Characteristics of Living Things

1
Characteristics of Living Things

• Made up of units called cells
• Reproduce
• Based on a universal genetic code DNA or RNA
• Grow and develop
• Obtain and use materials and energy
• Respond to the environment
• Maintain a stable internal environment -
  homeostasis
• Taken as a group, change over time - evolve

2
Cells are Basic Units of Structure and Function

• Cell theory Hooke (cork), van Leeuwenhoek
  (first living cells?),
• Schleiden, Schwann, Virchow
• Prokaryotic vs. eukaryotic
• Prokaryotic no nucleus or membrane-bound
  organelles
• Eukaryotic nucleated with membrane-bound
  organelles

3
Eukaryotic vs. Prokaryotic Cell
4
Reproduce

• Organisms reproduce like organisms.
• Life comes only from life. -- BIOGENESIS

5
All living things reproduce
6
DNA Code of life

• Double helix composed of nucleotides
• Nucleotide consists of sugar, phosphate group and
  base
• Uprights of ladder are alternating ribose 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

7
Structure of DNA nucleotides are repeating units
8
Growth and Development

• Grow is to change in size.
• Develop is to change in shape and form.
• DNA directs patterns of growth and
  development.

9
(No Transcript)
10
Obtain materials and use energy

• Producers (autotrophs) plants or any other
  organism that can make its own food sources.
• EX. Plants -- photosynthesis
• Consumers (heterotrophs) any organism that must
  consume another organism for food.
• EX. Herbivores, carnivores, omnivores

11
(No Transcript)
12
Use Energy

• 2 basic pathways
• 1. Cellular respiration takes in food,
  breaks it down into glucose, converts to
  ATP (bodys gasoline)
• 2. Photosynthesis uses sunlight, water, and
  carbon dioxide to make glucose (then, the
  photosynthetic orgs go through cellular resp.)

13
Environmental Response

• Response a reaction to a stimulus
• Ex. Get cold, put on a jacket

14
Boy, that water sure looks cool and refreshing
15
Maintain a stable internal environment

• Organisms are looking for HOMEOSTASIS
• -- process where organisms try to reach a
  steady-state or balance
• Keep in mind that living orgs NEVER reach a
  perfect balance it is a constant balancing act
  of overshooting and undershooting the goal

16
Change over time -- evolution

• Evolve means to change over time
• 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!!!

17
Changes in beetle populations over time
18
Evolutionary benefits can be due to better
camouflage