Is It Alive? The Seven Characteristics of Life

What is Biology?

• Biology –

What is Biology?

• Biology – the study of LIFE

What Makes Something Alive?

What Makes Something Alive?

• Biologists have established that all living things share seven characteristics in common.

• In order to be considereda “living” organism, one must show all seven characteristics.

1) Organization and Cells

• Organization – the high degree of order, both externally and internally, shown by living organisms.

• External Organization:

vs.

1) Organization and Cells

• External Organization:Externally, all wolves look essentially the same,

while rocks can come in many different shapes.

vs.

1) Organization and Cells

• Internal Organization:Internally, wolves (like other mammals) have

organs which are organized to work together to promote the well being of the organism.

vs.

1) Organization and Cells

• Cell – the smallest unit that can perform all of life’s process.

1) Organization and Cells• Cell – the smallest unit that can perform

all of life’s process.

• All living things are composed of, at least, one cell.

1) Organization and Cells• Cell – the smallest unit that can perform

all of life’s process.

• All living things are composed of, at least, one cell.

Unicellular – an organism made up of one cell

1) Organization and Cells• Cell – the smallest unit that can perform

all of life’s process.

• All living things are composed of, at least, one cell.

Unicellular – an organism made up of one cell

Multicellular – an organism made up of multiple cells

1) Organization and Cells

• A group of cells form a tissue,

• A group of tissues form an organ.

• A group of organs form an organism.

2) Response to Stimuli

• Stimulus – a physical or chemical change in an organism’s environment.

• How do you respond to stimuli?

2) Response to Stimuli

• Stimulus – a physical or chemical change in an organism’s environment.

• What happens when you shine a flashlight into your eye?

3) Homeostasis

• Homeostasis – the maintenance of stable internal conditions in response to environment.

3) Homeostasis

• Homeostasis – the maintenance of stable internal conditions in response to environment.

• Homeostasis occurs to combat ever-changing external conditions.

3) Homeostasis

• Homeostasis – the maintenance of stable internal conditions in response to environment.

• Homeostasis occurs to combat ever-changing external conditions.

Ex: SweatingHow does sweating maintain internal conditions?

4) Metabolism• Living organisms use energy to power all

their life processes.

• Metabolism – all chemical reactions occurring to take in and transform energy within an organism.

Plants get energy from _____ Animals get energy from ___

4) Metabolism• Living organisms use energy to power all

their life processes.

• Metabolism – all chemical reactions occurring to take in and transform energy within an organism.

Plants get energy from the sun Animals get energy from eating

5) Growth and Development

• Growth – an increase in size due to the division and enlargement of cells.

• Development – the process by which a young organism becomes a mature adult (capable of reproduction).

6) Reproduction• Reproduction – the process of creating

offspring.

• In order for a species to continue to exist, it must reproduce.

Sexual Reproduction requires both a male and female parent.

Asexual Reproduction requires only one parent.

7) Change Through Time

• Over long periods of time, populations of living organisms evolve new characteristics through the process of natural selection.

• This is the hardest characteristics to observe. Why?

Is It Alive? - Activity

• Form groups of 3 or 4 and choose one of the seven lab stations.

• On your own paper, each person within the group will – Identify the object– Determine if it is “alive” or “non-living”– Write two supporting sentences backing up

your claim with evidence from the lecture.

Exit Slip - This organism was recently discovered

on Mars. Scientists have asked you to determine if this is a living cell or a non-living object.

1)If this organism is alive, which two characteristics should it display?a) Response to Stimulus and Movementb) Breathing Oxygen and Change Over Timec) Reproduction and Homeostasisd) Growth and Producing Carbon Dioxide

Exit Slip - This organism was recently discovered

on Mars. Scientists have asked you to determine if this is a living cell or a non-living object.

2) When placed in cold water, this organism closes its pores to maintain heat. This is an example of what characteristic of living things?a) Metabolism b) Homeostasis c) Growth and Development d) Cells and Organization

Exit Slip - This organism was recently discovered

on Mars. Scientists have asked you to determine if this is a living cell or a non-living object.

3) Which statement would prove that this organism is NOT alive?a) this organism shows a high degree of internal organizationb) this organism derives energy from sunlight through photosynthesisc) this organism reproduces asexuallyd) this organism does not respond to stimuli