Studying Life

Characteristics of Living Things Does a Fire give off energy? Does a Fire fly (lightning bug) give off energy? Are they both Alive? What makes something alive?

Characteristic’s continued… Living things share several characteristics. These characteristics include the following: (There are 8 Characteristics!)

1. Living things are made up of Cells A cell is a collection of living matter enclosed by a barrier that separates the cell from its surroundings. A single cell is called “unicellular”. Many cells would be named “multicellular”

2. Living Things Reproduce All organisms produce new organisms. Asexually —single parent. Dividing in half to produce another organism. Sexually —two cells from different parents unite to produce the first cell of the new organism.

3. Living Things are based on a Universal Genetic Code Offspring always resemble their parents. With sexual reproduction, offspring differ in some ways. However, dogs must produce dogs, cats must produce cats and flies produce flies. The genetic code of each is what is produced.

4. Living things Grow and Develop Life Cycles Life cycle of a butterfly—egg—caterpillar—pupa (chrysalis)—adult butterfly Life cycle of a fly—egg—maggot—adult fly All living organisms grow at least part of their lives.

5. Living things obtain and use materials and energy As organisms grow, they need energy and materials to survive. What is an example of materials? Metabolism —The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes.

6. Living things respond to their Environment Organisms live in constantly changing environments. Examples: Temperature, Light, Smells, Sounds

7. Living things maintain a stable internal environment Changes that happen in organisms are complex. Example: a plant may take on water through roots at one point but give water off at another through leaves (transpire). The internal consistency is called Homeostasis. (process in which organisms keep their internal conditions stable)

Examples of Homeostasis: 1. Plants transpire: give off water 2. Humans perspire/sweat to cool off 3. The hormone insulin is used by the body to keep blood sugar level 4. Dogs pant to cool off

8. Living things change over time. Key words—as a group, living things evolve, or change over time. Example: Plants that can survive periods without water. These plants had to “change over time” to survive without water at certain dry periods.

Characteristics of Life Fire is NOT alive Bacteria IS alive Rocks are NOT alive Fungus IS alive Viruses are NOT alive

Viruses Viruses are NOT considered alive because they can not reproduce on their own. They must use cells from other organisms to reproduce

Branches of Biology The order in which Biology is branched, starting from smallest to most broad would be: Molecules (Smallest) Cells Groups of cells Organism Population Community Ecosystem Biosphere (Most Broad/Largest)

Levels of Organization (Largest) 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

Levels of Organization Individual living thing Organism 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 (Smallest)

The End