Download Science 8 Unit B – Section 1.0

Science 8 Unit B – Section 1.0
Living things share certain characteristics and
have structures to perform functions
Section 1.0 Outcomes
Describe the characteristics of living things
 Analyze the general structure and function of
living things
 Explain how living things have different
structures for similar functions
 Show how the body is organized into
systems

1.1 – The Characteristics of Living
Things
There are many types of living things – from
simple single-celled organisms to complex
multicellular life forms
 However, they all share 6 characteristics:

1. Living things are made of cells

Cell:
Every organism is made up of at least one
cell
 Every cell must come from another cell

2. Living things use energy
Organisms require energy to carry out a
number of processes
 The way that the energy is gathered can
vary, but all living things do require energy
 As well, living things require nutrients to grow
 Metabolism:

3. Living things respond to the
environment
Every organism shows a response to various
types of stimulus
 Stimulus:

4. Living things grow and develop
All living things both grow and develop over
their lifetime
 Growth involves a simple change in size of
the organism
 However, many organisms develop, which
means that their body shape may change
drastically over time

5. Living things reproduce
All living things must come from other living
things
 This is known as reproduction
 Reproduction is not necessary for an
organism to survive, but without reproduction
a species will not survive

6. Living things have adaptations
for their environment

Adaptation:

Adaptations make it easier for a particular
organism to survive long enough to
reproduce
Viruses & Prions – Living or Not?
A virus is a strand of DNA that is wrapped
within a protein shell
 Viruses enter host cells and use their cellular
machinery to reproduce more virus particles
 Prions are proteins that interact with host
cells and cause diseases

1.2 – Structure and Function
Living things need to carry out a number of
tasks to survive
 Some tasks are common to almost all
organisms, while some tasks are specific to a
few (or even a single) species

Structure vs. Function

Structure:

Function:
Different structures, same function

Some organisms use different structures to
carry out the same function
Variation in Structures
Often variation in structure is due to the
environment in which an organism is found
 However, the variation is not caused by the
environment
 The variations occur through random
mutations and those that give organisms an
advantage are passed on

Darwin’s Finches
Each of the finches on the Galapagos islands
developed over time to have a beak shape
that matched the most abundant type of food
on each island
 This happened when birds who were born
with the correct beak shapes outcompeted
other birds and reproduced, passing on their
beak shapes

1.3 – Organs and Organ Systems
There are a number of levels of organization
within the human body
 The lowest level is the individual cell
 Collections of similar cells make up tissues
 Collections of tissues that work to perform a
task are known as organs
 Groups of organs that carry out a similar task
are known as organ systems

Ex: The digestive system
At a cellular level, a vast number of different
cells make up the digestive system
 These cells form epithelial, muscle,
connective, and nervous tissue
 These tissues form organs such as the
stomach, intestines, esophagus, and other
organs
 All of these organs together make up the
digestive system

The Circulatory System

Structures:
Used to transport oxygen, food, and other
substances
 Defends the body against diseases

The Respiratory System

Structures:

Exchanges oxygen and carbon dioxide
between the outside air and the blood
The Digestive System

Structures:

Breaks down food into particles that can be
absorbed and transported throughout the
body
The Nervous System

Structures:
Coordinates and controls the actions of all
organs and organ systems
 Detects, processes and responds to changes
in external and internal environments

The Excretory System

Structures:

Removes chemical and gaseous wastes
from the blood
The Skeletal System

Structure
Provides a movable support frame for the
body
 Protects soft-tissue organs

The Muscular System

Structures:
Moves bones
 Moves organs that contain muscle tissue

The Integumentary System

Structures:
Protects the body’s internal environment from
the external environment
 Sense pain, pressure, and temperature
