Living Things
Table of Contents
What Is Life?
Classifying Organisms
Domains and Kingdoms
The Origin of Life
Living Things
What is an Organism?
-An organism is a complete and whole living thing.
*All organisms share six important characteristics.
Living Things
1. Made of Cells
*A cell is the basic unit of structure
and function in a living organism.
*Unicellular organisms are made of
a single cell—like a bacteria cell.
*Multicellular organisms
are made of many cells-like an elephant.
Living Things
2. Contain similar chemicals
-Cells of living things are made mostly of five basic
chemicals.
*Water—most abundant
*Carbohydrates —for energy
*Proteins and Lipids—building materials
*Nucleic acids—genetic material
Living Things
3. Use Energy
-All organisms use energy to
carry out their daily activities.
*We need energy to move,
think, digest food, repair cell
damage, etc.
Living Things
4. Respond to Surroundings
-All organisms react to changes in their environment.
*Stimulus—something that
causes and organism to react.
(a sight, sound, smell, touch
or taste).
Here the stimulus is the sight of the fly.
*Response—how an organism
reacts or behaves to the change.
The response is catching the fly.
Living Things
5. Grow and Develop
-All living things grow and develop.
*Growth—living things increase in size.
*Development—the process of change that
occurs as an organism grows, producing a
more complex organism.
Living Things
6. Reproduce
-All living things produce offspring similar to themselves.
Living Things
Where does Life Come From
-Four hundred years ago, people believed that living
things could come from nonliving material.
This idea was called Spontaneous Generation.
-Two scientists, Francesco Redi and Louis Pasteur
worked to prove that this theory was incorrect.
Living Things - What Is Life?
Redi’s and Pasteur’s Experiments
Click the Active Art button to open a browser window
and access Active Art about Redi’s and Pasteur’s
experiments.
Living Things - What Is Life?
Life Comes From Life
In 1668, Francesco Redi
designed one of the first
controlled experiments.
In his experiment, Redi
showed that flies do not
spontaneously arise from
decaying meat.
Living Things - What Is Life?
Life Comes From Life
Nearly 200 years later, in
1864, Louis Pasteur’s
carefully controlled
experiment demonstrated
that bacteria arise only
from existing bacteria.
Living Things
Biogenesis replaces Spontaneous Generation
-In 1870, Thomas Huxley developed the theory of
Biogenesis to replace Spontaneous Generation.
*It states: living things arise from living things through
reproduction.
Bio = life
Genesis = beginning
Living Things
The Needs of Living Things
-All living things have the same basic needs:
Water
Food
Living Space
Makes-up 70% of
most living things
Autotrophs—make their own food
Organisms need
a place to live
Stable Internal Conditions
(homeostasis)
Heterotrophs—can not make food
Heterotrophs vs. Autotrophs
Flipchart activity
Organisms must
be able to keep
conditions inside
their bodies constant
Living Things - What Is Life?
The Characteristics of Living Things
Click the Video button to watch a movie about the
characteristics of living things.
Living Things - What Is Life?
Using Prior Knowledge
Look at the section headings and visuals to see what this
section is about. Then write what you already know about
living things in a graphic organizer like the one below. As you
read, write what you learn.
What You Know
1.
2.
Living things grow.
Living things are made of cells.
1.
2.
3.
What You Learned
Unicellular organisms are composed of only one cell.
The cells of living things are composed of chemicals.
The cells of organisms use energy to do things they must do.
Living Things
End of Section:
What Is Life?
Living Things
Classifying Organisms
-Classification is the process of
grouping things based on their
similarities.
-Taxonomy is the science of
classifying living things.
Living Things - Classifying Organisms
Aristotle and Classification
Many hundreds of years before
Linnaeus, a Greek scholar
named Aristotle developed a
classification system for
animals. Aristotle first divided
animals into those he
considered to have blood and
those he did not. This graph
shows Aristotle’s classification
system for “animals with blood.”
Living Things - Classifying Organisms
Aristotle and Classification
Reading Graphs:
Into how many groups
were these animals
classified?
3
Living Things - Classifying Organisms
Aristotle and Classification
Interpreting Data:
Which group made up the
largest percentage of
animals?
Animals that fly
Living Things - Classifying Organisms
Aristotle and Classification
Calculating:
What percentage of these
animals either fly or
swim?
78%
Living Things - Classifying Organisms
Aristotle and Classification
Inferring:
In Aristotle’s classification,
where would a cow be
classified? A whale?
Cow- animals that walk, run,
or crawl; whale- animals that
swim.
Living Things - Classifying Organisms
Aristotle and Classification
Predicting:
Would Aristotle’s
classification system be
used today? Explain.
Possible answer: This system
includes only three categories, so it
may not be very useful today. It also
does not match that of modern
scientists, who use characteristics
other than movement to classify
animals. For example, frogs
and lions belong to
very different groups.
Living Things
The Naming System of Linnaeus
-In the 1750s Swedish
scientist, Carolus Linnaeus
developed the system of
naming living things called
binomial nomenclature.
*Each organism is given a
unique, two-part name made
up of its genus and its species.
*Example: Felis domesticus
(house cat)
Living Things
Levels of Classification
-Today, organisms are grouped together based on shared
characteristics into various levels. The largest level is
called the Domain.
-A domain is then divided into: kingdom, phylum, class,
order, family, genus and species levels.
*Use this to help you remember the correct order :
“Didn’t King Phill Come Over From Great Spain?”
“Don’t Kids Prefer Candy Over Fresh Green Salad?”
Living Things - Classifying Organisms
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.
Living Things
Species
Group
Name
Human
Chimp
Cat
Lion
Fly
Kingdom
Animalia
Animalia
Animalia
Animalia
Animalia
Phylum
Chordata
Chordata
Chordata
Chordata
Arthropoda
Class
Mammalia
Mammalia
Mammalia
Mammalia
Insecta
Order
Primates
Primates
Carnivora
Carnivora
Diptera
Family
Hominidae
Pongidae
Felidae
Felidae
Muscidae
Genus
Homo
Pan
Felis
Panthera
Musca
Species
sapiens
troglodytes
domestica
leo
domestica
Scientific
name
Homo
sapiens
Pan
troglodytes
Felis
domestica
Panthera
leo
Musca
domestica
Living Things - Classifying Organisms
Taxonomic Keys
Taxonomic keys are useful tools for determining the
identity of organisms.
Living Things
What is it????
Living Things - Classifying Organisms
Evolution and Classification
Species with similar evolutionary histories are classified more
closely together. These Galapagos finches may have arisen from a
single species and changed gradually over time to become three
separate species. Notice the differences in their appearance,
especially their beaks.
eats
eats
eats
Living Things - Classifying Organisms
Asking Questions
Before you read, preview the red headings. In a graphic
organizer like the one below, ask a what, why, or how
question for each heading. As you read, write the answers to
your questions.
Question
Why do scientists classify?
Answer
Scientists classify because they want
to organize living things into groups
so they are easier to study.
What system did Linnaeus use to
name organisms?
He used a system called binomial
nomenclature.
What are the levels of classification?
Domain, kingdom, phylum, class,
order, family, genus, species
Living Things - Classifying Organisms
More on Classifying Living Things
Click the PHSchool.com button for an activity about
classifying living things.
Living Things
End of Section:
Classifying
Organisms
Living Things - Domains and Kingdoms
Three Domains of Life
In the three-domain system of classifications, all known
organisms belong to one of three domains–Bacteria,
Archaea, or Eukarya.
Living Things
Domains and Kingdoms
-Organisms are placed into domains and kingdoms
based on their cell type, the number of cells in their
bodies, and their ability to make food.
*Note: Cell type is either: eukaryotic—with a nucleus
or
prokaryotic—without a nucleus
Bacteria—prokaryotic, single cells. Some can make food and
some can not.
Archaea—prokaryotic, single cells. Some can make food and
some can not. The difference is they do NOT need oxygen to live.
Eukarya—eukaryotic cells. Divided into four kingdoms: Protists,
Fungi, Plants and Animals.
Living Things - Domains and Kingdoms
Comparing and Contrasting
As you read, compare and contrast the characteristics of
organisms in domains Bacteria, Archaea, and Eukarya by
completing a table like the one below.
Characteristics of Organisms
Domain or Kingdom
Cell Type and Number
Able to Make Food?
Bacteria
Prokaryotes; unicellular
Some are able to make food
Archaea
Prokaryotes; unicellular
Some are able to make food
Some are able to make food
Plants
Eukaryotes; unicellular or
multicellular
Eukaryotes; unicellular or
multicellular
Eukaryotes; multicellular
Animals
Eukaryotes; multicellular
No
Eukarya:
Protists
Fungi
No
Yes
Living Things - Domains and Kingdoms
Links on Kingdoms
Click the SciLinks button for links on kingdoms.
Living Things
End of Section:
Domains and
Kingdoms
Living Things
The Origin of Life
-If living things come only
from other living things
then….
-where did the first living
thing come from?
-Scientists have a
theory…
Living Things - The Origin of Life
The Atmosphere of Early Earth
On ancient Earth, water vapor, carbon dioxide,
and methane were probably the most abundant
gases in the atmosphere. There were frequent
volcanic eruptions, earthquakes, and violent
storms. There was no oxygen in the
atmosphere. Most of the living things present
today could not have survived these conditions.
Living Things
Life on Early Earth
-A Russian scientist, Alexander Oparin, suggested that over
millions of years, chemical elements and compounds joined
together under these very different conditions to form
proteins—the building blocks of cells.
-Eventually, these could copy themselves and use other
chemicals for food.
-They evolved into the first living cells about 3.5 - 4.0 billiion
years ago.
Living Things
Evidence for this Theory
-Fossils resembling today’s
archaebacteria have been
discovered dating back to 3.5 billion
years ago.
-American scientists, Stanley Miller
and Harold Urey’s electric spark
experiment in 1953, showed that
substances present in living things
(like proteins) could come from
nonliving material.
-This experiment did not PROVE
that this happened—only that it is a
possibility.
Living Things - The Origin of Life
Identifying Supporting Evidence
As you read, identify the evidence that supports scientists’
hypothesis of how life arose on Earth. Write the evidence in a
graphic organizer like the one below.
Evidence
Hypothesis
Fossil evidence of
achaea-like
organisms
Origin of life
Fossils dated to be
between 3.4 and 3.5
billion years old.
Living Things - The Origin of Life
Links on the Origin of Life
Click the SciLinks button for links on the origin of life.
Living Things - The Origin of Life
Modeling Conditions on Early Earth
Click the Video button to watch a movie about modeling
conditions on early Earth.
Living Things
End of Section:
The Origin of Life
Living Things
Graphic Organizer
Living Things
need
Homeostasis
Food
Living space
Water
made by
to provide
Autotrophs
eaten by
Heterotrophs
Shelter
Food & water
Living Things
End of Section:
Graphic Organizer