The Study of Life

All Living Things Share Common Characteristics 1. Basic Unit is the Cell 2. They Reproduce 3. Grow & Develop 4. Respond To Their Environment 5. Maintain A Stable Internal Environment 6. Have Complex Chemistry

All Organisms are made of Cells

Facts About Cells Cells are the smallest living unit of an organism All cells contain living material called cytoplasm All cells are surrounded by a cell membrane that controls what enters & leaves the cell

More Cell Facts Cells are complex & highly organized Cells have parts called organelles that do different jobs e.g. Chloroplasts in plants make sugars

The simplest cells are called Prokaryotes a. These cells DO NOT have a nucleus or membrane-bound organelles b. Archaea and Bacteria are examples

More complex cells are called Eukaryotes a. These cells DO have a nucleus and membrane-bound organelles b. Eukarya (plants, animals, & fungi) are examples

Unicellular Organisms - Living Organism Made Up Of One Cell a. Examples: Archaea and Bacteria Multicellular Organisms - Living Organism Made Up Of Many, Specialized Cells b. Examples: Eukarya

Organisms Reproduce to Pass on their Genetic Traits

Two Types of Reproduction Sexual Reproduction Involves 2 parents Egg fertilized by sperm to make a ZYGOTE Offspring DIFFERENT from parents

Two Types of Reproduction Asexual Reproduction Involves a single organism or cell Cell divides Offspring IDENTICAL to parent

Organisms Grow & Develop

Growth & Development Cells grow by producing MORE CELLS & by cell ENLARGEMENT Organisms develop as they mature into an adult organism

Organisms Respond to Environment Organisms Respond to Temperature, Water, Food Supplies, etc. In Order To Survive & Reproduce

Homeostasis Keeping The Internal Environment Of The Cell or Organism Within The Ranges Required For Life Stable internal conditions of pH, temperature, water balance, etc.

Living things have complex chemistry Consist of large complex chemicals Undergo complex chemical reactions to carry out all functions for life

Unifying Themes of Biology Cell theory Gene theory Homeostasis Evolution

Cell Theory All living things are made of cells Living cells come from other living cells Living things can be unicellular (bacteria) or multicellular (plants, animals)

Gene Theory Characteristics of living things are controlled by genes Genes are passed on from parents to offspring

Homeostasis Maintaining a stable environment

Evolution Change in the characteristics of living things over time Evolution occurs through natural selection Organisms with more suitable adaptations for their environment are able to survive and reproduce

Life is Organized on Several Levels

Organizational Levels of Life A. Biosphere 1. Consists of all the parts of the planet that are inhabited by living things 2. Includes most regions of land; most bodies of water and the atmosphere to an altitude of several kilometers.

B. Biome – a group of similar ecosystems with the same general type of physical environment Ex: tundra, desert, tropical rainforest

C. Ecosystems 1. An ecosystem is the community of living things in an area, along with the nonliving features of the environment that support the living community. a) Example: A forest (includes various types of trees and plants, animals, microscopic forms of life, soil, water, air, sunlight, etc.)

D. Community – all the populations in an area What makes up the community in you classroom? E. Population – organisms of the same species living in the same area

F. Organisms - are individual living things a) Examples: squirrels, insects G. Organ system – group of organs that work together

H. Organs – composed of one or more types of tissues I. Tissues- group of cells of the same kind J. Cells - life’s basic units of structure and function

The Diversity of Life A. Species 1. A species is a distinct form of life a) ~ 5,000 species of bacteria; ~8,600 species of birds; ~30,000 species of fishes; ~100,000 species of fungi; ~280,000 species of plants; and ~1,000,000 species of insects

B. The 3 domains of Life 1. A domain is the broadest category for classifying life forms 2. There are 3 domains: Archaea, Bacteria, and Eukarya

C. Typical 6 kingdoms