1. Homeostasis must be maintained inside the cell if it is to survive!
Living Environment Ch1.3
Characteristics of Living Things
ALL Living things are made up of units called cells
- a cell is a collection of organelles surrounded by a barrier
Homeostasis must be maintained inside the cell if it is to survive!

2. What is
Homeostasis?
Maintain a stable environment inside a cell or an organism even when outside conditions are changing.

3. WHAT needs to be maintained?
Temperature
Materials needed for energy
Absence of waste materials pH
and on and on...
Nutrients + Oxygen
Energy + Carbon Dioxide

4. HOW are these properties maintained?
There are eight (8) life processes--GRRSNERT--that are performed in every cell and every organism.
These processes work together to maintain homeostasis.

5. Growth All living things grow. They increase in the size
and/or the number of cells
why?
Development from single cell to complex organism
Maintenance or repair of existing tissue

6. Living things grow and develop
- each organism has a distinctive life cycle
- some organisms go through metamorphosis

7. Respiration Two kinds:
ALL living things require energy. Releasing energy from nutrients is called cellular respiration.
Two kinds:
Aerobic - requires oxygen and provides much more bang for the buck
Anaerobic – No O2 needed but much less energy released from nutrients, and creates nasty by-products like lactic acid (ouch) or alcohol.

8. Reproduction Producing more of the same kind of organism Two kinds:
Asexual (bacteria and single-celled organisms)
Sexual (everybody else)

9. - offspring always resemble their parents
- directions for inheritance are carried by DNA
-The universal genetic code all Living things are based on

10. Synthesis
Combining simple substances chemically to form more complex substances.
Requires Energy (ATP)

11. Nutrition
Obtaining the necessary nutrients for energy and building blocks for synthesis
Three steps:
Ingestion
Digestion
Egestion
Organisms obtain nutrients
in 2 ways …

12. Autotrophs
- produced their own food
- they use sun energy to produce chemical
energy by the process of photosynthesis

13. they use preformed organic compounds, sugar
b. Heterotrophs
they use preformed organic compounds, sugar
They are organisms that cannot produce their own food. They must consume compounds formed by other organisms.

14. Excretion Like what? Removal of metabolic waste
Carbon Dioxide - produced by respiration
Urine - contains Urea, Salts, Water

15. Regulation How is this done in humans? Two systems share the job:
Keeps all the body systems working together (communication)
How is this done in humans?
Two systems share the job:
Nervous System (electrical messages)
Endocrine System - sends out hormones (chemical messages)

16. Transport
Movement of materials around inside the organism

17. Living things respond to their environment
Types of Environmental changes
temperature
moisture abiotic
amount of sunlight
minerals
introduction of new plants
introduction of new animals biotic
competition between organisms

18. mammoth mastodon 8. Living things change over time - Evolution
- in order for an organism to change, it's DNA must change
mammoth
mastodon

19. II. Levels of Organization of Living Things
Biosphere - the portion of the earth where life exists.

20. Ecosystem - biotic and abiotic factors interacting

21. Community - all populations living in a defined area.
Ex; deer,grass, snakes, hawks, mice

22. Population
– all the organisms of one type
living in a same area
Organism
- one individual living thing

23. Organ System - nervous system
Organ - brain
Tissue - nervous tissue

24. Levels of Organization
Biosphere
The part of Earth
that contains all
ecosystems
Biosphere
Community and
its nonliving
surroundings
Ecosystem
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
Populations that
live together in a
defined area
Community
Hawk, snake, bison, prairie dog, grass
Group of
organisms of one
type that live in
the same area
Population
Bison herd
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25. Organism Groups of Cells Cells Molecules Go to Section:
Individual living
thing
Bison
Groups of
Cells
Tissues, organs,
and organ systems
Nervous tissue
Brain
Nervous system
Smallest functional
unit of life
Cells
Nerve cell
Groups of atoms;
smallest unit of
most chemical
compounds
Molecules
Water
DNA
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