Transcript Chapter 16 Evolution and Adapations

Evolution
Biological Evolution
Modern humans (Homo sapiens) appear
about 2 seconds before midnight
Age of
reptiles
Insects and
amphibians
invade the land
Plants
invade
the land
Age of
mammals
Recorded human history begins 1/4
second before midnight
Origin of life (3.6–3.8 billion years ago)
Fossils
become
abundant
Fossils
present
but rare
Evolution and
expansion of life
Evolution
The gradual change
in the genetic makeup
of a population or
species overtime
Fossil Record
• Most of what we know of the history of life on
earth comes from fossils (Stephen Gould).
• Gives us physical evidence of organisms.
– Show us internal structure.
• Uneven and incomplete record of species
– We have fossils for 1% of species believed
to have lived on earth.
– Some organisms left no fossils, others
decomposed, others have yet to be found.
• Other info from ancient rocks, ice core, DNA.
4 major mechanisms that
drive evolution:
• Natural Selection- “Survival of the fittest”
• Mutations- Change in the gene structure
due to an outside influence
• Gene Flow- migration into or out of a
population of new genetic variations to an
existing population
• Genetic Drift- changes in the genes over
time
Unifying Principles of Evolution
• Perpetual Change: All species are in a
continuous state of change or Evolution.
Unifying Principles of Evolution
Nature- The combined influences of physical
and biological limiting factors acting upon
an organism.
Natural Selection
The process by which populations
change in response to their
environment as individuals better
adapted to the environment leave
more offspring. Individual that
possess superior physical, behavioral,
or intellectual attributes are more
likely to survive versus those who have
less of these characteristics.
Natural Selection
Natural selection is driving
process of evolution
through the accumulation
of inherited changes over
time.
Adaptation
• An organisms ability to respond to change
• May be structural (how they are built),
behavioral (how they act), or physiology
(how they function in life). Example:
Fish eyes are larger deeper in ocean or even
bioluminescent for those at the bottom
Bird beak size to change feeding habits
based on food types, Migration of birds
south, Homologous structures, camouflage.
The Case of the
Peppered Moths Adaptation
• Industrial revolution
–Pollution darkened tree trunks
• Camouflage of moths increases survival
from predators
• Natural selection caused a shift away
from light-gray towards dark-gray moths
Fig. 18.5, p. 287
Fox Adaptations
Make a list of the adaptations a
fox would have to make to have
the best chances of survival if
one fox species lives in the
Arctic and the other species
lives in the Tropics.
Arctic Fox
Tropics Fox
Fox Structural Adaptation
Northern
population
Early fox
population
Spreads
northward
and
southward
and
separates
Arctic Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Southern
population
Gray Fox
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
Avian Dinosaurs: Birds
Based on taxonomy classification, all birds
evolved from dinosaur ancestors.
Archaeopteryx is believed to be the link of birds
with dinosaurs. Dinosaurs are REPTILES.
Figure 06A & B: Archaeopteryx
Reproduced from Heilmann, G. The Origin of Birds. Appleton, 1927 (Reprinted Dover Publication, 1972)
How did birds have to
adapt to move away from
the dinosaur classification
to the classification of
BIRDS?
What had to evolve for birds to fly?
1. Feathers had to evolve from scales.
2. Bones became hollow to reduce
weight
3. Strong breast muscles for flight
4. Four chambered heart for
increased oxygen to muscles
The Origin of Feathers
• Feathers evolved from reptilian scales
for insulation and display
– Three major hypotheses for their origin:
• Feathers were an adaptation for insulating the
(presumed) warm-blooded and grounddwelling reptilian ancestors of birds
• Ancestral birds were tree-dwelling reptiles
that used their developing wings to glide from
branch to branch
• Ancestral birds were ground-dwelling runners
whose feathers formed planing surfaces
increasing their speed
Invading the Air: Flying Reptiles
• Known adaptations for sustained powered
flight have appeared only three times in the
evolution of terrestrial vertebrates: in
pterosaurs, birds and bats.
– Pterosaurs and Pterodactyls
Figure 05: Pteranodon
© Paul B. Moore/ShutterStock, Inc.
Figure 04A: Pterodactyloids
Genetic Variation
• Provide material for natural selection
• Brought about by mutation
• Provides genetic diversity
–Allows a species to adapt a new
niche in its environment
• Leads to Natural Selection
• Leads to New Species (speciation)
Jean Baptiste Lamarck
Lamarck believed that if the giraffes’ neck
became longer from stretching it could be
inherited by their offspring or by not using a
trait it could disappear from their offspring.
He believed in “acquired characteristics”. This
theory is totally untrue. Example baseball
player passing his acquired abilities to his son,
a boxer passing his acquired skills to his son,
or a PHD passing their knowledge to their
children.
Galapagos Finches
• Some 10000 years ago a number of small
finches most likely grass quilts made their way
from South America 600 miles across the
Pacific Ocean to the Galapagos Islands.
• Because of the great distance from South
America the island was isolated and new
species arrive relatively infrequently and
when the grass quilts arrived they found a
land that was free of completion for them.
They developed into many species taking on
adaptive beaks to improve their food
chances.
Galapagos Finches
Review
• Evolution is driven by Natural Selection
or Survival of the Fittest.
• Structural Adaptation- long neck, short
ears. Behavioral Adaptation- birds and
caribou migrating, and animals
hibernating.
• All living organisms are traced back to a
Common Ancestor
• Of all the species that have ever lived
most are now extinct (99.9%).
Review
Of all the species that have ever lived most are
now extinct (99.9%).
Adaptation enhance an organism’s ability to
survive and reproduce.
With changing tectonic plate locations:
1. Life forms have become extinct
2. New lifeforms have evolved
3. Lifeforms have changed or evolved over
time;
Speciation
Horse Evolution
Mnemonic Device
Create a Mnemonic device to
remember the evolutionary
order of Bacteria,
Invertebrates, Fish,
Amphibians, Reptiles,
Insects, and Mammals
Bacteria I FARM
Extinction
True extinction is the
elimination of every
member of a species.
Examples Carrier pigeon,
dinosaurs, whooping crane
Extinction
• Local, mass, and true extinction
• The ultimate fate of all species
just as death is for all individual
organisms
• 99.9% of all the species that
have ever existed are now
extinct
Extinction
Extinctions open up new opportunities
for speciation and adaptive
changes. Generally after a mass
extinction the species that survive have
fewer predators and possibly more
food sources thus more chance for
their populations to grow quickly and
adding diversity to their species.
Local extinction- species has disappeared from a
local area due to loss of habitat, food, or out
numbered by predators.
Mass extinction– 25-90% of total species
– Five great mass extinctions in which numerous
new species evolved to fill new or vacated
niches in changed environments (at end of
Precambrian, Ordovician, Devonian,
Permian[worst of all], and Cretaceous).
– 10 million years or more for adaptive changes
to rebuild biological diversity following a mass
extinction
Extinctions
• Habitat Disruption
– Volcanic Eruptions
– Asteroid Impacts
– Sea Level Change
• Habitat Modification
–
–
–
–
–
Climate Change
Mountain-Building
Sea Level Change
Precipitation Change
Toxic Materials
• “Exotic” Species Introductions
– Continental Drift
Extinction in the Context
of Evolution IF
1. The environment changes rapidly and
2. The species living in these environments do not already
possess genes which enable survival in the face of such
change and
3. Random mutations do not accumulate quickly enough
then or
4. New predators introduced or major food source lost then
All members of the unlucky
species may die
Extinction
The greater the diversity of
genotypes and phenotypes
among a population the less
likely an extinction will
occur.
Comparative Anatomy
Comparative Anatomy includes
Homologous, Analogous and Vestigial
structures.
Comparisons of anatomical features in
different organisms often provides
evidence to support the theory of
evolution. As Organisms are often classed
together according to similarities in their
structures.
Homologous Structures
• Homologous structure are structures
that share a common origin but may
serve different functions in modern
species.
• These structures are evidence that
organisms with similar structure
evolved from a common ancestor.
• Examples include the forelimbs of a
variety of mammals. For example,
human, cat, whale and bat.
Homologous Structures
• These species show the basic same skeletal
elements .
• However these skeletal elements have been
modified over time to suit the different
functions suitable for the type of mammal.
• Homologous structures result from divergent
evolution meaning their ancestral lines
started out fairly similar, but evolved along
different paths, becoming more different
over time.
• Structures that are similar due to evolutionary origin, such as
the forearm bones of humans, birds, porpoises, and elephants,
are called homologous. However, structures that evolve
separately to perform a similar function are called analogous.
The wings of birds, bats, and insects, for example, have
different embryological origins but are all designed for flight.
Homologous Structures
Birds and Reptiles
• Both have scales
• Reptile fossils most
common to modern
birds
4/11/2017
Homologous structures in
Cow and Human eyes
Humans and cows share
homologous structures in the
eyes of the iris, cornea, lens, and
optic nerve. They are similar
structures in two different
animals that serve the same
purpose.
Analogous Structures
However, structures that evolve
separately to perform a similar
function are called analogous. The
wings of birds, bats, and insects, for
example, have different
embryological origins but are all
designed for flight.
Analogous Structures
• Analogous structures are a
contrast to homologous
structures.
• They serve the same function
between organisms but are
different in internal anatomy.
www.encarta.co
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 Such as the wings of birds and
butterflies or the eyes of lobsters
and fish.
• These structures are of no use
in classifying organisms or in
working out their evolutionary
relationships with each other.
Figure
4
Vestigial Structures
Bones or other structures that are
present in an organism but are
reduced in size, have no use or a
less prominent function than in
other organisms. Examples: the
human tail bone(coccyx), wings of
the flightless cormorant, wings of
an ostrich.
Flightless Cormorant
Embryonic Development
Genotype/Phenotype
Genotype- how an organism is
made up of the genes from its
parents: genetic makeup cannot
be seen (ATCGTACGTTACG).
Phenotype- how an organism
looks: the observable traits of an
organism; picture
What kind of structures are these
What kind of structures are these
Aristotle
Aristotle (384-322 B.C.) was a philosopher and
a naturalist who first tried to group plants and
animals into groups based on categories. The
Greeks and Romans tried to also classify
organisms into basic categories. Carl Linnaeus
was the first to really publish a system of
classification. He is famous for the use of
Binomial Nomenclature.
Carl Linnaeus
Was a Swedish biologist who became
interested in how to classify
organisms. The science of
classification is called Taxonomy.
Carl Linnaeus(1707-1778) introduced
the system of binomial nomenclature
that used genus and species to
identify a organism.
Taxonomy Uses
1) helps scientists organize info
for identification around the
world
2) easy to ID creatures
3) makes it easy to ID new
species
Taxonomy Major Classifications
Broad
Narrow
Kingdom
Phyla
Class
Order
Family
Genus
Species
Create a Mnemonic Device
1-You will have to Know how to place
the categories of Taxonomy in Order for
the Unit Test
2-Kitchen Patrol Cooks Orders For
General Staff
3-Keep Plates Clean Or Families Get Sick
4-Kids Playing Chess Occasionally Fa_ _
Green Slime
Genus is always capitalized and
species is always lower case.
Both are italicized.
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Apis mellifera- European honeybee
Canis familiaris- Common dog
Homo sapiens- Modern man
Felinus catus- Cat
• Using Genus and Species name is
called Binomial Nomenclature
Species
• A species is a group of organisms
that can interbreed and produce
fertile offspring. The key is fertile
offspring to carry on the species.
• Horse and donkey can mate but
produce a sterile organism called
a mule.
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Human Taxonomy
Kingdom- Animalia
Phylum- Chordata
Class- Mammalia
Order- Primata
Family- Hominidae
Genus- Homo
Species- Homo sapiens
Homo sapiens
means
“wise man”
Killer Whale Taxonomy
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Kingdom-Animalia
Phyla- Chordate
Class-Mammalia
Order-Cetacea
Family-Delphinidea
Genus-Orcinus
Species-Orcinus orca
Honeybee Taxonomy
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Kingdom- Animalia
Phylum- Anthropoda
Class- Insect
Order- Hymenoptera
Family- Apidea
Genus- Apis
Species- Apis mellifera
Human DNA is similar to a
chimpanzee(98.4%) and to
a banana (60%). DNA is
becoming the tool for
modern scientist to classify
organisms with.
Geologic Order of Organisms
1- Bacteria- first life on Earth
2- Invertebrates-no backbone
3-Fish-the first vertebrates
4-Amphibians-land and water animal
5-Reptiles-the first true land animal
6-Mammals
Mnemonic device= Bacteria I FARM
Man’s Greatest
Changes
Bipedal-walk upright
Opposable thumbs- able to
grasp and pick up objects
Binocular vision-two eyes that
focus together for depth vision.
Theories on How Life
Originated
1.Spontaneous Origin2.Divine Creation3.Extraterrestrial Origin4.Evolution-
Spontaneous Origin
All things are made up of the same
basic elements. Carbon, Nitrogen,
Oxygen, and Hydrogen. Through
chemical and physical processes life
formed in very simple life forms and
grew to more complex forms through
the billions of years of Earth’s history.
Poof; Life just appeared by mixing the
elements. Stanley Miller experiments.
Divine Creation
A divine creator made life out
of the elements that were
present when Earth formed.
Divine creation believes that
man was created versus
evolving.
Extraterrestrial Origin
This theory suggests that life was
carried to Earth by a meteorite or
asteroid and life did not form on
Earth at all. A book from the 1970’s
called “Chariots of the Gods”
discusses Earth being visited by
Aliens.
Evolution
Life formed and evolved
through natural selection,
adaptations, and mutations
to DNA that lead to more
and more complex life.
Tectonic Plate Movement
The greatest event causing
diversity in species is the
movement of the tectonic
plates causing the species to be
isolated from each other and
thus creating more opportunity
for diversity within the species.
Tectonic Plate Movement
Caused Climate change
Isolation of species
More opportunity for diversity
of species
Genotype
Genotype is the make up of the
genes in an organism that
determines it characteristics.
Genotype can be changed by
mutations that accumulate over
time.
Phenotype
Phenotype is what we see
as the characteristics of an
organism.