changed
over time.
Newer layers of rock show organisms that are
more similar to modern day organisms than do
older rock layers
WHALE EVOLUTION
Biological Evolution is the change
over time in populations of related
organisms.
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html
http://evolution.berkeley.edu/evosite/evo1
01/VIIAPaceevolution.shtml
Fossils are the remains or evidence of once living organisms and form in many ways
(carbonization, mineralization, mold and cast)
Scientists can learn the ages of fossils by using the techniques of relative age dating
and absolute age dating
Though incomplete, the fossil record provides evidence that living things are related
and species have changed over time (biological evolution of related species)
http://www.dep.state.fl.us/geology/geologictopics/fossil.htm
http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html
http://www.news.wisc.edu/15320
Common ancestor – two or
more species evolved from one
species that lived in the past
Species that share a recent
common ancestor have similar
DNA
http://palaeo.gly.bris.ac.uk/palaeofiles/whales/archaeoceti.htm
Cladograms are diagrams that show the evolutionary relationships
between species of organisms
Approximately when did the whales and hippopotamuses diverge from a common
ancestor? Are hoofed mammals more closely related to hippos or camels?
http://www.amnh.org/ology/features/treeoflife/pages/howtoreadclado.php
1. The students will be able to explain the theory of
evolution by natural selection
2. The students will be able to relate genetic variation
and environmental factors to adaptations and
extinctions
Charles Darwin was a naturalist who voyaged around the
world on the British naval ship called the HMS Beagle
Darwin made many observations
of the different environments
and different species of flora and
fauna that he saw (1831 – 1836)
Darwin knew that members of a
species could exhibit variations
(slight differences in an inherited
trait)
variations are caused by random
mutations/changes in genes;
these changes are passed on to
future generations (Darwin did
not know about genes)
What is Natural Selection?
the process by which populations of organisms, with variations that help them
survive in their environments, live longer, compete better, and reproduce more
than those that do not have the variations
THE FOUR PARTS TO NATURAL SELECTION:
1. Reproduction – a population produces offspring with
inherited traits
2. Variation – some of the offspring may have a variation
making them more suitable to their environment
3. Competition – due to limited resources, not all of the
offspring will survive; offspring with the beneficial
variation survive and reproduce
4. Selection – over time, the variation is inherited by more
and more offspring until eventually the entire population
has the variation and the species changes
http://evolution.berkeley.edu/evolibrary/search/imagedetail.php?id=316&topic_id=&keywords=
http://evolution.berkeley.edu/evosite/misconceps/IDtrying.shtml
Adaptation – an inherited trait that increases an organism’s chance of
surviving and reproducing in its environment
Adaptations can be
1. Structural – color, shape (camouflage)
2. Behavioral – the way an organism behaves or acts (hunting at
night)
3. Functional – changes to the internal system of an organism (a
drop in body temperature during hibernation)
Camouflage – an
adaptation that
allows a species to
blend in with its
environment
Mimicry – an
adaptation that
allows one species
to resemble
another species
herding
nocturnal
toxins
hibernation
Artificial Selection - Instead of nature selecting variations, humans
are selecting variations!
Selective Breeding – the breeding of organisms for desired
characteristics (domestic plants and animals are selectively breed)
http://www.physorg.com/news4301.html
The 19th century naturalist, Charles Darwin, developed his theory of evolution
by natural selection that is still studied today
Darwin’s theory of evolution by natural selection is the process by which
populations with variations that help them survive in their environments live
longer and reproduce more than those without beneficial variations
Over time, beneficial variations spread through a population and new species
that are adapted to their environments survive
Camouflage, mimicry, and other adaptations are evidence of the close
relationships between species and their changing environments
1. The students will be able to identify and/or explain ways
in which fossil evidence is consistent with the scientific
theory of evolution
Since Charles Darwin published his theory of evolution by natural selection,
scientists have confirmed, refined, and extended Darwin’s work
Living species that are closely related share a close common ancestor
Evidence for evolution and relatedness through a common ancestor
among living and extinct species comes from the study of:
fossils
comparative anatomy
developmental biology/embryology
molecular biology
Fossils are the remains of once living organisms and
provide evidence of evolution and the change in
species over time
Comparative Anatomy – the study of the similarities and differences among the
structures (body parts/forms) of living species
1. Homologous Structures – body parts of organisms that are similar in
structure (form) and position, but different in function (job)
whale
human
lizard
bird
http://evolution.berkeley.edu/evolibrary/article/0_0_0/similarity_ms_03
All 4 organisms inherited these structures from a common ancestor
2. Analogous Structures – body parts of organisms that are similar in
function (job), but different in structure (f0rm)
3. Vestigial Structures –parts that have lost their original function through
evolution
whales have tiny pelvic bones inside their bodies
humans have an appendix that has no function
dandelion plant has a stamen and a pistil but reproduces asexually
human tailbone (coccyx)
wings on flightless birds
Embryology – the science of studying
the development of embryos from
fertilization to birth
Example: pharyngeal pouches
All vertebrate embryos have pharyngeal
pouches at one stage in their development,
but the feature develops into different body
parts in different vertebrates (similarities in
function and location suggest an evolutionary
relationship)
humans, reptiles, birds – develops into a
neck gland that regulates calcium
fish – develops into the gills; one
function of gills is to regulate calcium
Molecular Biology – the study of gene structure and function
Charles Darwin did not know about genes, but today’s
scientists know that gene mutations are the source of variations
deletion
insertion
substitution
The more closely related two species are, the more similar their genes are.
NOTE: Not all fossils contain DNA!
The fossil record is incomplete! However, scientists discover new evidence
supporting the theory of evolution by natural selection all the time!
Tiktaalik
(lived 385 to 359 million years
ago)
Scientists think it is a transitional
species, or intermediate species,
a species that links
two other species.
It had fins with thin ray bones,
gills, and scales like a fish, but it
also had sturdy wrist bones and
thick ribs like a four-legged
vertebrate!
http://evolution.berkeley.edu/evolibrary/news/060501_tiktaalik
Fossils provide only one source of evidence of evolution. Additional evidence
comes from studying living species
By comparing the anatomy of organisms and looking for homologous or
analogous structures, scientists can determine if organisms had a common
ancestor
Some organisms have vestigial structures, suggesting that they descended from a
species that used the structure for a purpose
Scientists use evidence from
developmental and molecular biology
to help determine if organisms are
related
All of Earth’s organisms are related
through evolution by natural selection.
The more recently they share a common
ancestor, the more closely they are
related
A certain reptile species is a herbivore and exists only on an isolated island.
Which of the following would most likely result in the extinction of the
reptile species over a period of twenty thousand years?
A. The reptile species produces many offspring with many unique traits, and
the vegetation remains constant
B. The reptile species produces few offspring with some unique traits, and
the vegetation remains constant
C. The reptile species produces few offspring with no unique traits, and the
vegetation changes quickly
D. The reptile species produces many offspring with some unique traits, and
the vegetation changes slowly
Snakes have traces of leg-like structures that are not used for movement.
Which of the following could you infer from this evidence?
A.
B.
C.
D.
Snakes do not have ancestors.
Snakes are an example of transitional fossils.
Snakes share a common ancestor with animals that have legs.
Snakes and animals that have legs are part of the same species.
The fossil record contains fossils from many geologic ages. Fossils enable
scientists to piece together what ancient organisms looked like. Which of these
answers best describes how fossils in the fossil record are classified?
A.
B.
C.
D.
by ages and physical similarities
by whether the fossil contains hard or soft tissues
by size and the type of rock in which they are found
by similarities in their DNA and in the minerals they contain
Mr. Van listed the following four topics on the board.
1. relationships between extinct and living organisms
2. ancestors of living organisms
3. ways that groups of species are related
4. genetic similarities and differences between extinct and modern-day
species
For which of these topics does the fossil record provide evidence?
A. 1 only
B. 1 and 2
C. 1 , 2, and 3
D. 1, 2, 3, and 4
A scientist described two modern-day species as sharing a common ancestor.
What does it mean when two species share a common ancestor?
A. It means that the two species are actually the same species.
B. It means that one of the species evolved from other species.
C. It means that both species evolved from one species that lived in the
past.
D. It means that the two species share all the same traits.
The figure below shows two spotted
salamanders. They are the same species of
salamander, but they live in different areas.
Which of these terms is used to describe the
difference between them?
A. overpopulation
B. population
C. extinction
D. variation
The diagram below illustrates changes over time in a population of foxes in the
wild.
What process is illustrated in the diagram?
A. extinction
B. overproduction
C. natural selection
D. artificial selection
The diagram below shows the changes over time in a population of mice in the wild
after a population of hawks has moved into their environment. The white and dark
mice differ only in color.
Which statement is the most likely explanation for why the mouse population changed
over time?
A. The hawks eat more dark mice than white mice because the dark mice taste better.
B. The white mice are able to reproduce more successfully than the dark mice do.
C. The hawks eat more white mice than dark mice because they can see the white
mice more easily.
D. The hawks eat more dark mice than white mice, because they can see the dark mice
more easily.
Ronald observes a sparrow’s nest in a shrub outside his home. The table below
describes his findings.
Week
1
3
4
7
Observations
Six eggs were laid in the nest.
Five eggs hatched, and one egg did not hatch.
One of the chicks disappeared.
Three of the chicks learned to fly, and another one disappeared.
What part of natural selection did Ronald observe?
A. adaptation
B. overproduction
C. selection
D. variation
Within a population, variation increases the likelihood that some
individuals will be able to survive if the environment changes.
Which of the following causes variations within a population?
A.
B.
C.
D.
changes in extinction rates
changes in the genetic material
changes in the breeding rate
changes in the environment