Characteristics of LifeCh. 1.1 – p.8-16

NEW SPECIES OF 2013

Vocabulary

Organism – things that have all the characteristics of life

Cell – the smallest unit of life Unicellular – living things that are made of only one cell Multicellular – organisms made of more than one cell Homeostasis – an organism’s ability to maintain steady

internal conditions when outside conditions change

Characteristics of Life

What makes something living?

Basic Functions of Life

All living things are… Organized Grow and develop Reproduce Respond Maintain certain internal conditions Use energy

*Are all of these necessary for life? Can you think something that fits some but not all of these

features?

Organization

Living things are organized with structures that have specific functions.

Does an organism made up of only one cell organized?

Unicellular Organisms

Unicellular organisms are organisms made up of only one cell.

Within the cell, different structures have specialized functions.

Multicellular organisms

Living things that are made of more than one cell we call multicellular.

Multicellular organisms can be made of two cells or trillions of cells. We are made up of around 37 trillion cells.

However, cells in multicellular organisms can differ depending on function. A heart cell is different from a brain cell is different from a

muscle cell is different from a skin cell is different from…

Growth and Development

All living things grow!!!

Unicellular organisms grow in size as they get older.

As multicellular organisms grow they increase their number of cells.

Development

Changes that occur in an organisms lifetime are called development.

Development happens as cells develop and specialize into different cell types.

Some developmental changes are dramatic…some are less dramatic

Reproduction

Reproduction is the process of one organism making one or more new organisms

Some organisms within a population might not reproduce….that’s ok, because hopefully others will. If no organisms in a population reproduce, that species

will no longer exist in that environment.

Some organisms of a species must reproduce for the species to survive.

Reproduction

Not all organisms reproduce the same way. Some reproduce by division.

Others have specialized cells for reproduction.

Some organisms must have a mate to reproduce.

In the end, the number of offspring a species has can also vary. Frogs can produce hundreds offspring. Humans only make one or

two.

Response to Stimuli

All organisms respond to changes in the environment

These changes can be internal or external and are called stimuli.

Internal Stimuli

External Stimuli

Responds to light and heat

Plants often turn towards light. This is called tropism.

Some animals respond to temperature changes.

What happens when you are cold?

What happens when you are hot?

Homeostasis

An organism’s ability to maintain steady internal conditions when outside conditions change.

Cells in certain conditions to function properly.

Maintaining homeostasis ensures that cell work.

If cells cannot function normally, an organism can become sick and even die.

Temperature classification

Core (rectal, esophageal, etc.)

Hypothermia <35.0 °C (95.0 °F)[2]

Normal 36.5–37.5 °C (97.7–99.5 °F)[3]

Fever >37.5–38.3 °C (99.5–100.9 °F)[4][5]

Hyperthermia >37.5–38.3 °C (99.5–100.9 °F)[4][5]

Hyperpyrexia >40.0–41.5 °C (104.0–106.7 °F)[6][7]

Note: The difference between fever and hyperthermia is the underlying mechanism.

Methods of Regulation

How does shivering help to regulate body temperature when too cold?

How does sweating help with too warm?

However, there are limits to the amount of change an organism can withstand.

For example, a human can only survive for 5 minutes in Arctic waters before dying due to hypothermia.

Unicellular homeostasis

Unicellular organisms maintain homeostasis in different ways.

Paramecium, a protist, has structures called contractile vacuoles that collect and pump out water excess water.

Similar to how we will have to go to the toilet more if we drink more water than normal.

Without contractile vacuoles, the paramecium may burst if it takes in too much water

Energy

Everything you do requires energy!

Even if you are doing nothing.

Cells continuously use energy to transport substances, make new cells, and perform chemical reactions.

Where does this energy come from?

Notebook Questions:

Are cells living?

Are the things inside cells alive?

What is homeostasis?

Name all 6 characteristics of a living thing?

Think, Think, Think: How does being able to respond to stimuli allow us to maintain homeostasis?