Transcript evolution - Sewanhaka Central High School District

In your notes,
compare the two
pictures. List at
least three
similarities and at
least three
differences
The change
of a species
over time….
Millions
of years
Gene pool
the process of change
in the inherited traits
of a population of
organisms from one
generation to the next
Changes in structure,
function and behavior
Theory: An idea
which is supported
by extensive,
repeated
experiments, but
not proven as law.
Why isn’t evolution
a law?
Limited access to
the past
PRESENT DAY
SPECIES
DEVELOPED
(EVOLVED) FROM
EARLIER,
DISTINCTLY
DIFFERENT
SPECIES.
The “evolution” of
Evolutionary
Theories
Lamarck’s Theory:
Stated that
structures appear
because they are
needed,
called the theory of
Use & Disuse
ex. Longer necks in
giraffes
Weismann
DISPROVED the
theory that stated
that acquired traits
can be passed on to
the next
generation.
Charles Darwin
“The Father of
Evolution”
WHO WAS CHARLES DARWIN?
*GREW UP IN ENGLAND.
*LEFT MEDICAL SCHOOL AT 17 YEARS OLD
*BECAME A CLERGYMAN & NATURALIST AT
THE AGE OF 22.
*SAILED ON THE H.M.S. BEAGLE IN 1831.
*PUBLISHED THE ‘ORIGIN OF SPECIES’ IN
1859.
HOW DID DARWIN START?
GALAPAGOS ISLANDS
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NORTH
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AMERICA
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PACI FI C
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AFRI CA
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EQUATOR
OCEAN
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AMERICA
TROPICOF CAPRICORN
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TROPICOF CANCER
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OCEAN
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AN
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TROPOFCAPRICORN
AUSTRALIA
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ANTARCTICA80
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Darwin wrote about the
differences between the
European animals and plants
compared to their counterparts
in South America, Australia &
Africa.
These observations, and his
readings of other scientific novels,
led Darwin to doubt his religious
background about the origin of the
Earth.
Originally Darwin’s ideas were
referred to as………………
1859
wrote book titled
“Origin of the Species”
Key Concepts
1. Species present now
were not created in
present forms instead
they evolved from
ancestral species
2. Natural Selection:
causes evolution
States that only
those organisms
containing the best
variations can
survive and
reproduce in a
given environment
Individuals who
survive are the
ones best adapted to
exist in their
environment due to
the possession of
variations to
maximize their
fitness.
Overproduction
Competition
Variations
Adaptations
Survival of the Fittest
Natural Selection
Speciation
Formation of a
new species due to
favorable
adaptations
gradually
accumulating,
while unfavorable
adaptations
gradually
disappear
Any organisms
which can:
1. Interbreed
2. Produce
fertile
offspring
3. Under
natural
conditions
• Darwin observed 13 species of
finches on the Galápagos Islands
that were similar except for
differences in body size, beak
shape, and eating habits.
• He also noticed
that all finches
were similar to
1 finch he saw
on the South
American
coast.
• Darwin reasoned that the Galápagos
finches must have had to compete
for food.
• Finches with beak shapes that let
them eat food survived longer &
reproduced more than finches
without those beak shapes.
• After many generations, these
groups of finches became separate
species.
A person has been arrested on the
charge that he robbed $50,000 from
the First City National Bank last night.
What must the district attorney do to prove
that this man is the robber?
Evidence is essential for all scientific
studies, theories, and laws.
In science, the word
theory refers to a
comprehensive
explanation of an
important feature of
nature that is supported
by many facts gathered
over time.
In this sense, a
theory is a
systematic and
formalized
expression of all
previous
observations, and
is predictive,
logical, and
testable.
Evidence
In science …evidence is accumulated
through observations of phenomena
that occur in the natural world, or
which are created as experiments in a
laboratory.
Scientific evidence usually goes
towards supporting or rejecting a
hypothesis
Is the sum total of all the
fossils discovered and
undiscovered and their
placement in sedimentary
rock layers
Fossils are the mineralized or
otherwise preserved remains or traces
(such as footprints) of animals, plants,
and other organisms
TYPES OF
FOSSILS
Cast/mold fossils
the original remains of
the organism have been
completely dissolved or
otherwise destroyed
True form fossils …
remains of the actual
animal or animal part
Trace fossils
…….are the
remains of track
ways, burrows, eggs
and eggshells, nests,
droppings and other
types of
impressions.
RESIN FOSSILS …..
Resin is an excretion of
certain plants for
protection
When an organism gets
caught, whole
organism preservation
occurs
is the study of similarities and
differences in the anatomy of
organisms.
Structure and form
Homologous structures
•body parts which
are similar in
different species
•they may or may
not perform the
same function.
•An example is the
forelimb structure
shared by cats and
whales.
anatomy
whose bones are they?
HOMOLOGOUS
STRUCTURES are
evidence that a
common ancestor
exists for the
organisms being
studied
The leaves of an oak (left) and the leaves of a gingko (right) are
homologous — they were both inherited from a common ancestor
with leaves.
The wing of a dragonfly (left) and the wing of a
butterfly (right) are homologous — they were
both inherited from an ancient flying insect.
Analogous
Structures
•Structure that are
similar in different
organisms because they
evolved in a similar
environment
•They usually serve the
same or similar purposes
•An example is the
torpedo body shape of
porpoises and sharks
VESTIGIAL STRUCTURES
describes homologous traits of organisms
which have lost all or most of their original
function in a species through evolution
study of comparative
developmental anatomy
is the study of differences in chemical
(metabolic) processes among species
EXAMPLES
DNA AND
CHROMOSOMES
IS THE STUDY OF DIFFERENCES IN CELL
STRUCTURE, COMPOSTION AND
FUNCTION