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!

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

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

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.

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

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

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.

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

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

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

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

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

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.

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

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)

Transport Movement of materials around inside the organism

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

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

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

Ecosystem - biotic and abiotic factors interacting

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

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

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

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 Go to Section:

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 Go to Section: