chapter 4: section i: pages 124 - 129 what is life?

Chapter 4:Section I: Pages 124 - 129

What is Life?

The Characteristics of Living Things

6 Characteristics:1. Made of Cells

2. Contain Similar chemicals

3. Use energy

4. Grow and develop

5. Respond to their Environment

6. Reproduce

Cellular Organization

• Cell – basic unit of structure and function– building blocks of life

• Think Legos = individual just a block, together you can create anything.

Cellular Organization

• Structure– How the cells come together to create

something• Think Blueprint for building a house.

Cellular Organization

• Function– The job or task that something does.

• Think, a hand’s function is to grab or hold things.

Cellular Organisms

• Unicellular– 1 cell (Very Small)– Example: bacteria and ameba

• Multicellular– 2 or more cells (Varies in size)– Example: people, muscles, nerves

The chemicals of life

• Carbohydrates– The cells main source of energy.

• Proteins and Lipids– The cells building materials

• Think wood and bricks of a house.

Energy Use

• Use energy to grow and repair injured parts.– Examples:

• Cells in stomach and intestines are used to digest food.

• Blood cells move chemicals throughout the body.

Growth and Development

• Growth = the process of becoming larger.

• Development = the process of change that occurs during and organisms life to produce a more complex organism.

• Think – acorn – seedling - tree

Response to Surroundings

• Stimulus (plural stimuli)– A change that causes an organism to react.

• External Stimuli – comes from outside the organism

– Example: light, sound, and temperature of the environment

• Internal stimuli – comes from within the organism– Example: hunger and thirst

Response to Surroundings

• Response– How an organism reacts to a stimuli– Is a change in action or behavior

• Example: Stimulus = Friend jumps out and scares youReaction = You jump and scream

– Non-living things do not react to stimuli.

Reproduction

• Reproduce – produce offspring that are similar to the parents.– Example:

Robins lay eggs, that develop into young robins that look like their parents.

Life Comes From Life

• Spontaneous Generation:– Idea that living things can arise (come from)

nonliving sources• Example:

flies from rotting meatfrogs from mud puddles

Dr. Francesco Redi

Dr. Louis Pasteur

The Needs of Living Things

Living things must satisfy their basic needs.1. Energy (food)

2. Water

3. Living Space

4. Stable Internal Conditions

1: Energy

• Autotrophs: makes own food– Auto = self troph = feeder

• Example: plants

– Solar Energy is directly related to food production.

1: Energy

• Heterotrophs: cannot make own food– Hetero = others troph = feeder

• Examples: animals, mushrooms, slime molds

– Solar Energy is an indirect source of energy.• Plants need the energy to survive, heterotrophs

need the plants to survive.

2: Water

• ALL living things need water to survive.

• Most organisms can only live a couple of days without water.

2: Water

• Used for:– Obtaining chemicals from surroundings– Breaking down food– Growing– Moving substances within organism– Reproduction

• Fact: 92% of the liquid part of your blood is water.

3: Living Space

• Every organism needs a place to live. (Shelter)

• Limited resources cause competition.

• Plants are stationary and do not move locations to compete.

• Animals move around.

4: Stable internal Conditions

• Homeostasis: Stable inside despite changes in the surroundings

• Example: – Your body temperature stays at 98.6 degrees while the

temperature outside is less than that.– A barnacle's ability to store water to maintain life outside

the ocean water while in low tide.