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Lamarck – French naturalist in the early 1800’s; came up
with the idea that organisms acquire or loose traits by either using
or not-using them. He was the first to recognize that organisms are
adapted to the environment in which they live.
(Characteristics arise as needed) = Wrong!!
Lamarck believed that giraffes obtained a
long neck by constantly stretching to reach
the leaves of tall trees.
Lamarck thought that the
repeated use of a claw
would cause it to grow
larger!!
Evolution - change in a species over time
Evolution is a theory suggested by
Charles Darwin
______
______.
Theory -
hypothesis that has been
a ___________
tested
__________
many times, and is
accepted by scientists
_________
Theories help
scientists make
__________
predictions
about the natural
world.
What if I could
breathe air?
The basic idea:
An individual may be born with a
mutation that gives it an
_________
adaptation and helps it to _______.
__________
survive
Adaptation - a trait that improves the chance of
survival and reproduction in an organism
This organism will eventually ________
reproduce
and the __________
adaptation will be passed on to
its ________.
offspring
You mean…
I would be
eaten?!?!
Over time, beneficial
________ traits
_____ tend to
more _______,
common and _______
harmful
become ____
traits tend to become ____
_____
less _______.
common
SPECIES evolve NOT
__________
________________
INDIVIDUALS .
SPECIES evolve over _______.
TIME
_________
I’m walking
upright!
But you still
have a tail.
Darwin’s Theory (6 main points):
1) Overproduction - Species produce
more offspring than
what is needed for
the population (most
die, best traits
survive)
2) Competition competition among organisms helps
SELECT the best adapted
individuals to survive
Examples:
For food / shelter / territory / females
Lions
Same
situation as
the elephant
seal
3) Survival of the Fittest organisms with the best adaptations
will have a better chance at survival
4) Natural Selection only some individuals of a population
will survive to produce offspring
(environment (nature) selects)
5) Variation – (differences)
some variations make an organism
better adapted for survival
(variation is helpful to a population)
Neither can fly, but…..
6) Speciation –
when variation between organisms
become so great that new species
develop
Fossil Forming
Water carries small
rock particles to lakes
and seas.
Dead organisms are
buried by layers of
sediment, which forms
new rock.
The preserved
remains may later be
discovered and
studied.
1) Fossils – found in sedimentary
rock
Layers of sediment
form layers of rock
When part of
Earth’s crust is
compressed, the
layers bend
Erosion allows
new layers to be
visible
New sediment
can form over
the old rock
a)
newest
b)
newer fossils
c)
older fossils
d)
oldest
2) Comparative anatomy – structures
in different organisms look similar.
human
whale
bat
These are known as homologous
structures. Ex: to hold, swim or fly.
Turtle
Alligator
Bird
Mammal
Ancient fish
Organisms formed these appendages
from a common ancestor
Similar bone
structures are
found when
comparing
humans with
gorillas
Single-Loop
Circulatory System
FISHES
Double-Loop Circulatory System
MOST REPTILES
CROCODILIANS,
BIRDS,
AND MAMMALS
Similar respiratory systems in
animal species
Large brow
ridge
Large nose
Large canine
teeth
Face protrudes
forward
Australopithecus afarensis
Weak brow
ridge
Homo erectus
Large
brain
case
Round, high
skull
Inflated
cheeks
Large
nose
Even teeth
Strong chin
Neanderthal
Cro-Magnon
Modern Homo sapiens
Similarities in skull shape of prehistoric man
Pinta
Pinta Island
Intermediate
shell
Fernandina
Tower
Marchena
James
Santa Cruz
Isabela
Santa Fe
Floreana
Isabela Island
Dome-shaped shell
Hood
Hood Island
Saddle-backed
shell
Natural selection –
different environments on
different islands selected
the best adapted shell
shape
Pinta island
Hood island
Isabella island
Beaver
Environmental
differences in
where these
mammals live
allows different
adaptations to
be successful
Beaver
NORTH
AMERICA
Muskrat
Muskrat
Beaver and
Muskrat
Coypu
Capybara
Capybara
SOUTH AMERICA
Coypu
Coypu and
Capybara
3) Comparative Biochemistry
All organisms contain DNA.
Many organisms make similar proteins.
4) Comparative Cytology
Living things are made of cells.
Most cells have similar organelles.
Comparative Cytology
Chloroplast
Aerobic
bacteria
Ancient Prokaryotes
Nuclear
envelope
evolving
Photosynthetic
bacteria
Mitochondrion
Plants and
plantlike
protists
Primitive Photosynthetic
Eukaryote
Ancient Anaerobic
Prokaryote
Primitive Aerobic
Eukaryote
Animals, fungi, and
non-plantlike
protists
5) Comparative Embryology –
Living things show signs of similar
early development of different
animals, they all look extremely
similar as embryos.
Comparative Embryology
Amnion
The amnion is a fluid-filled sac
that surrounds and cushions
the developing embryo. It
produces a protected, watery
environment.
Allantois
The allantois stores the
waste produced by the
embryo. It also serves
as a respiratory organ.
Embryo
Chorion
The chorion regulates
the transport of
oxygen from the
surface of the egg
to the embryo and
the transport of
carbon dioxide,
one product of
respiration, in the
opposite direction.
Yolk sac
This baglike structure
contains a yolk that
serves as a nutrient-rich
food supply for the
embryo.
Shell
Convergent Evolution
Nine-Banded
Armadillo
Chinese
Pangolin
Common
Echidna
Giant Anteater
Aardvark
Even though they evolved separately, they look alike because
they eat the same food (insects).
The environment selected for a long nose and sticky tongue.
How Would You Classify These Four
Organisms into Two (2) Groups?
barnacle
crab
limpet
Legs
Crab
Circular shells
Barnacle
Limpet
Crustaceans
Crab
Mollusk
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimmin
CLASSIFICATION BASED
ON VISIBLE
SIMILARITIES
CLASSIFICATION
BASED ON GENETIC
SIMILARITIES
Legs
Crab
Circular shells
Barnacle
Limpet
Crustaceans
Crab
Mollusk
Limpet
Barnacle
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION BASED
ON VISIBLE SIMILARITIES
CLASSIFICATION
BASED ON
GENETIC
SIMILARITIES
DOMAIN
ARCHAEA
DOMAIN
EUKARYA
Kingdoms
DOMAIN
BACTERIA
Eubacteria
Archaebacteria
Protista
Plantae
Fungi
Animalia
Sources of Variations
1) Mutations - Random changes in
DNA that help to
increase variation
(differences) in a
population
For a mutation to be passed on, it
must occur in the sex cells (gametes).
Most
mutations are
harmful.
2) Sexual reproduction/
Recombination
because the genes of 2 parents
are combined, offspring are
created with more genetic
variation
Because of the
combination of
sperm and egg, the
offspring will have
genes from each
parent organism.
3) Crossing Over process during meiosis
where genes on
chromosomes are
swapped to create
gametes that are
different from each
other
Remember: When crossing over, paired
chromosomes will exchange genes at
random, creating different combinations.
Crossing over occurs during the first cell
division in meiosis, where homologous
chromosomes swap chromosomes whole
creating sperm or egg cells.
Adaptation any characteristic that increases an
organism’s chance of survival or
reproduction
Three Types
of Adaptations
1) Structural change physical change
example:
Polar bears
have thick and
hollow fur for
warmth!
1) Structural change - physical
change
example: Giraffes have long necks
to reach tall trees
2) Functional change -
molecular changes that affect how
structures work
example:
The cells on
jellyfish
tenticles can now
sting!
3) Behavioral change example:
Ducks fly
south for
the
winter.
how organisms act!