History of Life and the
Origin of Species
Mrs. Stewart
Honors biology
Central Magnet School
Standards:
 CLE 3210.5.3 – Explain how genetic variation in a
population and changing environmental conditions
are associated with adaptation and the emergence of
new species.
Objectives (today, I will…)
 Differentiate between biogenesis and
spontaneous generation
 Differentiate between Charles Darwin
and Jean-Baptiste Lamarck
 Explain the idea of “natural selection”
and determine “fittest”
History of Life
 Biogenesis:
 All living things come from other living
things
 Spontaneous Generation:
 Living things could arise from nonliving
things
Redi’s experiment
 Previous idea: Flies were created from
rotten meat
 Redi: Meat kept away from adult flies
would not produce maggots
Spallanzani & Pasteur
 Spallanzani – tried to disprove that
microorganisms arose from a “vital
force” in the air
 Pasteur – improved spallanzani’s
experiment to eliminate the flaw of “no
air”
Ch. 15.1 – 15.2
History of
Evolution
Mrs. Stewart
Honors Biology
Central Magnet School
What is Evolution?
 Dictionary:
 The gradual development of something; especially
from a simple to complex form.
 Text book:
 Generally, in biology, the process of change by
which new species develop from pre-existing
species over time
 Evolution of Dance
th
18
Century Ideas
 About living species:
All species were permanent and unchanging.
 About the Earth:
Earth was only a few thousand years old and unchanging.
 Uniformitarianism
Idea by Charles Lyell that said geologic processes
happed slowly over time and that some features of
the Earth may take millions of years to form.
Jean-Baptiste Lamarck
 French Naturalist
 1809
 Lamarck’s Hypothesis: by selective use or disuse of
organs, organisms acquire or lose certain traits.
These traits could then be passed on to their
offspring.
 Lamarck believed over time, this process led to
change in a species.
Lamarck’s Hypothesis
1. Tendency toward perfection - All organisms
have an innate tendency toward complexity and
perfection, so they are continually changing to be
more successful in their environment
2. Use and disuse - Organisms can alter their
bodies/organs by use or disuse
3. Inheritance of acquired traits - Organisms can
pass on those altered body parts/organs to the
offspring
Lamarck the Loser
 First to develop a hypothesis of
evolution
 First to realize organisms adapt to their
environment
 But, Behavior has no effect on
inheritable characteristics
Charles Darwin
 1809 – 1882
 Naturalist – study of nature
and the natural world
 Sailed on the HMS Beagle in
1831
 Every time the ship docked,
Darwin went ashore to
collect plant and animal
specimens
 Darwin’s observations piqued his interest in
the diversity of life he observed.
 Darwin even found evidence that suggested
species once present on earth had vanished.
 Researchers today speculate that 99.9% of all
species that ever inhabited earth are now
extinct.
Galapagos Islands
 The islands were close together, but had very
different climates
 Smallest and lowest islands = hot, dry &
barren
 Hood Island = sparse vegetation
 Higher islands had greater rainfall and a
different assortment of plants/animals
 Isabella Island = rich vegetation
 Land Tortoise shell shapes could be used to
identify which island it inhabited
Pinta Island Tortoise
What
observations can
YOU make about
these species of
land tortoise?
Hood Island Tortoise
Isabella Island Tortoise
Pinta Island Tortoise
Which island
would you
predict has only
low-lying
vegetation?
Hood Island Tortoise
Isabella Island Tortoise
Darwin’s Idea
 Darwin observed that the plants and
animals varied noticeably among the
different Galapagos Islands.
 However, Darwin wondered if animals
living on different islands had once
been members of the same species –
originating from the same South
American ancestor
Darwin’s Finches
 Darwin observed many different types of
“finch” and noticed several different beak
shapes.
 Why?
 He began to notice different shaped beaks
were “adaptations” for different food
sources
Religion’s Role
 Darwin was a devout Catholic
 He knew that his ideas, based on what he observed
would provoke the catholic church
 He debated over what to do for 25 years.
Descent With Modification
 The Origin of Species by Means of
Natural Selection – 1858
 Every species – living or extinct –
descended by reproduction from
preexisting species
 AND
 Species must be able to change over
time
Natural Selection
Mrs. Stewart
Honors biology
Central Magnet School
Review
 What was Lamarck’s hypothesis?
Inheritance of acquired traits
 What did Darwin believe?
Species changed as environment changed – adaptation
and survival of the fittest
Standards:
 CLE 3210.5.3 – Explain how genetic variation in a
population and changing environmental conditions
are associated with adaptation and the emergence of
new species.
Darwin’s reasoning for
Natural Selection
1. Overproduction – more offspring produced than can
survive
2. Genetic Variation – within a population, individuals
have different traits. New traits may appear
spontaneously.
3. Struggle to survive – constant competition may cause
some variations/traits to be advantageous
4. Differential Reproduction – Organisms with the best
adaptations will survive and reproduce, thus the
advantageous adaptations will become most prevelant
in the population.
Evolution by Natural
Selection
 Struggle for existence – each member
of a species competes regularly for
food, living space and other necessities
of life.
 main needs: Food, water, living
space and ability to reproduce
 Who wins?
Survival of the Fittest
 How well suited an organism is to it’s environment
 Does fittest mean strongest?
 Does fittest mean in the best shape?
 Fitness – the ability of an individual to survive and
reproduce
 The result of adaptations
Survival of the Fittest
 Fittest – the individuals most capable to survive
and reproduce for multiple generations
 The traits selected as the most useful for
survival and reproduction are determined by
the organisms environment
 Natural Selection accounts for Descent with
Modification as species become better adapted
to different environments.
Adaptation vs.
Acclimatization
 Adaptation - Changes in traits in populations
over time
 Example: White moth population becoming
a black moth population after 5 generations.
 Acclimatization – individual organism
changes physiologically
 Example: growing thicker fur in winter
Adaptations
 Any inherited characteristic that increases an
organism’s ability to survive and reproduce
 Anatomical or structural characteristics
 Porcupine quills - protection
 Longer necks in giraffes – find food
 Physiological processes
 How a plant performs photosynthesis
 Instinctual Behaviors
 Hunting in packs
 Living in burrows
Objectives (today, I will…)
 Differentiate between biogenesis and
spontaneous generation
 Differentiate between Charles Darwin
and Jean-Baptiste Lamarck
 Explain the idea of “natural selection”
and determine “fittest”
Evidence of Evolution
Mrs. Stewart
Honors Biology
Central Magnet School
Standards:
 CLE 3210.5.3 – Explain how genetic variation in a
population and changing environmental conditions
are associated with adaptation and the emergence of
new species.
Descent with Modification
 Over long periods of time, natural selection
produces organisms with different structures,
niches or occupy different habitats than their
ancestors.
 Each living species has descended, with
changes, from other species over time.
 Result: species today look/act different from
their ancestors
Common Descent
 Look back: Tigers, panthers and cheetahs all
share a common ancestor
 Look back further: you will find ancestors that
these cats share with horses, dogs and bats.
 Farther back: common ancestors of mammals,
birds, alligators and fishes.
 Logic: looking far enough back we should find
the common ancestor for all living things
Common Descent
Homologous
Structures &
Vestigial Organs
Fossil
Records
Evidence
of
Evolution
Common
Descent &
Descent w/
Modifications
Comparative
Embryology
Fossil Records
Fossils - preserved
remains of ancient
organisms
Compare
fossils from
older layers
and
younger
layers and
show
changes in
species over
time
Fossil Records
 Compare fossils found around the world and we
can infer when and where different organisms
existed.
 Fossils also provide evidence about the
environment in which the organism existed and for
which the organism adapted
Transitional
Species
 Fossil records
show species
which have
features that are
intermediate
between those of
hypothesized
ancestors and
later descendant
species
Homologous Body Structures
Homologous Body
Structures
 The limbs of reptiles, birds and mammals
(arms, wings, legs and flippers) vary greatly
in form and function but are all constructed
from the same basic bones.
 Vestigial Organs – organs/body parts that
were once used, but by natural or artificial
selection, are no longer necessary
Appendix
Vestigial Organs
Vestigial Organs
Hip bone in a whale
Tailbone in humans
Vestigial Organs
Similarities in Embryology
 The early stages, or embryos, of many
animals with backbones are very similar.
 Does this mean that a human embryo is ever
identical to a fish, or a bird embryo?
 NO
 But, many embryos look especially similar
during early stages of development.
Fish
Salamander
Tortoise
Chicken
Pig
Man
Comparative Embryology
 What do these similarities mean?
 The same groups of embryonic cells develop in the
same order and in similar patterns to produce the
tissues and organs of all vertebrates.
Exit Ticket: Socrative.com
Room Number: Stewart 348
Question: How does the environment
determine the “fittest” individual?