Characteristics of Living
Systems
Living Systems
• Biology
- The science of life and all living organisms,
including their structure, function, growth, origin,
evolution, and distribution. It includes botany
and zoology and all their subdivisions.
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BOTANY – study plants
ZOOLOGY – study animals
PALEONTOLOGY – study past (ancient) life forms
ECOLOGY – study of life and surroundings
(environments)
Living Systems
1. All organisms are composed of one or more
cells
2. All organisms are able to grow, reproduce and
adapt
3. All organisms use energy
4. All organisms maintain homeostasis
5. All organisms respond to the environment
6. All organisms receive instructions from DNA
1. Cell Theory
• All living things are made up of cells.
• Cells are the smallest working units of
all living things.
• All cells come from preexisting cells
through cell division.
Definition of Cell
A cell is the smallest unit that is
capable of performing life
functions.
Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
Two Types of Cells
•Prokaryotic
•Eukaryotic (animal cells)
2. Adaptation
• Any structure, behavior, process that
promotes survival of a species.
– Cactus – have thorns
– Camels – have humps of FAT on their backs
– Camels foot – webbed to trek terrain
3. Organisms use energy
All Life needs energyphotosynthesizers use solar energy,
(autotrophs)
chemosynthesizers use chemical energy,
(autotrophs)
Most other organisms use the energy stored
as the bodies of the these two.
(heterotrophs)
4. Homeostasis
• Steady state of being regardless of
external surroundings.
• Maintaining a stable internal environment
– Shiver when cold.
– Sweat when hot.
5. Environment- surroundings
• Biotic factors – all things alive
or that once lived.
• Abiotic factors – all things
that never lived but affect life.
6. Instructions from DNA
• Every living thing has DNA. That
means that you have something in
common with a zebra, a tree, a
mushroom and a beetle!!!!
Classification
• Taxonomy naming system for the
organization of life.
– Grouping or categorizing based on similarities
Modern classification began with the work of Carolus Linnaeus,
who grouped species according to shared physical characteristics.
In the life sciences, binomial nomenclature is the
formal method of naming species. As the word
"binomial" suggests, the scientific name of a species
is formed by the combination of two terms: the genus
name and the species descriptor.
Classification of living systems
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Kingdoms
Phylum
Class
Order
Family
Genus
Species
Classification
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6 KINGDOMS
Animalia
Plantae
Fungi
Protista
Prokaryotes
Eukaryotes
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Used to be 1 kingdom- Monera (Bacteria only)
• Viruses are not classified as living. Viruses do however
demonstrate reproductive capabilities like living things. They
are smaller than bacterial cells!
The 6 kingdoms
• Prokaryotes (Used to be 1 kingdom,
Monera)
– Archaebacteria
– Eubacteria
• Eukaryotes
– Fungi
– Protista
– Animal
– Plantae
Overview of the 6 kingdoms
• Archaebacteria
– Unicellular
– Live in extreme environments
– Prokaryotic
• Eubacteria
– Unicellular
– Prokaryotic
– “Common bacteria”
Overview of the 6 kingdoms
• Protista
– Eukaryotic
– Unicellular or colonial
– Lots of different life styles
• Fungi
– Cell walls made of chitin
– Eukaryotic
– Multicellular
– External heterotrophs
Overview of the 6 kingdoms
• Plantae
– Eukaryotic & Multicellular
– Cell walls made of cellulose
– Autotrophic
• Animalia
– Eukaryotic & Multicellular
– No cell walls
– Internal heterotrophs
•Let’s look at an
example!
What is my name?
Puma ?
What is my name?
Devil Cat ?
Ghost Cat ?
What is my name?
My real name is
Puma concolor
What is my name?
Binomial Nomenclature
• There are at least 50 common names
for Puma concolor.
• Common names vary according to
region, country or language.
• Soooo……why use a scientific name?
Binomial Nomenclature
Two name system for writing scientific names.
•The genus name is written first (always
Capitalized).
•The species name is written second (never
capitalized).
•Both words are italicized if typed or underlined if
hand written. The name is also in Latin (a dead
language).
Binomial Nomenclature
• More examplesGenus and species
Common name
Range
Panthera leo
Lion
Africa (Asia)
Panthera onca
Jaguar
N. & S. America
Panthera pardus
Leopard
Africa, Asia, Europe
Panthera tigris
Tiger
Asia
How many organisms are out
there?
• Scientists currently estimate that
– There are 10 million species worldwide
– Over 5 million live in the tropics
– Most unnamed species are small or
microscopic
Why is taxonomy useful?
• Helps prevent confusion among
scientists
• Helps to show how organisms are
related
• Can be used to reconstruct phylogenies
– evolutionary histories – of an organism
or group
Organization of LIFE
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CELL – BASIC UNIT OF LIFE
TISSUE- MANY CELLS
ORGANS- MANY TISSUES
ORGAN SYSTEMS-GROUPED ORGANS
ORGANISMS – CONTAINS ORGAN
GROUPS
• SPECIES- GROUPS OF THE SAME
ORGANISM