Multicellular Organisms

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Multicellular Organisms

• Cell Teamwork
• The Processes of Life

2
Objectives

• At the end of this PowerPoint, you will be able
  to
• Explain the common problems that multicellular
  organisms have.
• Identify body systems in these organisms that
  allow them to function as a multicellular
  organism.
• Show how these complex systems work together to
  carry out the vital functions of life.

3
CONTENTS

• Body Organization
• What Cells Need
• Transportation of Materials
• Obtaining Nutrients
• Gas Exchange
• Excretion
• Movement
• Control
• Protection
• Reproduction

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Body Organization

• At first an organism like a human appears to be
  this complicated pile of organs.
• Those organs make up the organ systems of the
  body.

But first, lets look at how life is organized
from the bottom up.
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Levels of Organization
Organism
Organ System
Organ
Tissue
Cell
Organelle
Molecule
Atom
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How to Be a Multicellular Organism
Lets look at the difficulties in being made up
of more than 1 cell and how the body systems are
organized to make it all work.
CONTENTS
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What Cells Need
Photosynthesis
Respiration

• All cells, whether alone or part of a larger
  organism, do the same processes.

Cell
Mitosis
Building Cells Out of Proteins
CONTENTS
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Unicellular Organisms

• A protist is surrounded by water, food, and
  oxygen.
• Materials just diffuse in and out of the cell.

Oxygen
Nutrients
Protist
Waste
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What Cells Need
Water
Oxygen Gas (O2)
Nitrogen (proteins)

• Thus all cells need the same materials and
• Excrete the same waste products.

Protist
Carbon Dioxide (CO2)
Nitrogen Waste
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Diffusion How Chemicals Move
Water
Oxygen Gas (O2)
Nitrogen (proteins)

• A protist is surrounded by water, nutrients, and
  oxygen.
• Materials just diffuse in and out of the cell.

Protist
Carbon Dioxide (CO2)
Nitrogen Waste
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Diffusion How Chemicals Move
Water
Oxygen Gas (O2)
Nitrogen (proteins)

• A protist is surrounded by water, nutrients, and
  oxygen.
• Materials just diffuse in and out of the cell.

Protist
Carbon Dioxide (CO2)
Nitrogen Waste
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Transportation Needed
Nutrients
Oxygen

• In a multicellular organism, only the outermost
  cells can exchange materials with the outside
  environment.
• These organisms need a way to get materials in
  and out of the inner cells.

?
Waste
CONTENTS
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Transportation Needed

• In some simple organisms like this sponge, water
  with nutrients just flows in and out of the
  organism.

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Transportation Pipes

• In more complicated multicellular organism,
  there are pipes which transport nutrients
  around the body.

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Plant Transportation Systems

• In plants xylem pipes carry water and nutrients
  up from the roots.
• Phloem pipes carry food from the leaf down to
  other cells.

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Animal Transportation Systems

• In animals, blood vessels are the pipes that
  transport food, oxygen, and wastes around the
  body.

Circulatory System
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Animal Transportation Systems

• We also call this system the Cardiovascular
  System.
• cardio- heart (the pump)
• -vascular vessels (the pipes)

Circulatory System
CONTENTS
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Multicellular Organisms Obtaining Nutrients
The Digestive System
Food

• Multicellular organisms (except plants) need food
  for energy.
• They need a system to get food in and broken up
  for the body to use.

Waste (unused food)
CONTENTS
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Animals Obtaining Nutrients
The Digestive System

• Animals have a digestive system which
• Takes in food
• Breaks the food down.
• Gets the digested food into the blood for
  transportation to the cells.

Do plants need a Digestive System?
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• Plants do need
• Sunlight for energy
• Water
• Carbon Dioxide
• Nutrients

NO

• Because plants make their own food through
  photosynthesis, they
• Do not eat and
• Do not need a digestive system.

BUT
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Plants Obtaining Nutrients

• Plants have organs which help them take in
  nutrients and to do photosynthesis
• Roots Absorb (take in) water and nitrogen from
  the soil
• Leaves take in carbon dioxide and carry out
  photosynthesis

• Take in CO2
• Location of photosynthesis

• Absorb water
• Absorb nitrogen

CONTENTS
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Multicellular Organisms Gas Exchange
Oxygen
CO2

• Multicellular organisms need a system to get
  oxygen in and carbon dioxide out of the body.

The Respiratory System
CONTENTS
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Plants Gas Exchange

• Plants also need to exchange gases with the
  atmosphere.
• For Photosynthesis
• CO2 in O2 out
• For Cellular Respiration
• O2 in CO2 out

LEAF
InPhotosynthesis
O2 out
O2 out
CO2 in
CO2 in
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Plants Gas Exchange

• Plants also need to exchange gases with the
  atmosphere.
• For Photosynthesis
• CO2 in O2 out
• For Cellular Respiration
• O2 in CO2 out

LEAF
InRespiration
O2 out
CO2 out
CO2 in
O2 in
CONTENTS
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Multicellular Organisms Excretion
Excretion Getting Rid of Wastes

• Multicellular organisms need a system to get
  poisonous wastes out of the body.

The Urinary System
Waste
CONTENTS
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Multicellular Organisms Excretion
Excretion Getting Rid of Wastes

• Removing carbon dioxide (CO2) from the body is
  also part of excretion.

CO2 out
The Respiratory System
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Excretory System

• We sometimes combine these 2 systems under the
  heading of the Excretory System.

ExcretorySystem
UrinarySystem
RespiratorySystem



CONTENTS
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Unicellular Organisms Movement

• For a protist to move, it simply needs to move
  its one cell.

Protist
CONTENTS
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Multicellular Organisms Movement

• A multicellular organism can only move if every
  cell moves at the same time and in the same
  direction.
• A control system is needed for this to happen.

CONTENTS
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Multicellular Organisms Control

• A multicellular organism needs to have control
  systems to coordinate cells.

Nervous System Electrical Control
Endocrine System Chemical Control
CONTENTS
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Electrical Control Nervous System

• Central Control Brain and Spinal Cord
• Nerves to carry messages

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PLANTS
Why Don't Plants Have a Nervous System?
Sorry, no answer here. Discuss this one with your
group.
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Chemical Control Endocrine System

• Glands produce chemical hormones.
• The blood carries these chemical messages.

What System does the Endocrine System Need to
Work?
Thats right. The Circulatory System The blood is
needed to transport the chemical hormones around
the body.
CONTENTS
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PROTECTION

• Multicellular organisms, like unicellular
  organisms, need protection.
• This protection or defense is the combined effort
  of many systems.
• Cells work together as a tissue, organs work
  together in a system, and the systems work
  together to protect the organism.

CONTENTS
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PROTECTION
Skeletal System

• Your bones and cartilage protect organs.
• Your bones make up an endoskeleton (inside).
• Many animals have an exoskeleton (outside).

The horseshoe crabs shell is an exoskeleton.
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PROTECTION
Muscular System

• Your muscles aid in protection in allowing you to
  escape.

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PROTECTION
Nervous System
Endocrine System

• These 2 systems allow you to sense, react and
  escape danger.

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PROTECTION
Integumentary System

• Organisms have skin and often other protective
  coverings.

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PROTECTION
Circulatory System

• The circulatory system transports the food and
  oxygen that you need for dealing with
  emergencies.
• Your bloods ability to clot is protection from
  both blood loss and harmful pathogens.

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PROTECTION
Immune System

• But the Immune System allows your body to fight
  off pathogens (outside invaders) that actually
  enter your body.

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PROTECTION
Immune System

• An army of different types of white blood cells
  destroy these foreign pathogens and give you
  immunity (protection) from future invasions.

CONTENTS
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PLANT PROTECTION

• What are some of the organs that plants have to
  protect themselves?

Odor Skunk Cabbage
What else can you think of?
CONTENTS
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Reproduction

• All life can reproduce because every cell has
  DNA.
• Most multicellular organisms reproduce sexually
  by combining an egg with either a sperm or
  pollen.
• These two half cells have 1/2 the DNA of each
  parent and combine to form a whole cell.

Reproductive System
CONTENTS
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Plant Reproduction

• Plants, like animals, reproduce sexually. Flowers
  produce pollen which fertilize eggs to create
  seeds.
• Either wind or insects carry the pollen to
  another flower.

Reproductive System
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Reproduction

• But some multicellular organisms can reproduce
  asexually.
• Fungi produce spores which unlike eggs, sperm,
  and pollen contain a complete set of DNA. Only
  one parent is needed.

Reproductive System
CONTENTS