Transcript Three Domains of Life

Unit 4:
Classification of Living Things
Characteristics of Living Things
• All living things:
1. Have Cellular Organization
2. Share Chemicals of Life
3. Need Energy
4. Respond to Surroundings
5. Grow and Develop
6. Reproduce
Cellular Organization
• Cell- The basic unit of structure
and function in an organism
• Unicellular- single celled
• Multicellular- many cells
Chemicals of Life
• Carbohydrates- also called sugars,
used for energy
• Proteins- building material of cells
• Lipids- building material of cells
• Nucleic Acids- genetic material,
gives cell instructions and controls
cell’s activities
Energy Use
• Cells need energy to function and
repair themselves!
• The sun is the ultimate source of
energy for all life on earth.
Response to Surroundings
• Stimulus- a change that causes an
organism to react (ex: temp, light,
sound)
• Response- an action or change in
behavior…happens because of
stimulus
Growth, Development,
Reproduction
• Growth- getting larger
• Development- becoming more complex
• Reproduction- passing on genetic
material
Life Comes From Life
• Spontaneous Generation- living
things can arise from nonliving
things- HAS BEEN DISPROVEN
• It took hundreds of years and lots of
experiments to prove this
Life Comes From Life
• Francesco Redi
designed one of
the first
controlled
experiments. In
his experiment,
Redi showed that
flies do not
spontaneously
arise from
decaying meat.
Life Comes From Life
• Louis Pasteur’s
carefully
controlled
experiment
demonstrated
that bacteria
arise only from
existing
bacteria.
The Needs of Living Things
1. Water- can only live a few days
without water. Need it to obtain
chemicals, digest, grow, move, and
reproduce
2. Food- Used for energy source
a. Autotrophs- Make their own
energy using sunlight (plants)
b. Heterotrophs- Obtain food by
eating other organisms
The Needs of Living Things
3. Living Space- organisms compete for
space and resources
4. Stable Internal Conditions
a. Homeostasis- maintaining stable
internal conditions so cells can
properly function (our body temp)
Classification
• Scientists classify so we can make
sense of the world and living things,
makes living things easier to study.
• Classification- the process of grouping
things based on their similarities
• Taxonomy- the scientific study of
how living things are classified
Classification
• Binomial Nomenclature- Created by
Linneaeus, 2-part naming system. Uses
Genus and Species. Ex: Homo sapiens
• Genus- contains similar, closely-related
organisms. Pumas and house cats are in
Genus Felis. They have sharp,
retractable claws, and hunt.
• Species- group of similar organisms that can
mate with each other and produce viable
offspring
Classification
Levels of Classification- The more levels that
2 organisms share, the more
characteristics they have in common
Kingdom
Phylum
Class
Order
Family
Genus
Species
Levels of Classification
• As you move down the levels of classification, the
number of organisms decreases. The organisms at
lower levels share more characteristics with each
other.
Terms
• Prokaryotes- Don’t have a nucleus
• Eukaryotes- have a nucleus
• Autotrophs- Make food from sun
• Heterotrophs- obtain food from
eating autotrophs and other
heterotrophs
Cell Wall- rigid layer of material that surrounds
some cells to provide protection & support
(plants, fungi, bacteria)
plant
bacteria
animal
No cell wall
Three Domains of Life
In the three-domain system of classifications,
all known organisms belong to one of three
domains–Bacteria, Archaea, or Eukarya.
Bacteria
(Prokaryotes, Autotrophs
& Heterotrophs, Cell
Walls)
Kingdom: Eubacteria
On your body, in
foods we eat. Most
aren’t harmful.
Three Domains of Life
Archaea
(Prokaryotes, Autotrophs
& Heterotrophs, Cell
Walls)
Eukarya
(Eukaryotes)
Kingdom: Archaebacteria
Kingdoms:
Protists- Can’t be classified as
anything else. Very Diverse.
salty, etc). Archaea means
“ancient” in Greek.
Auto/heterotrophs,
uni/multicellular. Seaweed,
Paramecium
Live in extreme
environments (dark, hot,
(NO Cell Walls)
Fungi- Mushrooms, molds,
mildew. Most are multicellular.
Heterotrophs. (Cell Walls)
Absorb nutrients from decaying
organisms.
Plants- trees, moss, peas.
Multicellular. (Cell Walls) Most
live on land. Autotrophs. Very
diverse.
Animals- Multicellular.
Heterotrophs. (NO Cell Walls)
Very diverse.
Taxonomic (Dichotomous) Key
• Keys are used to determine the
identification of organisms.
• Statements are in pairs