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					                   Evolution
Notes Adapted from: www.biologycorner.com
 What is Scientific Theory
 Inscience, theories are
 hypotheses or models that have
 been tested and confirmed many
 times.

       Example of a theory:
       Gravity
    In science, the term
 "Theory" does not express
           doubt.
 They  explain a wide variety of
  data and observations
 They can be used to make
  predictions
 They are not absolute, can be
  changed as new evidence is
  found
 The theory of evolution is considered
 a Unifying Theory of Biology, because
 it answers many questions and offers
 explanations for observations.
    History of Evolution
   Charles Darwin developed the THEORY OF
    EVOLUTION BY NATURAL SELECTION
    – which explained how organisms changed over
      time (ADAPTED)


   Lamarck's Theory of Acquired Characteristics
    – Some thought that you would gain or lose
      features if you overused or didn't use them,
    – PROVEN TO BE WRONG!
                Key Points
1.   Variation exists among individuals in a
     population.
2.   Some variations are favorable.
3.   Not all young in a population can survive
4.   Individuals that survive and reproduce are
     those with favorable variations.
     – This process came to be known as Natural
       Selection
     – The favorable variations are called Adaptations
       Evidence of Evolution
 Fossils
 Evidence from Living Organisms
    – Homologous Structures
    – Analogous Structures
    – Biochemistry and DNA
    – Vestigial Structures
      Observed Changes
 Bacteria  become resistant to
  antibiotics
 Wolves were bred over many
  generations to become dogs (artificial
  selection)
  – then bred further to create a variety of
    breeds
Taxonomy
 The Science of
   Classifying
   Organisms
Why do we need to classify?
 Imagine   a store…..
  – how do you know where to find the milk
    or the cereal? Are they in the same
    aisle?
  – How is the store “organized”? Are all
    stores similar?
 Imagineyour computer or mp3
 player…..
  – are all of your songs and files in a single
    folder or do you have them grouped in
    some way?
   When you have a lot of information, it is
    best to organize and group items so that
    you can find them easier or easily see
    their relationship to other items

...this is why we CLASSIFY


 Even websites must
organize their products
    Scientists also need a way to
         “NAME” organisms
   The “common names” used by
    people can sometimes be misleading or
    confusing

   In order to communicate effectively,
    biologists need a CONSISTENT naming
    protocol.

*Check out these slides of confusing
 names…..
 Sea  Lion
 Ant-lion
 Lion
Which one of these is NOT
    actually a bear?
     What kind of organism is it?
     (invertebrate, mammal, insect, fish,
                  reptile…)
1.    Sea Monkey
2.    Firefly
3.    Ringworm
4.    Jellyfish
5.    Spider monkey
6.    Crayfish
7.    Sea Horse
             Consider this…
 Are all “Grey Wolves” gray?
 Are all “Black Bears” black?
 Which is more venomous…a water
  moccasin or a cottonmouth?

    – Grey wolves can be white, black and any
      shade of gray.
    – Black bears can also be brown or gray
    – A cottonmouth and a water moccasin are the
      same animal – the names vary by region.
     Naming and Organizing are
      part of the same process
   The system was developed by Carolus
    Linnaeus who used Greek and Latin
    names for organisms

   He also created a system where we place
    all organisms into a few “large” groups -
    KINGDOMS - and then those groups are
    further divided into smaller groups
                   Grouping
   Kingdom
   Phylum
   Class
   Order
   Family
   Genus
   Species

   Each group gets smaller and more specific – just
    think of the way you file things on your
    computer into folders and subfolders
   To help you remember the list…
     KING PHILIP CAME OVER FOR GREAT SOUP




Kingdom, Phylum, Class, Order, Family, Genus, Species
          Humans
Kingdom                    Animalia
Phylum                     Chordata
 Class                    Mammalia
 Order                      Primate
Family                    Homindae
 Genus                       Homo
Species                     sapiens

 The scientific name is always the genus + species
               Humans = Homo sapiens
          Lion        Tiger       Pintail Duck
Kingdom   Animalia    Animalia    Animalia
Phylum    Chordata    Chordata    Chordata
Class     Mammalia    Mammalia    Aves
Order     Carnivora   Carnivora   Anseriformes
Family    Felidae     Felidae     Anatidae
Genus     Panthera    Panthera    Anas
Species   leo         tigris      acuta
         More on Naming…

 The system of naming is called BINOMIAL
  NOMENCLATURE - which means it is a 2-
  name system.
 Scientific names must either be underlined or
  italicized
 The genus is always capitalized, the species
  is lowercase
 Can be abbreviated. Ex. P. leo and P. tigris
         What is a species?
   Defined as organisms that can interbreed
    with one another, and produce fertile
    offspring.
   When two organisms of different species
    interbreed, the offspring is called a
    HYBRID
      Check for Understanding
1. Fill in the blanks: Kingdom, _____________, Class,
  Order, ________________, Genus, _______________

2. Which two groups are used for an organism's scientific
  name?

3. Which of the following pairs is MOST closely related?

     Acer rubrum & Acer saccharum
     Acer rubrum & Chenopodium rubrum

4. The system we use for naming is called ____________
   nomenclature.

5. The science of classification is called ____________
             The Kingdoms
 There are currently 5 Kingdoms – all
  organisms can be placed into one of those
  5.
 Classification into a Kingdom is based on
  certain criteria
    – Number of cells (unicellular or multicellular)
    – How it obtains energy (feeding)
    – Type of cell
        Eukaryote (all have nucleus)
        Prokaryote (do not have a nucleus)
    Protist Kingdom
 Unicellular; microscopic
 Nucleus present
    – Eukaryotic
 Autotrophic or heterotrophic
 Classified by how they move
 Plant like: Phytoplankton
    – Provide 90% of worlds oxygen
   Animal like: Zooplankton
    – Their remains are used in cleansers such
      as toothpaste and comet
 Bacteria Kingdom
 Unicellular, microscopic
 Motile (Move)
 No nucleus
    – Prokaryotic
   No chlorophyll
    – Decomposers (Saprophytic)
    – Parasitic
        E. Coli: food poisoning (deadly)
          – Normally found in intestines
    – Beneficial
        Lactobacillus: yogurt and cheese
Fungus Kingdom
 Eukaryotic
 Non-motile (don’t move)
 No root, stem and leaf
 No chlorophyll
    – Decomposers
    – Saprophytic or parasitic
 Reproduce by forming
  spores
 Most are Multicellular:
  mushrooms, bread mold
  etc..
 Unicellular: yeasts
     Plant Kingdom
 Eukaryotic
 Non-motile (don’t move)
 Most plants contains pigments
  (chlorophyll) for photosynthesis
    – Autotrophic
   Can be divided into two groups:
    – Non-flowering plants
    – Flowering plants
Animal Kingdom
Which of these is an
    “animal”?
Answer: They are all animals!


Characteristics of Animals:
  1. Heterotrophic
  2. Eukaryotic
  3. Multicellular
  4. Lack cell walls.
 Dividedinto two groups
 according to the presence
 or absence of backbone:
  – Invertebrates : No Backbone
     Sponges, Cnidarians,
      Flatworms, Round worms,
      Mollusks, Segmented Worms,
      Arthropods, Echinoderms,
      – 95% are Invertebrates
  – Vertebrates : Backbone
     Fish, Amphibians, Reptiles,
      Birds, Mammals
      – 5% = Vertebrates
  Functions of Animals
1. Feeding
   a. Herbivore = eats plants
   b. Carnivore = eats animals
   c. Omnivore = eats plants and animals
   d. Decomposer = feed on decaying
      organic material
   e. Filter Feeders = aquatic animals that
      strain food from water
   f. Parasite = lives in or on another
      organism (symbiotic relationship)
           2. Respiration
•Take in O2 and
give off CO2

•Lungs, gills,
through skin, &
simple diffusion
           3. Circulation
•Very small animals rely on diffusion
•Larger animals have a circulatory system
4. Excretion
Primary waste product is ammonia


5. Response
Receptor cells = sound, light, external
stimuli
Nerve cells => nervous system

6. Movement
* Most animals move
7. Reproduction
Most reproduce sexually
= genetic diversity

Many invertebrates can
also reproduce
asexually to increase
their numbers rapidly
      Body Symmetry
The body plan of an animal, how its parts are
arranged

• Asymmetry - no pattern
  • (corals, sponges)

• Radial Symmetry - shaped like a wheel
  • (starfish, hydra, jellyfish)

• Bilateral Symmetry - has a right and left
  side
   • (humans, insects, cats, etc)
Identify the Symmetry
         Body Sides
anterior - toward the head
posterior - toward the tail
dorsal - back side
ventral - belly side
Cephalization
An anterior concentration of sense organs
(to have a head)
*The more complex the animals becomes
the more pronounced their cephalization.


                             Octopus –
                             member of the
                             class
                             Cephalopoda
                             (head-foot)
 Segmentation
“Advanced" animals have body
segments, and specialization of
tissue (even humans are
segmented, look at the ribs and
spine)
           Body Types…
• Depends on the presence or absence of a
  coelom (body cavity).
• Body types are relative to how animals are
  classified…
Acoelomate: lacks a body cavity.
Pseudocoelomate: posses a fluid filled
cavity between the endoderm and mesoderm.
           (Roundworms and Hydra)

•Differs from a true coelomate because organs
are not entirely lined with mesoderm tissue.
Coelomate: a true body cavity
 forming within the mesoderm.
  (Segmented worms, Muscles, Arthropods, and Chordates.)

• Coelomates fall into either the protostomes or
  deuterostomes category depending on how their
  embryos develop.
           Embryo Development
• Animals begin life as a zygote
   •Fertilized egg




•The zygote divides to form the blastula
  • a hollow ball of cells
• The  Blastula then goes through process
of gastrulation
   • creating the blastopore
     • first opening in the blastula
  •re-arrangement of the cells into three germ
  layers
     • becoming specific structures in the animal.
    Germ Layers
 Endoderm:
     Innermost layer: becomes the lining inside the
      body cavity
        – the digestive and respiratory tract

 Mesoderm:
     Middle layer: becomes the organs inside the body
        – muscle, circulatory, reproductive, and excretory
         systems

 Ectoderm:
      Outermost layer: becomes the body covering.
        – outer layer of skin, sense organs, and nerves
    Protostome and Deuterostome
 Protostomes: "first mouth"
   blastopore develops into a
  mouth.
 Deuterostomes: "second
mouth"
   blastopore develops into an
  anus
   mouth forms second
     hence the naming of
     "second mouth".
  Vertebrates are
  deuterostomes.
              Body Plans
 Mostanimals have a "tube-within-a-tube“
 body plan.
  – This calls for two openings:
     one for food to enter the body (mouth)
     one for wastes to leave the body (anus)
 This plan allows for specialization of parts, such
as a stomach, intestine, etc.

 Animals with the "tube-within-a-tube" plan are
10% more efficient at digesting and absorbing their
food than animals with the sac-like body plan.
 Some   animals have a “sac-like” body
 plan.
 – has only one opening for both food
   intake and waste removal.
 – No tissue specialization or development
   of organs.
 Animal Kingdom Phyla
Phylum Porifera
– Sponges


Phylum Cnidaria
– Sea anemones,
jellyfish, hydra
  -Jelly like animals that
have a bell or umbrella
shape
Phylum Platyhelminthes
-Flatworms
- Soft, thin, and flat bodies




 Free-living Planarian     Parasitic Tapeworm
Phylum Nematoda
– Roundworms



Phylum Annelida
– Segmented worms
              Phylum Mollusca
Clams, squid, snails
 -Soft bodied, usually with a shell
        Phylum Arthropoda
  – Crustaceans, insects, spiders




  This is the largest phylum in the animal
kingdom and contains the most number of
                   species
     They have 3 body parts, jointed legs,
          and a tough exoskeleton.
 Phylum Echinodermata
Starfish
 -Marine animals have plates with spines
Phylum Chordata
Includes all vertebrates
-Notocord (backbone)
Taxonomy

Clades and Keys
      Evolutionary Classification
Phylogeny = the study of evolutionary
  relationships
 Biologists now group organisms into
  categories that represent evolutionary
  descent, not just physical similarities.

   How would you classify a hyena?
   Would you group it with cats or dogs?
    Derived Characters
   Characteristics that appear more
    recently in a group but are not seen in
    older organisms

   Derived characteristics are used to
    construct a CLADOGRAM
    – a diagram that shows evolutionary
       relationships
              Cladograms
   A diagram that shows evolutionary
    relationships
         HOW TO BUILD A
           CLADOGRAM
Watch this animation on how to build a
 cladogram

   http://ccl.northwestern.edu/simevolution/
    obonu/cladograms/Open-This-File.swf
     Identifying Unknown
          Organisms
 When biologists do field
  studies, they often
  encounter new specimens
  that they would need to
  identify
 Field Guides often contain
  pictures for referencing
  organisms
   Dichotomous Keys
A step-by-step guide
to help identify an
organism.
– Which follows a series
  of choices that lead
  you to the organism’s
  name.
        Check for Understanding
1.   A diagram that shows an evolutionary
     relationship is a _______________.

2.   A characteristic that appears only in recent
     members is called a __________ character.

3.   The study of evolutionary relationships is
     called _________.

4.   A system to find the name of an unknown
     organism is a _________ key.

				
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