Chapter 2: The Nature of living Things

1.Organisms are made up of one or more cells

2.Organisms use energy

3.Organisms are adapted to their environment

4.Organisms respond to stimuli

5.Organisms produce more organisms of their own kind

6.Organisms grow and develop

CELLS Cells are the basic units of structure and function

in living things, often called the “building blocks” of life.

Organisms may be made up of one cell or many cells. One celled organisms are called UNICELLULAR.

MULTICELLULAR organisms are made up of two or more cells

ENERGY

Energy is the ability to do work.

The sun is the major source of energy for most living things.

Plants and some bacteria use the energy in sunlight to make food.

Animals benefit from the energy in the sunlight by eating plants or other animals.

Why is it necessary to have plants in order for animals to survive?

ADAPTATION

It is any characteristic of an organism that helps the organism survive, or live successfully in its environment.

Adaptations make it possible for one kind of organism to survive in an environment where other kinds cannot.

List different organisms that have adapted to their environment and could not adapt to another.

RESPONSE and MOVEMENT

A response is a reaction to a change in the environment. Examples??

A change in the environment that causes a response is a STIMULI.

All living things respond to stimuli. For example: when an earthworm is exposed to bright light, the earthworm burrows quickly. When you touch something hot, you quickly remove your hand. What are the stimuli and responses in these two examples?

The response of a plant to a stimulus is called a TROPISM. For example: Farmers do not have to worry about which way to place seeds in the ground. Why not?

Because gravity causes the root to grow downward. The downward growth is an example of a tropism. Many flowers open during the day and close at night. What stimulus do you thick causes this response?

Only certain parts of the plants move. When an organism moves its entire body from place to place, the movement is called LOCOMOTION.

REPRODUCTION

Reproduction is the process by which organisms produce offspring.

Reproduction is not necessary for the survival of an organism.

If organisms do not reproduce, however, their species will become extinct.

Until the seventeenth century, many people believed that living things came from none living matter.

For example, people thought frogs formed from mud, and flies came from spoiled meat. The theory stating that organisms could come from nonliving matter is called SPONTANEOUS GENERATION.

How could you provide evidence that flies do not come from spoiled meat, or that frogs do not form from mud?

ASEXUAL REPRODUCTION

Asexual reproduction requires only one parent organism.

Offspring are produced when the parent organism splits in two. This process is called FISSION.

Another form of asexual reproduction is budding. Budding is the growth of a new organism from the parent organism.

In asexual reproduction, a new organism is an exact copy of its parent.

SEXUAL REPRODUCTION

In sexual reproduction, cells from two parents join to form a new organism.

Offspring that result from sexual reproduction are not identical to either parent organism.

Instead, the offspring have some characteristics of each parent.

GROWTH and DEVELOPMENT

An organism changes in many ways during its lifetime. All the changes that take place in an organism over its lifespan are called development.

One way organisms change is by growing, or becoming larger. Unicellular organisms, growth occurs as new material is added to the cell

The cells of a multicellular organism also grow as new material is added to the cell. But most growth is caused by the formation of new cells.

LIFE SPAN

Life span is the period of time in which an organism lives.

Every organism has a life span, though each one will vary.

LIFE CYCLE

The life cycle of an organism is all the changes that the organism goes through during its life span.

Life Processes of OrganismsThe life processes are all of the things a living thing must do

to stay alive.

Nutrition, respiration, excretion, and transport are four life processes of organisms.

1. NUTRITION: All organisms need food. Using sunlight and materials from the environment, green plants can make their own food. Animals, however, cannot make their own food, they depend on plants and other animals for their food supply.

The process of taking food into the body from the outside is called INGESTION.

Why do we need food?

Food provides an organism with the NUTRIENTS, or materials needed for growth, energy, and the life processes.

Before an organism can use the nutrients in food, the food must be broken down through a process known as DIGESTION. Digestion breaks down the food into usable forms for the systems in the body.

The complete process of ingestion and digestion is called nutrition. Proper nutrition provides an organism with energy. It also provides an organism the materials needed for growth and development.

PHOTOSYNTHESIS Using water, carbon dioxide, and sunlight, plants

are able to make their own food. Plants are called producers because they make or produce their own food through a process known as PHOTOSYNTHESIS.

Photosynthesis usually takes place in the leaves of green plants. The food produced is a simple sugar called glucose. Some of the food made during this process is used for growth and development. The rest is stored away. By eating plants, animals obtain energy.

Chemosynthesis: Some organisms use chemicals instead of sunlight to make their food. Deep sea bacteria use chemicals such as hydrogen sulfide and ammonia to make food.

RespirationOrganisms obtain food energy from food by

carrying on respiration.

Respiration occurs when oxygen is involved in the process of breaking apart food in the cells. The breakdown releases energy.

It also produces carbon dioxide and water.

The carbon dioxide and water are waste products.

The products of digestion that are not used by organisms are also waste products.

The removal of waste products from the cells of an organism is called EXCRETION.

Organisms must remove waste products from their cells to remain healthy.

TRANSPORT Nutrients taken in by one part of an organism

usually are needed by other parts of that organism.

All organisms take in nutrients from the environment.

Organisms also release waste products.

The life process of moving nutrients throughout an organism and removing waste products is called TRANSPORT.

Needs of Organisms

Organisms get all of the things they need from the environment.

Organisms need water, nutrients, air, a proper temperature, and a living space.

Water makes up about three quarters of most living things. The life processes of living things depend on water.

Most organisms need air to survive. Plants use carbon dioxide in the air to make food and release oxygen as a waste product. In respiration, animals take in oxygen and release carbon dioxide.

Organisms also need a proper temperature to carry out their life processes. When the temperature decreases, the life processes of most organisms slow down. Many organisms are not active in cold weather.

HOMEOSTASIS is the ability of an organism to keep conditions inside its body constant. It allows an organism to keep warm during the winter and cool in the summer.

All organisms need living space. Living space provides plants with enough air, sunlight, water, and nutrients for photosynthesis. Animals need living space for air, food, water, shelter, and reproduction.

The living space in the environment is limited. As a result, organisms must compete with each other for living space. The struggle between organisms for the available space in the environment is called COMPETITION.