Download Evolution - Mrs. Pam Stewart

Bell Work
 Pick up today’s note page
 Define evolution
Introduction to Evolution
and the Origin of Life
Mrs. Stewart
Biology
Stewarts Creek High School
Standards:
 CCSS ELA 9-10.2
 I can trace the historical development of the
theory of evolution
 I can summarize the evidence for the theory of
evolution
 CCSS ELA 9-10.8
 I can critique and evaluate competing
evolutionary arguments based on scientific
knowledge, empirical evidence and logical
arguments regarding relevant factors.
Can You…
 Define evolution
 Differentiate between biogenesis and
spontaneous generation
 Differentiate between Charles Darwin
and Jean-Baptiste Lamarck
 Explain the idea of “natural selection”
and determine “fittest”
Choose…
 But choose
wisely.
 Decide which
partner is the
bird and which
is the cat.
Scientific Theory
 Theory - a well-substantiated
explanation of some aspect of the
natural world, based on a body of facts
that have been repeatedly confirmed
through observation and experiment.
How did it all start?
 Abiogenesis:
 The process by which life arises from nonliving matter, such as organic compounds
 Happened on earth approx. 3.8 - 4.1 billion
years ago in the ocean
 Enough organic compounds bound together
and were able to conduct energy processes
more efficiently until life was created
Early Beliefs of How New
Life Formed
 Abiogenesis / Spontaneous Generation:
Living organisms could arise from nonliving
matter
 Example: Cheese wrapped in a rag and left
in a corner would produce mice
 Disproven by Redi and Pasteur
 Biogenesis:
 All living things come from other living
things
Miller/Urey
 Stanley Miller and Harold Urey (1950s)
 simulated early earth conditions in the
lab and created a “spark”
 created amino acids
 www.ucsd.tv/miller-urey/
Archaebacteria
 The earth’s
earliest life
forms were
prokaryotes
Endosymbiosis
 Where/how did mitochondria get their own DNA?
 How did chloroplasts become so specialized?
 Theory of Endosymbiosis:
 Aerobic prokaryotes were engulfed by
eukaryotic cells evolved into mitochondria
(which perform aerobic respiration)
 Photosynthetic prokaryotes were engulfed by
plant cells and evolved into chloroplasts (where
photosynthesis occurs)
How did
we go
from
bacteria to
mammals?
Evolution
What is Evolution?
 Evolution of Dance
Evolution
 The process of change in all forms of life
over generations
 In general: how new species develop
from preexisting species
What does it
explain?
 Does not attempt to
explain the origin of
life
 Does explain how
the most basic early
life forms became
the complex
ecosystem we know
today
Cats
 Define evolution for your bird
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’s Hypothesis
Birds
 What did Lamarck get right?
Cats
 What did Lamarck get wrong?
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 predictions
can
YOU make
observations
can
YOU make
about
the island
about
environment
for
these species of
each
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 whether or not to
publish his results for 25 years.
Darwin’s Theory –
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
Sources of Genetic Variation
That Lead to Evolution
 Sexual Reproduction
 Crossing Over
 Random Independent Assortment of
Chromosomes
 Mutations
Natural Selection
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:
 CCSS ELA 9-10.2
 I can trace the historical development of the
theory of evolution
 I can summarize the evidence for the theory of
evolution
 CCSS ELA 9-10.8
 I can critique and evaluate competing
evolutionary arguments based on scientific
knowledge, empirical evidence and logical
arguments regarding relevant factors.
Objective (Today I will…)
 Explain the idea of “natural selection”
and determine “fittest”
 Examine how adaptations help
animals survive better
Darwin’s reasoning for
Natural Selection
1. Overproduction – more offspring are produced than
can survive due to competition for resources
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 prevalent
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?
Think – Pair – Share
 How can we describe Natural Selection
in just 4 words?
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
What determines fitness?
 The Environment!
 Anything that helps the organism
survive and reproduce better
increases an organisms fitness
Fitness leads to
evolution
Change in Allele
Frequencies
 Natural selection on single-gene traits can lead to a
change in allele frequencies and thus to evolution
 Example: Red lizards are more visible; black lizards
warm faster which allows them to be more active,
sooner.
Fitness leads to evolution
 Peppered Moth evolution
 Peppered moth virtual lab
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.
Birds
 Explain to your cat how the
environment can determine fitness –
use a specific plant or animal as an
example.
(Not one Mrs.
Stewart gave you)
What is a Population?
 A group of organisms of the same
species, that live in the same area,
AND that interbreed
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 (and population’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
Can You…
 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 &
Analogous
Structures
Fossil
Records
Vestigial
Structures
Evidence
of
Evolution
Molecular
Biology
Comparative
Embryology
Evidence of Evolution
 Evidence of evolution on your own
body
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 vs. Analogous
Structures
 Homologous –structures that share the
same basic structure but differ greatly
in function
 Analogous –structures that vary
greatly in structure but share the same
function
Homologous Body Structures
Homologous Body
Structures
 Similar structures with different
functions
 Example: The limbs of reptiles, birds
and mammals (arms, wings, legs and
flippers) vary greatly in function but
are all constructed from the same basic
bones.
Analogous
Structures
Similar
functions but
different
structures
Vestigial Structures
 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
Vestigial Organs
Plica Luminaris = Third Eyelid
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.
 All animals go
through this
process
 Its at the
blastocoel step
that we differ
 Blastopore
could become
mouth or
anus, etc.
Molecular Biology
 Using new technology, we can see how many DNA
and RNA sequences organisms share in common
 Amino acid sequences used to determine how
closely related different species are.
The number of amino acids that differ from
human hemoglobin
Molecular Biology
Amino Acid Similarities
Which two plants are the most closely related
according to this chart?
Assignment:
 Evidence of evolution dry lab activity
packet
Exit Ticket: Socrative.com
Room Number: Stewart 348
Question: How does the environment
determine the “fittest” individual?