CHAPTER 6 ORGANIZATION OF LIFE

CHAPTER 6

ORGANIZATION OF LIFE

The smallest unit of an organism is a cell. Cells group together and form tissues; tissues and

then form organs, organs will form organ systems; and finally organism.

Living organisms can consist of only one cell called unicellular organism (examples;

Amoeba, Paramecium, and Euglena). Plants and animals are living organism consisting of more

than one cell and called multicellular organism.

A. Cell

1. Elements of cell

The main elements of a cell are the plasma membrane, protoplasm, and the nucleus.

The plasma membrane is the outer part of a cell. It controls the traffic of any material

in and out of the cell.

Protoplasm is the living contents of a cell. It is controls all the activities within the

cell. Protoplasm is composed of water, protein, carbohydrates, fats, mineral salts, and

enzymes. Protoplasm located inside the nucleus is called nucleoplasm. Protoplasm located

outside the nucleus is called cytoplasm. Cell organelles are located in the cytoplasm.

Inside the nucleus, there are chromosomes containing genes, which basic function is

to carry hereditary materials across generations.

2. The differences between animal cells and plant cells.

The differences between animal cells and plant cells are in the plasma membrane,

cytoplasm, and vacuole.

The plasma membrane in a plant cell is protected by a strong and tick cell wall, so a

plant cell constant shape.

Cytoplasm in plant cell contain plastids, which are granules carrying color

substances (chloroplast), containing chlorophyll which is used in the photosynthesis

process.

The vacuole is clearly visible in plant cell. It is produced as the result of cell wall

development which is faster than the growth of protoplasm.

B. Tissues

Group of cells with similar shape and function are called tissues.

Animal tissues

The animal body is composed of various tissues, for example, bone tissue functions to form

skeletons which further strengthen the body.

Nervous tissue function to transmit stimulus. The red blood tissue are carry oxygen from

respiratory organs. The muscle tissue play the role to generate motion.

Plant tissues

A plant is also formed of groups

of cells which may have different

shape and functions.

Epidermis tissues are covers and

protects the surface of a plant.

Vascular tissues are composed of

xylem and phloem tissues.

Xylem tissues allow water and

minerals to be transported from

the root to the leaves.

Phloem tissues allows the

photosynthetic nutrient to be transported from the leaves to the rest of the plant.

Vascular tissues may be found in every part of the plant (roots, stems, and leaves).

Palisade and spongy tissues are the primary location of photosynthesis because they contain

chlorophyll, especially the palisade tissues.

C. Organs

These groups of tissues are called organs.

1. Human body organs

Several important organ in the human body are the

heart, lungs, liver, kidneys, and stomach.

The heart function is responsible to pump blood

throughout the body.

The heart is composed nervous tissues, muscle

tissues, and blood vessels.

The lungs are responsible for performing respiratory

function.

The liver is responsible for controlling the

composition of nutrients and toxins within the blood.

Kidney are responsible for performing excretion,

such as removing residual substances containing nitrogen.

The stomach is responsible for the digestive function.

2. Plant organs

Plant are composed of the leaf, stem, and root.

a. Leaf

Plant leave are composed of epidermis tissues,

palisade tissues, spongy tissues, and vascular

tissues (xylem, and phloem).

Leaves are the location of photosynthesis and

also are responsible for respiratory functions.

b. Stem

The stem is composed of epidermis, cortex, and

stele which consist of parenchyma and vascular tissues (xylem and phloem).

The stem is responsible for transporting water and minerals from the roots to leaves

through the xylems, and transportation of nutrients from the leaves throughout the

whole parts of the plant through the phloem.

c. Roots

Roots are composed of epidermis tissues, the cortex, endodermis, pericambium, and

stele. They work together in tandem to absorb water and minerals from the ground.

Roots are also responsible for respiratory function.

D. Organ Systems

Several organs will work together to form an organ system.

Example organ system in humans are the digestive and respiratory system.

The digestive system is composed of several organs, such as the mouth, throat, stomach, liver,

and gall bladder, pancreas, small intestines, colon, and anus.

The respiratory system consist of several organs, such as the nose, trachea, bronchi, and lungs.

Digestive system Respiratory system

The human body also possesses some other organ system, example; the circulatory system,

excretory system, skeletal system, and the

nervous system.

Group of several organ systems are connected to

each other and work together to form organism.

The body of living organism is considered as an

organization of life that are consecutively

composed of:

cells tissues organs organ

systems organism

Disorder of one of the organ systems may affect

the performance of other organ systems.

Example: Kidney disorders may affect blood

circulation.

The description about the organization of life

can be explained using beside figure

CHAPTER 2

ECOSYSTEM

A. Environment

An environment is the totally of circumstances surrounding of living organisms which affect

their lives.

The suitable area for living organisms to perform their living activities is called a habitat.

B. Unit of Living Organisms in an Ecosystem

An ecosystem consist of living organisms (biotic) and non-living object (abiotic). Living

organism in an ecosystem consist of units such as, individual, population, and community.

1. Individual

A single, separate organism in an environment is called an individual. A fish, a turtle, or

alga is called an individual.

2. Population

The population is a group of individuals within the same species living in a certain area.

The number of individuals within the same species living in a certain unit area is called

the population density.

Example:

An area of 10 km2 is occupied by 50 deers.

The density of the deer population = 2km 10

deers 50 =

2km

deers5

3. Community

A community is composed of all the populations living organism inhibiting the same area

and interacting with one another.

A population goldfish, a population of mujair fish, a population of water lilies, and

population of Hydrilla in a lake are members of aquatic lake

community.

C. Ecosystem

Ecosystem are groups of communities and environments which

interact with each other.

Based on the formation process, an ecosystem is distinguished into a

natural ecosystem and an artificial ecosystem.

A natural ecosystem is an ecosystem which is naturally formed, for example lakes, swamps,

seas, forests, prairies, and rivers. Natural ecosystem can be broken down into land

ecosystems, freshwater, seawater, and beach ecosystems.

An artificial ecosystem is an ecosystem made by humans, for example, reservoirs, rice fields,

ponds, and aquariums.

D. Component of Ecosystems

Ecosystems consist of two main components, they are abiotic, and biotic component.

1. Abiotic components

Abiotic is all non-living objects found in an ecosystem.

Examples of abiotic components are water, soil, rocks, sand, air, light, temperature,

humidity, and gravity.

2. Biotic components

Based on the roles in an ecosystem, biotic components may be classified into three

groups; producers, consumers, and decomposers.

a. Producers

Producers are a group of living organisms which are able to produce their own food

(nutrients).

Green plants are called producers since they are able to produce their own food or

nutrient.

b. Consumers

Consumers include all animals and humans.

Animals which directly eat plants are considered as first level consumer (primary

consumer).

Animals which eat a first level consumer are considered as a second level consumer

(secondary level).

Animals which eat a second level consumer are considered as a third level consumer

(tertiary level).

c. Decomposers

Bacteria and saprophytic fungi are responsible for decomposing dead and decaying

organisms.

The producers are needed by the first level consumers; the first level consumers are

needed by the second level consumers; the second level consumers are needed by the

third level consumers (tertiary consumers); and so on.

Dead organisms, either from producers or consumers, will be decomposed by

decomposers.

E. Interdependence between Biotic and Abiotic Components

There is an interdependence between biotic components (human beings, animals, and plants)

and abiotic components (environment) within an ecosystem. Biotic components rely on

abiotic components. Biotic components may also affect abiotic components.

There are some abiotic components which cannot be affected by biotic factors, example; earth

gravity, sunlight, and air pressure.

F. Interdependence Among Biotic Components

There is an interdependence among biotic components. This interdependence forms a

continuous cycle.

In an ecosystem there is interdependence among its biotic components, which are producers,

consumers, and decomposers.

1. Food chain

The series of eating phenomena will form a food chain.

2. Energy flow in the food chain.

If plants are eaten by first level consumers, the energy stored within the plants is

transferred into the first level consumers. Furthermore, if first level consumers have been

eaten by second level consumers, energy from first level consumers is transferred into the

bodies of second level consumers, and so on. This phenomena is called a transfer of

energy.

3. Food webs

Food webs is a group of several food chains which are interconnected to one another.

This food web show a series of eating and being eaten within an ecosystem.

4. Pyramid of food

A pyramid of food is a composition of food chains which the higher the level position the

lesser the quantity.

Organisms Interaction

Mutualism

Commensalism

Parasitism

Competition and Predation

CHAPTER 3

ENVIRONMENT POLLUTION

A. Air Pollution

A pollutant is a substance that contaminates the environment. Air pollutants include

soot, smoke, ash, and gases such as carbon dioxide (CO2), carbon monoxide (CO), nitrogen

oxides (NO), and sulfur oxides (SO).

Wherever cars, trucks, airplanes, factories, homes, or power plants are found, air pollution is

likely.

Air pollution can be caused by volcanic eruptions, wind-blown dust and sand, forest fires, and

the evaporation of paint and other chemical.

Smog is a form of air pollution created when sunlight reacts with pollutants produced by

burning fuels. It can irritate the eyes and make breathing difficult for people with asthma or

other lung diseases.

Smog can be reduce if people take buses or trains instead of driving or if they use

vehicles, such as electric cars, that produce fewer pollutants than gasoline-powered vehicles.

B. Water Pollution

Wastewater from factories and sewage-treatment plants often is released into

waterways. In the United States and many other countries, laws require that wastewater be

treated to remove pollutants before it is released. But, in many parts of world, wastewater

treatment is not always possible. Pollution also enters water when people dump litter or waste

materials into rivers, lakes, and oceans.

Some water pollutants poison fish and other wildlife, and can be harmful to people who

swim in or drink the water. For, example, chemical pesticides sprayed on farmland can wash

into lakes and streams. These chemicals can harm the insects that fish, turtles, or frogs rely on

for food. Shortages of food can lead to deaths among water-dwelling animals.

Some pollutants, especially those containing mercury and other metals, can build up in

the tissues of fish. Eating contaminated fish and shell-fish can transfer these metals to people,

birds, and other animals. In some areas, people are advised not to eat fish or shellfish taken

from polluted waterways.

Algae blooms are another water pollution problem. Raw sewage and excess fertilizer

contain large amounts of nitrogen. If they are washed into a lake or pond, they can cause the

rapid growth of algae. When the algae die, they are decomposed by huge numbers of bacteria

that use up much of the oxygen in the water. Fish and other organisms can die from a lack of

oxygen in the water.

Rivers and streams eventually flow into oceans, bringing their pollutants along. Also,

polluted water can enter the ocean in coastal areas where factories, sewage-treatment plants,

or shipping activities are located. Oil spills are a well-known ocean pollution problem. Much

of that oil comes from ships that use ocean water to wash out their full tanks.

C. Soil Pollution

Soil can become polluted when air pollutants drift to the ground or when water leaves

pollutants behind as it flows through the soil. Soil also can be polluted when people toss litter

on the ground or dispose of trash in landfills.

Most of solid waste is dumped in landfills, for example old refrigerator, old TVs, and

toys. Most landfills are designed to seal out air and water. This helps prevent pollutants from

seeping into surrounding soil, but it slows normal decay processes.

Even food scraps and

paper, which usually

break down quickly, can

last for decades in a

landfill. In populated

areas, landfills up

quickly. Reducing the

amount of trash people

generate can reduce the

need for new landfills.

Waste materials that are harmful to human health or poisonous to living organisms are

hazardous wastes. They include dangerous chemicals, such as pesticides, oil, and petroleum-

based solvents used in industry. They also include radioactive wastes from nuclear power

plants, from hospitals that use radioactive materials to treat disease, and from nuclear

weapons production.

Many household items also are considered hazardous. If these materials are dumped into

landfills, they could seep into the soil, surface water, or groundwater over time. Hazardous

wastes usually are handled separately from other types of trash. They are sealed in steel drums

or treated in other ways to prevent them from polluting the environment.

References:

Sumarwan, Sumartini, and Kusmayadi. 2011. Bilingual Science Biology for Junior High School

1. Jakarta: Erlangga.