Honors Biology: Unit 1 Characteristics of Life

organ

group of tissues that work together to perform closely related functions

DNA

genetic information in a cell

Examples of homeostasis

blood pH/body temperature/ O2 levels/ hormones

Tissue

A group of similar cells that perform the same function

Stimulis

A change in an organism's surroundings that causes it to react

8 characteristics of life

1. Cellular organization (levels of organization)
2. Reproduction.
3. Metabolism.
4. Homeostasis.
5. Heredity.
6. Response to stimuli.
7. Growth and development (life cycle)
8. Evolution

organ system

group of organs that work together to perform a specific function

Metabolism

all chemical reactions in an organism that provide energy for cell processes.

Homeostasis

all living things have homeostasis. the ability to maintain a stable internal environment

Heredity

all living things have heredity. The ability to pass traits from parents to offspring through DNA.

Mutations

Random changes in the DNA of a species. The source of all genetic diversity. It leads to the evolution of a species.

Responding to their environment

how a living thing detects a change in their environment and reacts to stay alive. Involves a stimulus and a response.

Examples of responding to the environment

pupils dilating/restricting.

Response

An action or change in behavior that occurs as a result of a stimulus.

Evolution

all living things evolve. change in a kind of organism over time; the process by which modern organisms have descended from ancient organisms.

Unicellular

Organisms consisting of only a single cell

Multicellular

Organism containing hundreds to even trillions of cells

Eukaryotes

Organisms that have one or more cells and contain a nucleus and organelles. Humans are an example.

Levels of organization

cell/ tissue/organs/organ system/organism (smallest to largest)

Cell

Is the basic unit of life. All organisms are made of cell(s)

Organism

Is an individual living thing made up of one or many cells

Prokaryote

Unicellular organism without a nucleus. Bacteria are an example