biology
Page 2: Biology – The Study of Life
Life arose more than 3.5 billion years ago.
First organisms were single-celled.
Only life on Earth for millions of years.
Organisms changed over time (evolved).
New organisms arose from older kinds.
Today, there are millions of species inhabiting almost every region of Earth.
Page 4: Themes of Biology
Cell Structure and Function
Stability and Homeostasis
Reproduction and Inheritance
Evolution
Interdependence of Organisms
Matter, Energy, and Organization
Page 5: Cell Structure and Function
Cells are the basic unit of life.
All organisms are made of and develop from cells.
Some organisms are unicellular, usually identical to the parent.
Most organisms are multicellular.
Cells undergo differentiation.
Cells are small and highly organized.
Page 8: Stability and Homeostasis
Organisms must maintain stable internal conditions (homeostasis).
Key factors include temperature, water content, and chemical content.
Page 9: Reproduction and Inheritance
All organisms reproduce.
Organisms transmit hereditary information to their offspring.
Page 10: DNA
DNA (Deoxyribonucleic Acid) contains genetic information.
Instructions for traits are found in genes.
DNA is identical in every somatic cell.
Page 11: Sexual Reproduction
Involves combining hereditary information from two organisms.
Egg and sperm form a zygote, containing information from both parents.
Page 12: Asexual Reproduction
Involves one organism dividing to produce identical offspring.
Genetic information is from a single parent.
Page 13: Evolution
Populations change over generations.
Explains the existence of different species and their relationships to past organisms.
Page 15: Natural Selection
Driving force in evolution.
Organisms with favorable traits reproduce more successfully.
Leads to gradual changes in populations over generations.
Page 17: Interdependence of Organisms
Organisms interact with each other and their environment (ecology).
Example: Insects and flowers depend on each other for food and pollination.
Page 19: Matter, Energy, and Organization
Living things are highly organized and require energy.
All energy originates from the sun.
Photosynthesis converts solar energy into chemical energy.
Page 21: Autotrophs
Organisms that produce their own food.
Phototrophs: Use solar energy (photosynthesis).
Chemotrophs: Use chemical processes for energy.
Page 22: Heterotrophs
Organisms that consume food for energy.
Includes herbivores, carnivores, and omnivores.
Page 24: Characteristics of Life
All living things are composed of cells.
Multicellular organisms have specialized cells.
Size depends on the number of cells, not their size.
Page 30: Homeostasis
Organisms maintain stable internal conditions (e.g., temperature, pH).
Page 31: Growth
Growth occurs through cell division and enlargement.
New cells arise from preexisting cells.
Page 33: Reproduction
Essential for the continuation of a species, not individual survival.
Page 34: Responsiveness
Organisms respond to external stimuli (light, heat, sound).
Page 35: Evolve
Ability to adapt through evolution.
Favorable traits are passed on to offspring (adaptations).
Page 36: Scientific Method
Steps include:
Ask a Question
Make Observations
Form a Hypothesis
Test the Hypothesis
Analyze Results
Draw Conclusions
Communicate Findings
Page 39: Forming a Hypothesis
A testable statement predicting results.
Often refined or discarded based on evidence.
Page 41: Experimenting
Testing hypotheses under controlled conditions.
Comparison of control and experimental groups.
Page 46: Conclusion
Based on facts, not observations.
Should support the hypothesis and be re-testable.
Page 49: Theories
Formed after multiple hypotheses are tested and supported.
Comprehensive statements supported by evidence.
Page 50: Laws
Statements of fact explaining actions or groups of actions.
Universally accepted and may be expressed mathematically.
Page 52: Microscopy and Measurement
Microscopes enlarge images for studying organisms and cells.
Magnification and resolution are key features.
Page 54: Compound Light Microscopes
Used for live specimens.
Magnification up to 1000X.
Page 56: Electron Microscope
Produces high magnification images (up to 200,000X).
Cannot view living specimens.
Page 59: Measurements
Use of SI units (metric system) for consistency in scientific m