Species Change Over Time
Lamarck
Darwin
Who thought this?
 There is VARIATION within a
species

DARWIN
 Organisms can make a change to
themselves and pass that onto
their offspring
 LAMARCK
 Acquired Characteristics

LAMARCK
 Organisms change over time.

BOTH
 Species cannot go extinct
 Change within a population, not
an individual
 DARWIN
 Natural Selection

DARWIN

Lamarck
 Whose idea is still believed by the
scientific community today
 Darwin
Adaptations Over Time
Chapter 12 Pages 334-341
Review of Important Terms to
Know
 Traits-characteristics of a
species that are passed from
parent to offspring.
 Offspring- the scientific
name for “babies” of an
organism
Species
 Species- a group
similar organisms that
can mate with each
other and produce
fertile offspring
~8.7 Million Species
Worldwide!
 Fertile- the ability to
reproduce
 Animals: 7.77 million
 Fungi: 0.61 million
 Plants: 0.30 million
 Protozoa: 0.04 million
 Chromists: 0.03 million
Variation
 Variation- any inherited
difference between
members of the same
species
 Ex: albino squirrel, the ability
for baby turtles to swim faster,
a longer neck, wider nostrils,
thicker fur…
Forsten’s Tortoise
What Causes Variation?
 SEXUAL REPRODUCTION
 Variations result from
permanent changes in an
organism’s genes.
 The permanent changes in
the genes are called
MUTATIONS.
American Alligator with a
pigment mutation
Mutations…Good or Bad???
 Mutations can be either
beneficial, harmful or
neutral.
 Some gene changes
produce LARGE variations.
 Ex: Albino squirrel
 Some gene changes
produce small variations
 Ex: shape of human hairlines

“People don't realize it, but everyone has
about 60 genetic mutations in their body
at any given time. (Tudge, Colin)”
King Cheetah Pattern
Mutation
 “A genetic mutation changes
a spotted cheetah pattern to
a striped king cheetah
pattern.”
Adaptation
 Adaptation- a variation (or
trait) that helps an organism
survive & reproduce
 Adaptations can be
behavioral or physical.
Adaptations
BEHAVIORAL
 The way an organism acts or
PHYSICAL
 Body structures
behaves




Migration
Hibernation
Communication
Mating dances







Camouflage
Shapes of beaks
Fur
Blubber
Color or Markings
Webbed-feet
Body coverings
4 Principles of Natural
Selection
Darwin’s Theory of Natural
Selection
 Natural Selection- individuals
that are better adapted to
their environment are more
likely to survive &
reproduce than other
members of the same
species
 Also known as “Survival of
the Fittest”
Overproduction
 1) Overproductionproducing more offspring
than can survive
Overproduction
Competition
 2) Competitionindividuals compete for
food, nesting sites,
territory, & other
resources that affect
their ability to reproduce
Variation
 3) Variations- a difference
between members of
same species that may
help it survive and
reproduce
 Some are born with an
advantage over the
others!
 Ex: beak shape, eyesight,
height, speed…
Selection
 4) Selection- over time, the
environment “selects”
organisms w/ helpful traits to
be parents of next generation
 Ex: Just as the changing
forest affected the peppered
moths.
WRAP UP
.
 Over a long period of time, natural selection can lead to
the evolving of a new species. Helpful variations
remain & unfavorable ones disappear
Factors that Affect Natural
Selection
 1) Overproduction- producing
more offspring than can
survive
 3) Variations- a difference
between members of same
species that may help it
survive
 2) Competition- offspring
compete for food & other
resources
 4) Selection- over time, the
environment “selects”
organisms w/ helpful traits to
be parents of next generation
Do Now: Bear Trio!
 In your journal answer the
following questions.
 What differences do you
notice among the three
bears?
 What did Darwin call these
differences?
 What causes these
differences among
organisms?
Line Graphs
 Which day were the most
cookies sold?
 What is the title of graph?
 What day were 20 cookies
sold?
 About how many cookies
were sold on Tuesday?