Characteristics of Living
Things
Grade 6
What is biology?
The study of
living things
All living things
share certain
characteristics
What is Living and What is
Not???
Trying to determine if something is alive can be a
little tricky. If you walk up and kick a tree trunk,
nothing happens. No 'Ouch!' from the tree, and it
won't run from you. A tree won't eat a cheeseburger
out of your hand the way a dog might, or make waste
that you have to clean up in the yard. Some living
things appear to be non-moving and unresponsive to
the environment at first glance. Scientists have come
up with traits that all living things have in common.
They help determine whether something is living or
nonliving.
1. Made of 1 or more cells
The first of these traits is that a living
thing is made up of cells. A cell is the
smallest unit of structure and function
in something that lives. And even an
organism made up of only one cell still
meets the criteria for being a living
thing. Cells are extremely tiny, and
cannot be seen by the unaided human
eye.
Unicellular (one cell)
- ex. Bacteria
Multicellular (many cells)
- ex. Animals, plants
2. Nutrition
Second, organisms use energy and can get
energy from a source. Living things use energy
within their cells. This energy powers all kinds of
processes, such as reproduction, growth, or body
temperature regulation. Some living things take in
nutrients, such as eating food or absorbing materials
through roots or a cell membrane. Other living things
get energy from the sun. The complex relationships
between many organisms in an environment allow for
energy to be passed between them.
2. Nutrition
Autotrophs - get
energy from sun
Heterotrophs - get
energy by
consuming
nutrients from their
environment
3. Respiration
All living things need energy. They get this
energy from the food they eat.
The process of getting energy from food is a
chemical reaction called respiration.
Respiration usually needs oxygen ( but it can
happen without oxygen in some organisms).
Food + Oxygen  Carbon dioxide+ water +
energy
4. Excretion
Excretion means getting rid of the waste
materials that can harm the body. Many of
these waste products are made by chemical
reactions that take place inside the body.
If the waste products are not excreted, they
build up in the body and they can cause the
animal or the plant to die.
5. Movement
The next trait is movement. Some
organisms move in a very obvious way,
such as a running animal or a sprouting
seed. Other living things move in a way that
is more difficult to detect. Technological
devices, such as a microscope or camera,
may be needed over a long period of time
to be able to observe movement.
6. Respond to stimuli in their
environment
Stimuli - factors in
the environment that
living things react to
(ex. Light,
temperature, sound,
etc.)
6. Respond to stimuli in their
environment
Living things respond and adapt to their
environment. Many experiments have been done
with plants to show how they grow towards light, also
known as phototropism. This special ability allows the
plant to maximize sunlight exposure necessary for
growth. Other organisms have unique ways to handle
extreme environments, like a leaf with a waxy cuticle
that helps a plant retain water in the desert. Some
responses are easy to observe, such as the pupil of
an eye that constricts when a light is shone into it.
7. All living things reproduce
Another characteristic of a living thing is reproduction.
Reproduction is the passing on of genetic information to a
new generation. You are probably familiar with how human
and mammal reproduction works. It takes two to tango.
Sexual reproduction is when DNA from two separate
organisms combines to form a unique new individual.
Some living things reproduce asexually, meaning they
make an identical copy of their DNA, which carries genetic
instructions that help create a new living form.
Asexual reproduction could look like a single-celled
organism splitting into two, or a mold sending spores out
into the surrounding area.
7. All living things reproduce
Sexual - two
sex cells
required
(sperm and
egg)
Asexual - only
one parent cell
is needed
8. Grow and develop
Living organisms also grow and develop. A
baby develops in a mother's womb. At first, it
looks like just a mass of cells, but over time
the head, limbs, and specific organs form
and grow. Likewise, a seed begins its life just
under the soil and, over time, forms into a
plant and grows up through the soil towards
the sun.
8. Grow and develop
Each cell divides to
make new cells (cell
division) – results in
growth
Some cells become
specialized and
perform different
jobs than others
(differentiation)
9. Maintain homeostasis
Homeostasis – a
relatively stable
internal environment
(within a certain
range)
- (ex. Human body
temperature
(approximately 98.6
degrees F))
10. Have a universal genetic
code
All living things
have DNA
DNA passes on
genetic
information from
one generation to
the next
For each behavior in the list below, write down one or
more correct characteristics of living things from the box
underneath.
Smelling food
Escaping from danger
Producing fruit
Hearing noise
Giving birth to a baby
Lifting a heavy object
Chewing grass
Getting taller
Using oxygen to release
energy
Sweating
Eating an apple
Feeling tired because you
have run fast
Laying eggs
Urinating
Forming new plantlets
Bending towards sunlight
Nutrition
respiration excretion
reproduction
sensitivity
growth
movement