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Characteristics of Living Things

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Title: Characteristics of Living Things


1
The Keys to Life Characteristics of Living
Things
2
What is Life?
  • "In an organism, a condition in which there is
    reproduction, growth, development, metabolism,
    use of energy, excretion, response to stimuli and
    composition of cells."

3
Characteristics of Living Things
  • Made up of units called cells
  • Grow and develop
  • Maintain a stable internal environment
    homeostasis
  • Respond to the environment
  • Can reproduce
  • Obtain and use materials and energy
  • Taken as a group, change over time (evolution)
  • Based on a universal genetic code (DNA)

4
Cell Structure and Function
  • Cells have specialized structures that carry out
    the cells life processes

5
Cells Make Up Organisms
  • Cells have specialized structures that carry out
    the cells life processes
  • Two types of organisms Prokaryotic Eukaryotic
  • Prokaryotes
  • lack membrane bound organelles
  • Eukaryotes
  • contain membrane bound nucleus and organelles

6
(No Transcript)
7
Cell Theory
  • Formed from the works of Hooke, van Leeuwenhoek,
    Schleiden, Schwann, Virchow
  • Three main premises
  • All living things are made up of at least one
    cell.
  • Cells are the basic unit of structure and
    function
  • All cells come from existing cells

Return
8
Reproduction
  • All species of organisms have the ability to
    reproduce
  • Organisms reproduce like organisms.
  • Life comes only from life. -- BIOGENESIS
  • Two Types sexual and asexual
  • Sexual-involves 2 parts of one
  • organism or from 2 different
  • organisms of the same species
  • Asexual-does not combine heredity info from
    different organisms of the same species


9
Reproduction
  • Transmission of hereditary information (DNA) to
    offspring
  • Essential for the continuation of a species
  • DNA deoxyribonucleic acid
  • Shape double helix
  • Composed of nucleotides


10
Reproduction
  • Nucleotide consists of sugar, phosphate group and
    base
  • Uprights of ladder are alternating deoxyribose
    units and phosphate groups 4 bases make up
    rungs adenine, thymine, cytosine, and guanine
    A---T, C---G
  • Read in 3 letter combos at a time -- CODONS


11
Structure of DNA nucleotides are repeating
units
Return
12
Growth and Development
  • All living things grow
  • Growth is a result of cell division and cell
    enlargement
  • To grow is to change in size.
  • Cell division is the formation of 2 or 4 cells
    from an existing cell (mitosis and meiosis)
  • Newly divided cells enlarge to the size of a
    mature cell

13
Growth and Development
  • An adult organism arises from the process of
    development
  • Occurs due to repeated cell divisions and cell
    differentiation
  • To develop is to change in shape and form.

Return
14
Obtain Materials and Using Energy
  • How organisms obtain, use, and transfer energy
    for life
  • All living things use energy in a process called
    metabolism
  • The sum of all the chemical
  • processes that occur in the organism

15
Obtain Materials and Using Energy
  • Two basic pathways
  • 1. Cellular respiration takes in food, breaks
    it
  • down into glucose, converts to ATP
    (energy)
  • 2. Photosynthesis uses sunlight, water, and
  • carbon dioxide to make glucose (then, the
  • photosynthetic organisms go through
    cellular
  • respiration)

16
Obtain Materials and Using Energy
  • Almost all energy for life on earth derived from
    photosynthesis
  • Autotrophs produce their own energy by making
    their own food
  • EX. Plants
  • Heterotrophs must take in food to meet energy
    needs
  • EX. Herbivores, carnivores, omnivores,
    scavengers, detrivores

17
Obtain Materials and Using Energy
  • Living things are set apart by their complexity
  • All living things are highly organized at both
    the molecular and cellular levels
  • Most multicellular organisms have cells and
    groups of cells organized by function

Return
18
Environmental Response
  • Response a reaction to a stimulus
  • Ex. Plant responding to light will move its
    leaves to maximize exposure for photosynthetic
    processes.

Boy, that water sure looks cool and refreshing
Return
19
Homeostasis
  • Organisms are looking for HOMEOSTASIS
  • process where organisms try to reach a steady
    state or balance
  • Please add this comment to your notes as it is
    not on your handout!

20
Homeostasis
  • All living things maintain stable internal
    conditions
  • Includes regulation of temp, water content, food
    intake, etc.
  • Most multicellular organisms have gt1 systems
    maintains important internal controls
  • Keep in mind that living orgs NEVER reach a
    perfect balance it is a constant balancing act
    of overshooting and undershooting the goal

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21
Change over time -- Evolution
  • Change over time evolution
  • EVOLUTION is the gradual accumulation of
    adaptations over time that help a group of
    organisms survive and be able to produce new
    offspring that would demonstrate the BEST
    combination of adaptations
  • SURVIVAL OF THE FITTEST!!!

22
Change over time -- Evolution
  • Populations of organisms gradually change
    (evolve) over generations
  • Process of natural selection important to
    evolution process
  • Survival of the fittest
  • Survivors pass favorable traits on to offspring

23
Changes in beetle populations over time
24
Evolutionary benefits can be due to better
camouflage
Return
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