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EVOLUTION: the process of change in allelle frequency over time


EVOLUTION: the process of change in allelle frequency over time Evolution is the idea that new species develop from earlier species by accumulated changes. – PowerPoint PPT presentation

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Title: EVOLUTION: the process of change in allelle frequency over time

EVOLUTION the process of change in allelle
frequency over time
  • Evolution is the idea that new species develop
    from earlier species by accumulated changes. This
    is also referred to as descent with

Jean Baptiste Lamarck Use and Disuse Hypothesis
Inheritance of Acquired Traits
No longer accepted- Behavior does NOT affect
Lamarcks Theories
  • Tendency Toward Perfection acquiring features
    that help them live more successfully in their
  • Ex birds and flying
  • Use and Disuse Alter size and shape of their
  • Ex birds transform front limbs to wings
  • Inheritance of Acquired Traits pass on traits
    to offspring
  • Ex weight lifter

Charles Darwin 1831 Traveled to the Galapagos
Islands where there was a variety of climates
among the islands
He observed much diversity in living things and
how well suited they were to their environments.
Darwin observed variety within species and also
studied artificial selection
Led him to the theory of evolution by natural
What is natural selection? Struggle for
existence leads to survival of the fittest
(Natural Selection)
The fittest are those with an inherited
characteristic that makes it better suited to
survive and reproduce. These characteristics
are called Adaptations.
Adaptations!Inherited characteristic that
increase an organisms chance of survival
  • Why are most animals in the artic white?
  • So they blend in with the snow and avoid being
  • Why do sharks have such sharp
  • teeth?
  • It allows them to catch their prey!
  • Why do elephants have such big ears?
  • To let heat escape their bodies so they can
  • stay cool!

Natural Selection results in changes in
inherited characteristics of a population due to
the environment, increasing the species fitness
in that environment. These changes are observed
over long periods of time and many generations.
Hutton and Lyell
  • Studied geology and geological change
  • Discovered that the Earth is millions of years
  • The process that changed Earth in the past are
    the same processes that operate in the present
  • Weathering of rock
  • Uplifting to form mountain ranges

Lyells Influence on Darwin
  • If the Earth can change over time, might life
    change as well?
  • Realized it would take many, many years for life
    to change in the way he suggested
  • This would only be possible if the Earth were
    extremely old!

Population Growth
  • Malthus reasoned that if the human population
    continued to grow unchecked, sooner or later
    there would be insufficient living space and food
    for everyone.
  • Darwin asked a couple of questions
  • What causes death of so many individuals?
  • What factors determine which ones survive and
    reproduce and which ones do not?

5 parts of Darwins Theory of Natural Selection
  • Genetic Variation Ultimate source MUTATIONS!
  • Overproduction of Offspring
  • Struggle for Existence
  • Survival of the Fittest
  • Descent with Modification

Organisms produce more offspring than can survive.
  • Example A frog can lay 200 eggs, yet not all
    eggs will survive to become
    adult frogs.

Struggle for Existence
  • Members of each species compete regularly to
    obtain food, living space, ect.
  • Prey faster, better camouflaged, or better

Survival of the Fittest
  • How well an organism is suited to its environment
  • Fitness ability to change (adapt) in order to
    be able to survive and reproduce
  • Is this always the strongest or the biggest

Descent with Modification Common ancestor and
change over time in a population
All living things are related due to common
ancestors- Principle of Common Descent
Results of Evolution -- Speciation!!
  • Speciation is the process that creates new
  • A species is a group of organisms that can
    naturally interbreed and produce fertile
  • The Liger--the offspring of a tiger and a lion.
  • Tigers and lions are still considered separate
    species, because although they can produce
  • offspring, the offspring
  • is not fertile.

Evidence of Evolution
A. Fossils Mineralized remains or imprints of
organisms from the past Missing Links
Intermediate fossils between groups of
organisms Fossil record is not complete!
B. Geographic distribution of living species
Species evolve differently in different
environments Different species evolve
similarly in the same type of environment
C. Amino Acid Sequences (DNA Evidence) More
closely related, more aa sequence similarities
should be seen
D. Anatomy Similar body structures that dont
necessarily have similar functions (Homologous
Structures) Similar structures with reduced
size and lesser function or no function
(Vestigial Structures)
Evidence of Evolution --Anatomical/Physiological
  • Notice how there are similar bones and similar
    structures in humans, birds and whales!
  • Can you tell which is the bird and
    which is the whale?

Analogous Structures
  • Serve the same function but are anatomically
    different. Serve as evidence that the organisms
    evolved independently

Vestigial Organsorgan that serves no useful
functionover generations, they reduce in size
Evidence of Evolution -- Embryology!
  • It is believed that all vertebrates evolved from
    a common ancestor. The genetic
    information that guides their
    development is nearly the same.
  • That's why scientists can learn about human
    development by studying other organisms--including

E. Embryonic Development Similarities in
development of embryos of organisms
  • Extinction occurs when there
    are no members of a species
    left alive.

5 parts of Darwins Theory of Natural Selection
  • Genetic Variation Ultimate source MUTATIONS!
  • Overproduction of Offspring
  • Struggle for Existence
  • Survival of the Fittest
  • Descent with Modification

Relative vs. Absolute Dating
Comparing Relative and Absolute Dating of Fossils
Relative Dating
Absolute Dating
Can determine Is performed by Drawbacks
Principle of Superposition
  • In an undisturbed sequence of sedimentary rocks,
    the oldest rocks are on the bottom with the most
    recent on top.

How fossils are formed
Water carries small rock particles to lakes and
Dead organisms are buried by layers of sediment,
which forms new rock.
The preserved remains may later be discovered and
Summary of major events (pg. 429-34)
(millions of years ago)
Key Events
Glaciations mammals increased humans Mammals
diversified grasses Aquatic reptiles
diversified flowering plants mass
extinction Dinosaurs diversified
birds Dinosaurs small mammals cone-bearing
plants Reptiles diversified seed plants mass
extinction Reptiles winged insects diversified
coal swamps Fishes diversified land vertebrates
(primitive amphibians) Land plants land animals
(arthropods) Aquatic arthropods mollusks
vertebrates (jawless fishes) Marine invertebrates
diversified most animal phyla evolved Anaerobic,
then photosynthetic prokaryotes eukaryotes, then
multicellular life
Cenozoic Mesozoic Paleozoic Precambrian Ti
Quaternary Tertiary Cretaceous Jurassic Triassic P
ermian Carboniferous Devonian Silurian Ordovician
1.8present 651.8 14565 208145 245208 290245
363290 410363 440410 505440 544505 650544
Hypothesis of early Earth
  • Very hot surface from colliding meteorites
  • Very hot planet core from radioactive materials
  • Volcanoes spewing lava and gases that helped to
    form the early atmosphere

Hypothesis of early Earth
  • About 4.4 billion years ago, Earth might have
    cooled enough for the water in its atmosphere to
  • This might have led to millions of years of
    rainstorms with lightning, enough rain to fill
    depressions that became Earths oceans.
  • The oldest rocks dated are 3.9 million years old.

Fossils evidence of an organism that lived long
ago that is preserved in Earths rocks
  • Paleontologists estimate that about 95 species
    are extinct from lifes origins.
  • Climate and ancient geography can be determined
    from fossils.

Types of Fossils
Fossils Types
A trace fossil is any indirect evidence
A trace fossil is any indirect evidence
Trace fossils
left by an animal and may include a
footprint, a trail, or a burrow.
When minerals in rocks fill a space
left by a decayed organism, they make
a replica, or cast, of the organism.
A mold forms when an organism is
A mold forms when an organism is
buried in sediment and then decays,
leaving an empty space.
Petrified-minerals sometimes penetrate
and replace the hard parts of an
organism. Permineralized-void spaces
in original organism infilled by
At times, an entire organism was
Preserved or
quickly trapped in ice or tree sap that
frozen fossils
hardened into amber.
What has been learned from fossils
  • several episodes of mass extinction that fall
    between time divisions
  • mass extinction an event that occurs when many
    organisms disappear from the fossil record almost
    at once
  • The geologic time scale begins with the formation
    of Earth about 4.6 billion years ago.

Continental drift
  • Earths continents have moved during Earths
    history and are still moving today at a rate of
    about six centimeters per year.
  • The theory for how the continents move is called
    plate tectonics.

Miller-Urey experiment showed one possible way
for inorganic molecules to form organic molecules.
Mixture of gases simulating atmospheres of early
Spark simulating lightning storms
Cold water cools chamber, causing droplets to form
Condensation chamber
Water vapor
Liquid containing amino acids and other organic
Endosymbiotic theory
  • Eukaryotic cells may have engulfed prokaryotic
    cells by mutualism created the first
    mitochondria. Autotrophic bacteria are
    Cyanobacteria with chlorophyll
  • So, Eukaryotic cells may have engulfed
    prokaryotic cyanobacteria by mutualism created
    the first chloroplast.

  • Large-scale evolutionary patterns and processes
    that occur over long periods of time.
  • Includes 6 topics
  • Extinction
  • Adaptive radiation
  • Convergent evolution
  • Divergent evolution
  • Punctuated equilibrium
  • Changes in developmental genes

Patterns of evolution
  • Darwin believed that organisms evolved gradually.
  • Niles Eldredge and Stephen Jay Gould believed
    punctuated equilibrium is how organisms evolved,
    periods of rapid evolution followed by periods of

Adaptive Radiation
  • Single species or small groups of species evolved
    into diverse forms living in different ways.

Convergent Evolution
  • Adaptive radiation can produce unrelated
    organisms that look similar due to similar

  • Example This butterfly acquires a cardiac
    glycoside from members of the genus Asclepias.
    Because of their milky sap, these are commonly
    referred to as milkweed plants. The plants
    produce this toxin as a defense against
    herbivory, but the Monarch has the ability to
    sequester the toxin in fatty tissues so that it
    makes the butterfly unpalatable while not
    poisoning the butterfly.

The process by which two species evolve in
response to changes in each, other over time.
http//ecology.botany.ufl.edu/ ecologyf02
Levels of Organization 1. species-a group of
organisms so similar to each other that
they can breed and produce fertile offspring
2. populations-groups of individuals of the same
species that live in in a given area 3.
communities-all the different populations that
live in a defined area 4. ecosystem-all
the communities in a given area together
with the physical environment 5. biome-a group
of ecosystems that have the same climate
and similar dominant communities
II. Energy Flow A. Producers or
Autotrophs-use energy from the environment to
assemble simple inorganic compounds into
complex organic molecules make their own
food! 1. photosynthesis-process through which
plants and algae take light energy to power
chemical reactions that convert CO2 and H2O
into O2 and energy-rich carbohydrates 2.
chemosynthesis-process through which some
bacteria break down inorganic molecules
releasing energy that they use to make energy-
rich carbohydrates
Capture energy from sunlight or chemicals and use
that energy to produce food.
Use energy from the environment to fuel the
assembly of inorganic compounds into organic
(Includes plants, some algae, some bacteria)
B. Consumers or Heterotrophs-cannot harness
energy from the environment must get their
energy from other organisms 1. herbivores -
eat only plants 2. carnivores - eat only
animals 3. omnivores - eat both plants and
animals 4. detritivores eat dead matter and
recycle them to the soil 5. decomposers
break down organic matter
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D. Ecological Pyramids- a diagram that shows the
relative amounts of energy or matter
contained within each trophic level in a
food chain or web 1. Energy pyramid- Only
about 10 of the energy available within one
trophic level is transferred to organisms at
the next trophic level Rest is given off
as heat!!! 2. Biomass pyramid biomass-the
total amount of living tissue within a given
trophic level 3. Pyramid of numbers- shows
relative number of individual organisms at each
tropic level
Only about 10 of available energy transfers to
the next level
If we start with 4000 calories of food energy
at the base, how much is available for the
man? How much would he lose as heat and use
for body processes?
Pyramid of Numbers
When would a pyramid of numbers not appear as a
Cycles of Matter
  • Unlike energy flowing in one direction, matter
  • Biogeochemical cycles
  • Systems do not use up matter, they transform it
  • The same molecules are passed around again and
    again in the biosphere.
  • Nutrients all chemical substances that an
    organism needs to sustain life.
  • Passed between organisms and environment

The Water Cycle
Carbon Cycle
  • Four main process move carbon through its cycle
  • 1. Biological process- photosynthesis,
    respiration and decomposition
  • 2. Geochemical process- erosion and volcanic
  • 3. Mixed biogeochemical- burial and
    decomposition of dead organisms converted into
    fossil fuels
  • 4. Human activities- mining, cutting and burning
    forests and burning fossil fuels

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Nitrogen Cycle
  • Organisms require nitrogen for AA.
  • Most abundant nitrogen gas or N2 - 78 of
  • Ammonia, nitrate and nitrite ions are found in
    waste products
  • Also found in ocean and large water bodies
  • Human activity adds nitrogen as nitrate due to
  • Nitrogen fixation bacteria covert nitrogen gas
    into ammonia ? Nitrates/nitrites ? producers use
    these to make proteins!!
  • Denitrification When organisms die, decomposers
    return nitrogen to the soil as ammonia taken in
    by producers. Soil bacteria convert nitrates ?
    nitrogen gas, releasing nitrogen back into the

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Phosphorus Cycle
  • Essential because part of DNA and RNA
  • Not very common in the atmosphere
  • Remains mostly on land in rock and soil minerals,
    and in ocean sediments as inorganic phosphate.
  • When rocks and sediments wear down, phosphate is
  • On land, some of the phosphate washes into rivers
    and streams where it dissolves.

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Nutrient Limitation
  • Primary Productivity rate at which organic
    matter is created by producers
  • Factors amount of nutrients available
  • Limiting Nutrient single nutrient that limits
    ecosystem because is scarce or slowly cycles
  • Nitrogen in oceanic environments
  • Phosphorus in freshwater environments
  • Ex. Farmers use fertilizers
  • Algal bloom

Types of Symbiosis
  • Mutualism
  • both species benefit
  • Commensalism
  •   one species benefits, the other is unaffected
  • Parasitism
  •   one species benefits, the other is harmed
    (must have a host)
  • Predation
  • One species benefits, the other is harmed.

  • Occurs when organisms of the same or different
    species attempt to use an ecological resource in
    the same place at the same time.
  • Resources-any necessity of life

Competitive Exclusion Principle
  • No two species can occupy the same niche in the
    same habitat at the same time.

A. biotic factors- the biological
influences on organisms within an
ecosystem -living things! B. abiotic
factors-physical or nonliving factors that
shape an ecosystem -nonliving things! C.
niche-the full range of physical and biological
conditions in which and organism lives and how
it uses them
NICHE describes the job of the organism within
the ecosystem it is the full range of physical
and biological conditions it lives in and out it
uses those conditions!
Here is a picture of a worm and its nichehow can
we describe a worms niche? Describe your
The Role of Climate
  • Are all species able to tolerant all
    environmental conditions?
  • Temperature, precipitation and other
    environmental factors in the atmosphere combine
    to produce climate and weather.
  • Weather-day to day
  • Climate-year to year
  • Climate is caused by many factors.

The Greenhouse Effect
  • Atmospheric gases trap heat energy and maintain
    Earths temperature range.
  • Gases act like a glass window of a greenhouse.
  • Heat is retained by layer of greenhouse gases
    creating effect.

Greenhouse Effect
  • Greenhouse gases allow solar energy to penetrate
    the atmosphere.
  • Converted into heat energy as it hits the Earths
    surface and radiates back into the atmosphere.
  • But, the gases do not allow the escape as easily
    as the entrance.
  • In turn, heat is trapped in the atmosphere.

Latitudes Effect on Climate
  • Earth is tilted, so solar radiation strikes at
    different parts of Earths surface at angles that
    vary at different times of year.
  • This causes three climate zones polar, temperate
    and tropical

Winds and Ocean Currents
  • The unequal heating of Earths surface drives
    wind and ocean currents transporting heat
    throughout the biosphere.
  • The upward movement of warm air and downward
    movement of cool air create air currents or winds
    moving heat.
  • The flow of water due to temperature as well as
    by winds causes ocean currents.
  • Ocean currents also transport heat energy and in
    turn affect weather and climate.

Ecological Succession
  • Ecosystems constantly change due to natural and
    human disturbances.
  • Series of unpredictable changes
  • Primary succession succession that occurs on
    surfaces with no soil
  • Ex. After a volcanic eruption
  • Pioneer species
  • Secondary succession soil is present
  • Ex. Land cleared for farming is abandoned or
    after wildfires in woodlands

Aquatic Ecosystems
  • Determined primarily by depth, flow, temperature,
    and chemistry of the overlying water.
  • Marine saltwater/oceanic
  • Limiting Nutrient nitrogen!
  • Freshwater flowing (rivers) or standing (lakes,
  • Limiting Nutrient phosphorus!

  • Complex terrestrial communities that covers a
    large area
  • Tolerance ability to survive and reproduce under
    conditions that differ from optimal ones
  • Microclimate

The History of Organization

Aristotle 384-322 BC Interested in biological
classification. Patterns in nature.
Carl Linnaeus 1707-1778 ACE Father ofBiological
Binomial Nomenclature
  • Two-word naming system
  • Genus
  • Noun, Capitalized, Underlined or Italicized
  • Species
  • Descriptive, Lower Case, Underlined or Italicized
  • Ex Homo sapien

What is Classification?
Scientist who classify or organize organisms
(animals and plants) are called taxonomists.
Taxonomists study taxonomy. Classification
arranges objects, ideas, or information into
groups by finding common traits or
Cladograms are used to
  • Organize organisms based on evolutionary
  • In other words
  • who is related to who and where did we come from
  • Groups are also arranged in
  • hierarchical order.

Hierarchical Classification
  • Taxonomic categories
  • Kingdom (big) King
  • Phylum Philip
  • Class Came
  • Order Over
  • Family For
  • Genus Grape
  • Species (small) Soda

Using a dichotomous key
  • At each step of the process of using the key, the
    user is given two choices each alternative leads
    to another question until the item is identified.
  • 1a. If the leaves are flat.go to question 4.
  • 1b. If the leaves are needle-like.go to
    question 2.
  • 2a. Are the needles in a bunch? Go to question
  • 2b. Are they spread along the branch?pine tree
  • Eventually, when enough questions have
    been answered, the identity of the tree is

  • Gene mutations result from changes in a single
    gene. Chromosomal mutations involve changes
    whole chromosomes.

Gene Mutation
  • Point Mutation Affect one nucleotide thus
    occurring at a single point on the gene. Usually
    one nucleotide is substituted for another
  • Frameshift Mutation Inserting an extra
    nucleotide or deleting a nucleotide causes the
    entire code to shift.

Gene Mutation
Chromosomal Mutations
  • Deletion Part of a chromosome is deleted
  • Duplication part of a chromosome is duplicated
  • Inversion chromosome twists and inverts the
  • Translocation Genetic information is traded
    between nonhomologous chromosomes.

Chromosomal Mutations
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