body plans and development cognitive learning systems, inc © 2008

Body Plans and Development

Cognitive Learning Systems, Inc © 2008

Body Plans and DevelopmentBody Organization


Animals


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Hierarchical OrganizationAnimals are organisms that have developed a system of organizing cells in order to best accomplish functions necessary to sustain life.


In most animals, cells are organized into larger structures called tissues.

Tissues are organized into organs.

Organs are organized into systems.

Systems work together for overall function of animal (organism).

cell

tissue

organ

system

organism

Tissues and Tissue Types


Tissue: a group of cells that have a common structure and function.

There are four main types of tissues in most animals:

Epithelial Connective

NervousMuscle

Epithelial TissueLocation

The covering of body surfaces: skin, scales, nails, feathers, claws

Lining of body cavities and organs: lining of stomach, lungs, kidney, blood vessels


Functions

Protection

Secrete and absorb substances, form glands

Examples

Epithelial tissue in skin protects internal organs from injury, helps prevent microorganisms from entering body, helps prevent loss of fluid from inside the body.

Epithelial cells of stomach secrete mucus that lubricates the organs and helps movement of food. Epithelial cells in the lungs allow for easy diffusion of gas.

Epithelial Tissue and Animals


Mammals: Epithelial cells secrete a substance called keratin which helps waterproof the skin.

Invertebrates: Epithelial cells secrete substances that help maintain the shelf or form of the body.

Fish: Epithelial cells secrete mucus which helps to reduce friction and drag force on fish.

Reptiles: Epithelial cells form scales.

Birds: Epithelial cells form feathers.

Connective Tissue


Connective tissue is defined as cells scattered through extracellular matrix. The extracellular matrix is a web of fibers that can be a liquid, jelly, or solid. Fibers are usually secreted by the cells of the connective tissue.

Location

Bones, joints (cartilage), fat, surface of blood vessels

Functions

Movement

Strength

Protection and Insulation

Examples

Connective tissue between the skin and underlying tissue allows the skin to move over bones and muscle. Tendons and ligaments allow bones and muscles to move without the skeleton falling apart.

Bones can absorb the impact in most cases without breaking.

Fat protects internal organs from impact and insulates body against cold temperatures.

Connective Tissue and Animals


Vertebrates (humans, reptiles, birds, fish): All contain similar types of connective tissue: adipose, bone, cartilage, tendons, ligaments.

Sharks and Rays: Cartilage forms the adult skeleton.

Sponges: The skeleton is different from what is technically considered connective tissue. It is made up of calcium carbonate structures, but no cells.

Nervous Tissue


Location

Brain, spinal cord, all body organs

Functions

Sensory Input

Motor Output

Interpretation and Cognition

Examples

Impulses traveling from a sense to the brain bring information about the external environment (senses of sight, hearing, smell, taste, touch). Impulses from internal organs provide information about the internal environment.

Impulses from the brain or spinal cord result in movement of muscles (biceps, heart, muscles in blood vessels) and secretion from glands.

Impulses within the brain allow for memory, comprehension, emotion, analysis of actions, interpretation of senses, and planning of movement.

The tissue that permits the communication between different areas of the body.

Nervous Tissue and Animals


Vertebrates (humans, reptiles, birds, fish): Nervous tissue tends to be organized to form a spinal cord, brain and sense organs.

Sponges: Arrangement of nervous tissue forms a nerve net. All of of the nerves are connected together to form a net-like structure.

Starfish: Arrangement of nervous tissue does NOT include a brain or spinal cord. Nervous tissue forms a neural ring in the center in the middle of the starfish and a radial nerve that extends into each leg.

Muscle Tissue


Muscle tissue is composed of long cells called muscle fibers which can contract when stimulated by a nerve impulse. There are three types of muscle tissue: skeletal muscle, cardiac muscle and smooth muscle.

Location

On surface of bones, in heart, in blood vessels and organs

Functions

Voluntary movement of body

Contraction of heart

Involuntary movement of body organs

Examples

Skeletal muscles are attached to bones by tendons. Contraction and relaxation of muscles moves bones of the body.

The wall of the heart is composed of cardiac muscle. Contraction and relaxation of cardiac muscle produces the contraction and relaxation of the chamber of the heart. It produces the heart beat.

Contraction and relaxation of smooth muscle in arteries changes the diameter of arteries. Changes in diameter change the rate at which blood flows through the arteries.

Muscle Tissue and Animals


Mammals: All possess three types of muscle tissue: skeletal, smooth and cardiac.

Sea anemones: These animals have single muscle cells rather than muscle tissue.

Arthropods: Skeletal muscles are not connected to as many nerves as in mammals.

Organs


Organ: a group of tissues that work together to perform a specific set of functions for the organism

Examples: Heart, Stomach, Skin, Lungs, kidney

As with tissues the structure and function of organs are related.

Organ Structure Function

Lungs Large single layer of cells next to capillaries that are only one cell thick.

Multiple lobes

Obtain oxygen from air and exchange it with carbon dioxide from blood

Small intestine

Long tube with many folds Move food from stomach to large intestine, chemically digest food to nutrients, absorb nutrients.

hair shaft

adipose cells (connective tissue)

connective tissue

Epithelial cells

sebaceous gland

4X objective

Skin• Function: Protection from external environment• Tissues: Connective, epithelial, nerve, and muscle

piloerector muscle

nerve


SystemsSystem: collection of organs or body structures that carry out a function necessary for survival of the organism.


Circulatory System

Function: To transport blood which contains gases, nutrients, waste and hormones around the body

Organs and structures: heart, veins, arteries, capillaries

Digestive System

Function: To break down and absorb nutrients

Organs and structures: mouth, esophagus, stomach, liver, small intestine, large intestine, pancreas

SystemsSystem: collection of organs and body structures that carry out a function necessary for survival of the organism.


Respiratory System

Function: To exchange oxygen and carbon dioxide between the blood and air outside the body

Organs and structures: mouth, nose, trachea, lungs

Nervous System

Function: To relay electrical signals through the body

Organs and structures: brain, spinal cord, nerves, sense organs

SystemsSystem: collection of organs and body structures that carry out a function necessary for survival of the organism.


Muscular System

Function: To provide movement to body limbs and organs

Organs and structures: skeletal muscles, smooth muscles, cardiac muscle

Skeletal System

Function: To provide support for the body and attachment for muscles and organs and to protect organs.

Organs and structures: bones, cartilage, tendons, ligaments

OrganismSystems group together to accomplish all of the major functions of an organism. Survival is dependent on all systems working together.


Example:

Nutrients are absorbed by the digestive system.

Absorbed nutrients are carried to parts of the body by the circulatory system.

In order for the heart to pump blood which will deliver nutrients, it needs oxygen and nutrients.

Oxygen is obtained by respiratory system and delivered to all parts of the body by the circulatory system.

PopulationBeyond the level of organism is that of a population.

A population is a group of individuals that rely and interact with each other.


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Check Understanding

1. How would you describe the hierarchial organization of the body?

2. How are the four different tissue types similar? How are they different?


Body Plans and DevelopmentMorphogenesis


What Can You Recall?


1. If an organ within a system is damaged, what effect would that have on the system? On other systems of the body?

2. Describe one function of each of the four types of tissue?


Development of Body OrganizationHow does body organization arise?

Is the body always organized the same?

Most animals have a life cycle that includes the following

fertilizationcleavageorganogenesispre-adultadulthoodsenescence

Morphogenesis is a term that can be used to describe the change in body organization through these stages.

Morphogenesis


Fertilization: fusion of genetic material from the gametes: sperm and egg. Embryo is a single cell at this stage.

Cleavage: Embryo divides by mitosis. Embryo becomes a small mass of cells at this stage.

Organogenesis: Cells in the embryo form layers. Cells within the layers then rearrange themselves to produce tissues and organs.

egg

spermembryo


Morphogenesis

Pre-adult stage:Organisms are not mature and cannot reproduce. In many species, preadult stage used for feeding and dispersal and is the longest stage.

FertilizationCleavage

Organogen

esis

egg

spermembryo


Morphogenesis

Adult stage: Organisms are mature, produce gametes and can reproduce. In many species this stage is very brief and only used for reproduction.

Senescence: Organisms age and die.

Fertilization Cleavage

Organogen

esis

Pre-adult stage

egg

spermembryo


Morphogenesis in insectsEmbryo formation, cleavage, and organogenesis all occur in a similar method to that shown with the frog.

AmetabolousPre-adult is similar to the adult. The adult is simply larger. Pre-adults go through different molting stages as they shed their exoskeletons.

HemimetabolousPre-adult stage is similar to adult. Pre-adult go through different molting stages as they shed their exoskeletons. During process some structural changes occur such as maturation of wings.

HolometabolousPre-adult go through different molting stages as they shed their exoskeletons. When pre-adult fully grown, molt to pupa stage in undergo complete structural changes.

egg

pre-adult

adult

pre-adult

adult

pre-adult

pre-adult

egg

pre-adult

pre-adult

adult

egg


Morphogenesis in humansHumans go through embryo formation, cleavage, and organogenesis. However, following organogenesis, there is a live birth rather than the laying of eggs.

Humans have one of the longest life-spans of animals. Human development following birth can be broken into the following stages: infancy, childhood, adolescence, adulthood.

Stages

Infancy (0-2 yrs)

Childhood (2-puberty)

Adolescence (puberty- 20ys)

Adulthood (after 20 years)

Changes

Rapid growth, teeth appear, brain enlarges

Rapid growth, shed primary teeth, obtain permanent teeth, increased muscle coordination

Change in muscle mass, rapid bone growth, change in hair distribution

Check Understanding

1. Most animals share the same stages of a life cycle. What are these stages?

2. In terms of survival and evolution, what is the importance of reaching the adult stage of a life cycle.


Body Plans and DevelopmentDifferentiation and Body Plans


What Can You Recall?


1. What occurs during the organogenesis stage of a life cycle?

2. Do all animals have the same pre-adult stage of a life cycle? Give an example to support your answer.

3. All animals die. Why are the stages of an animal’s life referred to a life CYCLE?


Unicellular vs Multicellular

One of the simplest ways to classify the body plans of organisms is to use the category of unicellular and multicellular organization.

Unicellular organisms are those that consist of a single cell.

Multicellular organisms are those that consist of more than one cell.

Fossils of bacteria from 3.8 billion years ago show that unicellular organisms inhabited the Earth BEFORE multicellular organisms.


Unicellular OrganismsALL prokaryotic and some eukaryotic organisms are unicellular. The difference between the two is that unicellular eukaryotes have a nucleus and nuclear membrane. Prokaryotes lack the nucleus and nuclear membrane.

Unicellular organisms can synthesize all of the substances they need from a few simple nutrients.

Each cell accomplishes ALL of the necessary functions necessary for that organism’s survival.

Unicellular organisms tend to reproduce quickly and the single cell can be used for reproduction.

Some unicellular organisms can be found in groups called colonies.

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Unicellular Organisms

Over evolutionary history, unicellular organisms have been successful in adapting to a variety of environments.

Unicellular organisms comprise more than half of the total biomass on Earth.

Examples of unicellular organisms: bacteria, yeast, algae, protozoa

Colony of algae protozoa

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Unicellular vs Multicellular

Multicellular organisms evolved after unicellular organisms.

The rise to a multicellular body enabled different cells to perform different functions of the organism.

Over the course of evolution this allowed for increasing specialization of body tissues and systems. In addition, multicellularity allowed for organisms to become larger because individual cells, tissues and organs could performed specialized functions.

In contrast to unicellular organisms, reproduction in many multicellular organisms occurs over a longer period of time and only specialized cells can be used for reproduction.

Examples of multicelllular organisms: fungi, plants, animals


Body Plans in Multicellular Organisms

Morphogenesis results in a different arrangement of tissues and organs in different multicellular animals. Differences in the arrangement of tissues and organs can result in different body plans.

One of the differences in body plans relates to the symmetry of the organism.

Symmetry refers to how the body of an organism could be divided so that it contained “equal” divisions.


SymmetryAsymmetrical body plan

Structure: No plane can divide the organisms into equal divisions

Examples: sponges

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SymmetryRadial symmetrical body plan

Structure: multiple planes of symmetry and body parts are organized around a central axis

Examples: coral, jellyfish, starfish

Radially symmetry allows for organisms to “reach out” in many directions from a central point. This is key as many radially symmetrical organisms tend to be less mobile in adult stage. This allows for increased ability to obtain food as it moves by the organism. It also allows for defense in many directions.

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SymmetryBilateral symmetrical body plan

Structure: a single plane of symmetry which produce mirror halves. Most sense organs located in the “front” of the animal.

Examples: humans, worms, arthropods

Bilateral symmetry allows compartmentalize of sense organs in a central place and the specialization of different areas of the body.

Different organs can be located in different parts of the body.

Bilateral symmetry also tends to allow animals to move faster and have more streamlined movement.

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Cephalization

In addition to symmetry the body plan of a multicellular organism can be differentiated by cephalization

Cephalization is the centralization of nervous and sensory tissues in the “head” of an animal.

Cephalization is associated primarily with bilaterally symmetrical animals, but can also be present in some radially symmetrical animals.


Cephalization

Cephalization allows a specialization of the body so that one end is responsible for encountering food, predators and other features of the external environment. Most bilateral animals have sense organs centralized in the head. This promotes ability to sense, coordinate and respond better to external environment.

Examples of animals with cephalization: Insects, crabs, birds, fish, mammals, hydra, flatworms

Hydramouth, photoreceptors and nerve cells are located at one end “head”

Flatwormssense organs and a brain located at one end

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Body Plan LandmarksAs scientists investigate and compare the bodies of animals, it is helpful to have terms that they can use to refer to different sections of the body.

The diagrams below show some of these terms and how they relate to the overall structure of some animals.

Dorsal (posterior): back side of the body, usually includes the brain and spinal cord

The spinal cord is dorsal (posterior) to the chest.

Ventral (anterior): front side of the body

The ribs are ventral (anterior) to the heart.

DorsalVentral




Lateral: farther from the midline of the body.

The arms are lateral to the heart.

Medial: nearer to the midline of the body.

The nose is on the medial side of the face.

laterallateral

medialmedial




Superior: toward the head or the upper part of a structure.

The heart is superior to the stomach.

Inferior: away from the head or toward the lower part of a structure.

The stomach is inferior to the lungs.

superior

inferior

Check Understanding

1. Locate the ventral side of the body.

2. Locate the dorsal side of the body.

3. Find a part of the body that is inferior to the chest.

4. Place your hands palms down. Locate the medial side of the hand.

5. Find a part of the body that is superior to the neck.

6. Stand. Locate the lateral side of the leg.


Body Plans and DevelopmentMaking and Applying Connections


Making and Applying Connections1. The table below shows the stages of the life cycles of different animals and the

type of birth of the animals. Which of the following conclusions can you make?

A. Reptiles, amphibians and mammals have completely different stage of their life cycle.

B. Only reptiles go through a stage of fertilization.

C. Reptiles, amphibians and mammals all hatch from eggs.

D. Only mammals go through live birth.

Animal Stages of Life Cycle before

birth

Stages of Life cycle after birth

Type of birth

Reptiles FertilizationCleavageOrganogenesis

Pre-adultAdult

Hatch from eggs

Amphibians FertilizationCleavageOrganogenesis

Pre-adultAdult

Hatch from eggs

Mammals FertilizationCleavageOrganogenesis

Pre-adultAdult

Live birth. Do not hatch from eggs


Making and Applying Connections

2. Peter noticed that some types of connective tissue are not found in all animals. He plans to research the type of connective tissue in the body of animals, and whether the animals have backbones or do not have backbones. Which of these questions is Peter most likely trying to answer?

A. Does the type of connective tissue differ between animals with

backbones and without backbones?

B. Does the type of backbone differ between animals?

C. Does the type of organs differ between animals with backbones and without backbones?

D. Does the type of connective tissue differ between animals with different body sizes?


3. Which of the following diagrams is correct about the stage of animal life cycles?



pre-adultadult

cleavage

organogenesisfertilization

A

cleavage

pre-adult

adult

organogenesisfertilization

B

pre-adult

adult

cleavage

organogenesis

fertilization

C

pre-adult

adult

cleavage

organogenesis

fertilization

D

Making and Applying Connections4. Which of the following animals has radial symmetry?


A B

C D

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5. The diagrams below show the life cycle of three different organism. What conclusions can you make about the organisms?

A. The pre-adults of the organisms all look the same.B. Only two of the organisms lay eggs.C. All organisms go through morphogenesisD. The adult stage comes before the pre-adult stage.


pre-adult

pre-adult

adult

egg

adult

pre-adult

pre-adult

egg egg

pre-adult

adult

pre-adult

Making and Applying Connections6. Madeline has been researching organisms from the Amazon jungle. She has

recorded information about each in the table below. What conclusions can she make about the organisms?

A. Organisms 1, 2 and 3 are multicellular organisms. B. Organisms 1 and 3 are most likely unicellular organisms. C. Organisms 2 and 3 are most likely multicellular organisms. D. Organisms 1, 2 and 3 are unicellular organisms.

Organism Observations Nucleus Cephalization

1 Can reproduce from a single cell

No No

2 Different cells perform specialized functions

Yes Yes

3 One cell performs all functions of the cell.

Yes No


Making and Applying Connections7. Which of these is NOT true about the relationship between cells, tissues

and organs?

A. Tissues are made up of organs. B. Tissues are made up of cells. C. Organs are made up of cells. D. Organs are made up of tissues.

8. Connective, muscle, nerve and epithelial are terms that describe which level of the organization of the body?

A. Systems B. Tissues C. Organs D. Population


Making and Applying Connections9. Which of these shows the dorsal side of the body?


dorsal

A

dorsal

B

dorsal

C

dorsal

D


10. Catherine is studying asymmetrical, radially symmetrical and bilaterally symmetrical animals. In which animals is she MOST likely to see cephalization?

A. Asymmetrical animals.

B. Radially symmetrical animals.

C. Bilaterally symmetrical animals.


body plans and development cognitive learning systems, inc © 2008

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