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Life Structure and Classification

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Life Structure and Classification What are living things like? Any living thing is an organism Organisms : are organized: grow and develop: respond – PowerPoint PPT presentation

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Title: Life Structure and Classification


1
Life Structure and Classification
  • What are living things like?
  • Any living thing is an organism
  • Organisms
  • are organized
  • grow and develop
  • respond
  • maintain homeostasis
  • use energy
  • reproduce

2
Organized
  • All living organisms are composed of cells
  • Cells are smallest unit of life that carries on
    the function of life
  • Cells take in materials and use them in complex
    ways
  • Have orderly structure and instruction for
    transfer of heriditary material

3
Living Things grow and Develope
  • Single cell organisms increase cell size
  • Multi-celled organisms grow by increasing number
    of cells
  • Changes that take place during lifetime is known
    as development
  • Figure 2 shows examples of development
  • Life span is the length of time an organism is
    expected to live

4
Living things Respond
  • Living things interact with their surroundings
  • Anything that causes change in an organism is a
    stimulus and the reaction to that is a response
  • Organisms must respond to stimuli to carry on
    daily activity and to survive

5
Maintain Homeostasis
  • Inside cells they must respond to stimuli within
    (water or food levels within)
  • Cells internally make adjustments
  • This regulation of an organisms internal life
    maintaining conditions that is in response to
    its environment is called homeostasis

6
Living things use energy
  • All energy for cells originates from the sun
  • Plants use sun directly to produce energy
    (photosynthesis) where H2O CO2 produces C6H12O6
    (carbohydrates) and O2
  • Animals and some other organisms take in
    carbohydrates and oxygen to produce its energy
  • Some bacteria deep in dark ocean floors use
    stored energy in chemical compounds to make food

7
Living things must reproduce
  • In order for an organism to continue to its own
    kind it must be able to reproduce itself

8
What do living things need to survive
  • Place to live
  • Needs water
  • Water transport minerals within and between cells
  • Water is released by organisms and homeostasis is
    maintained
  • Needs food source
  • Animals need to take in food, where plants
    produce their own food
  • Organisms die and are decomposed by
  • other organisms that are reused again

9
How are living things classifiedsection 2
  • Carolus Linnaeus
  • Developed a system of organizing organisms by
    similar structure in system called Binomial
    Nomenclature.
  • Used Scientific Names rather than common names
  • Modern classification use structure, hereditary
    information and early stages of development

10
Binomial Nomenclature
  • Two word naming system (latin names)
  • First word is the genus name (contain similar
    species)
  • Second word is the species name
  • Can describe a feature, place or honor an
    individual
  • Ambystoma tigrinum (salamander named because of
    tiger stripes)
  • Organisms of same species can reproduce amongst
    themselves

11
Scientific NamesWhy they are important
  • Help avoid confusion with common names
  • Organisms with similar evolutionary histories are
    group together
  • Gives descriptive information about species
    (tiger salamander)
  • It is organized efficiently

12
Classification Order
  • Organisms are classified in following order
  • Kingdom
  • Phylum (Division in plants)
  • Class
  • Order
  • Family
  • Genus
  • species

13
Modern Classification
  • Today scientist use phylogeny to classify
    organisms
  • Uses fossils, evolutionary history and changes
    over time to classify
  • Smallest group is a species
  • Broadest group is Kingdom
  • Figure 6 in book classifies a brottle nosed
    dolphin

14
Tools for Identifying Organisms
  • Field guides and dichotomous keys aide to
    identify organisms
  • Dichotomous key (use 2 characteristics that you
    choose between that leads to identification of
    organisms)
  • The key will lead to genus-species final name of
    organism

15
Cell Structuresection 3
  • Viewing cell structure
  • First developed by using two magnifying glasses
    together to see larger view of cells
  • Leeuwenhoek (Dutch) saw inside cells (1600s)
    called them beasties

16
Development of Cell Theory
  • Hooke in 1665 sliced a piece of cork and saw
    empty space he called cells
  • 1830 Scheiden used a microscope to study plant
    parts and called them cells
  • Schwann observed animal cells
  • Both men combined their ideas and were convinced
    all living things are made of cells
  • Mid 1800s Virchow proposed that cells divide
    and every cell comes from a cell that already
    existed

17
Cell Theorytable 2 (page 221)
  • All Cells are made up of one or more cells
  • Cells are the basic unit of organization in
    organism
  • All Cells come from pre-existing cells

18
Cell organization
  • Scientists divide cells that have a membrane
    bound structure and those that dont
  • Cells without a membrane are called prokaryote
    cells
  • Cells with a membrane around the cell are called
    eukaryote cells
  • Each cell performs specific functions but all
    cells must take in nutrients, store, produce and
    breakdown substances, take in and use energy
  • Structure of cells perform certain functions

19
Cell Wall
  • Tough rigid outer coverings that protect cells
    and give them shape
  • Found in all plants, algae, fungi and most
    bacteria
  • Plants cell wall contain mostly cellulose
    (carbohydrate) and allows water and nutrients in
    and out
  • Pectin (found in plant cell walls) is glue-like
    structure that has thick structure (jams and
    jellies)
  • Lignin (makes cell walls rigid) found mostly in
    plant cells that aide in supporting plants

20
Cell Membrane
  • All cells contain a cell membrane
  • It is the outermost covering of cells unless they
    have a cell wall
  • Regulates interactions between cells and
    environment
  • Allows nutrients to move in and wastes to leave
    cell

21
Cytoplasm
  • Gell-like substance inside cell membrane is
    called cytoplasm
  • Life processes take place here
  • Prokaryote cells cytoplasm contains the
    hereditary material
  • All organelles are located here
  • Cytoskeleton found in cytoplasm is made of
    proteins that help cell change shape, enable some
    cells to move

22
Manufacture of Proteins in Cells
  • Every cell activity involves proteins
  • Proteins are part of cell membrane and are part
    of all chemical reactions in cell
  • Ribosomes produce protein in cells
  • Found in cytoplasm
  • Get their instruction from hereditary material
    that tells them how, when and in what order to
    make specific proteins

23
Membrane-bound Organelles
  • Organelles are structure in cytoplasm that carry
    out life functions in cells
  • Found in cytoplasm of eukaryotic cells
  • Nucleus is largest organelle
  • Ribosomes are not membrane bound but are
    considered an organelle

24
Organelles that produce Energy
  • Chloroplasts (organelle found in plants)
  • Contain chylorophyll (green pigments) that
    captures sunlight to make sugars called glucose
  • Captured light energy is stored in glucose as
    chemical energy where plants utilizes glucose to
    carry out life functions in cells

25
Organelles that produce Energy
  • Organelle that releases energy is Mitochondria
  • Food (glucose and carbohydrates) is broken down
    into CO2 and H2O and releases energy
  • Sometimes called the powerhouse organelle
    because it provides the energy for cells
  • All plants and animal cells have these

26
Organelles that process, transport and store
materials
  • Endoplasmic reticulum (ER) takes up considerable
    amount of space that process and move materials
    around cell like a conveyor belt
  • Rough ER contains ribosomes where protein is made
    and moved in cell
  • Smooth ER process lipids and oils that store
    energy

27
Organelles that process, transport and store
materials
  • After proteins is made they are transferred to
    Golgi bodies where they are packaged and moved to
    areas of cells in vesicles
  • Materials are also moved to outer membrane for
    release outside of cell
  • Vacuoles also are organelles that store water,
    waste products, food and other cell materials

28
Organelles that Recycle
  • Lysosomes are structures that break down food
    molecules, cell waste, worn-out cell parts and
    viruses
  • Chemicals released from lysosomes break down food
    and dead cells
  • These chemicals are contained in lysosomes and
    when a cell dies, the chemicals are released and
    break down the dead cell

29
Many Celled Organisms
  • Many celled organisms rely of other cells to
    perform all life functions
  • Tissue is a group of similar cells that work
    together to do one job
  • Tissues are organized into organs.
  • Organs are a group of tissues that work together
    to perform a function (heart..nerve, blood and
    cardic muscle tissue)
  • Group of organs working together perform a
    certain function is an organ system
  • Organ systems work together to make up many
    celled organisms (heart, arteries, veins, and
    capillaries)

30
Virusessection 4
  • Viruses causes many diseases
  • Viruses are non-living strands of hereditary
    material surrounded by a protein coat
  • Do not have nucleus, other organelles or a cell
    membrane
  • Viruses rely on host cells to live inside (living
    cells)
  • Have two kinds of viruses Active and Latent

31
Active Viruses
  • Occurs when virus enters host cell and
    immediately begins to make new viruses
  • Destroys the host cells when it makes new viruses
  • Virus uses host cell to duplicate its hereditary
    material and later releases duplicated virus and
    kills host cell when they are released
  • Figure 17 page 232

32
Latent Viruses
  • Some viruses enter host cell and remain inactive
    for a period of time
  • Does not immediately cause the host cell to
    duplicate new virus
  • At a later time it may begin to duplicate and
    release new viruses that kill the host cell
  • AIDS, cold sores are examples

33
How do viruses affect organisms
  • Viruses attach specific cells that match host
    cells
  • Many times viruses only attach to certain host
    cells (potato leafroll)
  • Some viruses can affect numerous organisms
    (rabies)
  • Viruses are moved by wind and inhaled where they
    attach
  • Figure 18 page 233

34
Treating/Preventing Viral Diseases
  • Treatment difficult because antibiotics do not
    kill viruses
  • Prevention is best method of avoiding viral
    infections (eliminate mosquito to fight yellow
    fever)

35
Natural Immunity
  • Human bodies fight viral infections by making
    interferons
  • Interferons are proteins that make a protective
    covering for cells that are infected (produced by
    healthy cells to protect affected cells)

36
Vaccines
  • Vaccines are weakened viruses that cant enter
    host cells and duplicate, but cells begin to make
    interferons that protect all cells from infection
  • Measles, mumps, small pox, chicken pox, polio,
    and rabies
  • Found vaccine by taking weakened cow pox cells
    and entering them into healthy people to prevent
    small pox (1786) Jenner

37
Virus Research
  • AIDS is a disease that is caused by human
    immuno-deficiency virus (HIV)
  • AIDS (acquired immune deficiency syndrome)
  • The HIV virus weakens the immune system and body
    cant fight infections like pneumonia, TB
  • People usually die from weakened system rather
    than disease
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