Study of Biology

What is Biology? Biology is the study of all living things Living things are called organisms Organisms include bacteria, protists, fungi, plants, & animals

All Living Things Share Common Characteristics Basic Unit is the Cell They Reproduce All Based On Universal Genetic Code (DNA) Grow & Develop

Common Characteristics Obtain & Use Materials & Energy Respond To Their Environment Maintain A Stable Internal Environment AS A GROUP, Living Things Evolve, That Is They Change Over Time

Characteristics of Organisms

All Organisms are made of Cells

copyright cmassengale 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 copyright cmassengale

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

Organisms are Grouped by their Number of Cells Unicellular Organisms Living Organism Made Up Of One Cell Multicellular Organisms Living Organism Made Up Of Many, Specialized Cells

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

Cells Have a Genetic Code

Genetic Code DNA (deoxyribose nucleic acid) carries the genetic code for all organisms All organisms contain DNA DNA codes for the proteins that make up cells & do all the work

Organisms Grow & Develop

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

Cells Require Food & Energy

Food Requirements Autotrophs can make their own food Photoautotrophs use sunlight to make food (photosynthesis) Chemoautotrophs use chemicals such as iron & sulfur as their energy

Food Requirements Heterotrophs can NOT make their own food They must consume other organisms Herbivores eat plants Carnivores eat meat Omnivores eat plants & animals

Metabolism Sum of all the chemical reactions in an organism All require energy Sunlight is the ultimate energy for life on Earth

Metabolism Cellular Respiration Cells releasing the chemical energy stored in foods 6O2 + C6H12O6 6CO2 + 6H2O

Organisms Respond to Stimuli Organisms Respond to stimuli (Temperature, Water, Food Supplies, etc.) In Order To Survive & Reproduce

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

Living Things Evolve Groups Of Organisms (Not Individuals) Change Over Time In Order To Survive Within Changing Environments. Fossil records show changes in groups of organisms

Life is Organized on Several Levels

Levels Atoms Molecules Organelles Cells – life starts here Tissues Organs System Organism

Levels Population Community Ecosystem Biosphere