Introduction to Life Science

Study Notes

Life science is the study of living things
Lesson topics include the concept of life, theories of the origin of life, and unifying themes of life
Learning outcomes include discovering the origin of life, learning about unifying themes of life, and creating an ecosystem

Life is defined as any system capable of performing functions like eating, metabolizing, excreting, breathing, moving, growing, reproducing, and responding to external stimuli
Life properties include a definite form and limited size, a limited lifespan, being made up of one or more cells, using only chemical energy, and having adaptation

Nutrition: Metabolism, the sum total of chemical reactions in an organism
Movement: Ability of an organism to move
Respiration: Anabolism, building up process
Excretion: Process of removing waste and excess water from the body
Growth: Increase in size and number
Sensitivity: Ability to respond to environmental stimuli
Reproduction: Ability of living things to produce new individuals closely resembling them

Unicellular Organisms: Made up of a single cell that carries out all necessary functions (e.g., Paramecium, Amoeba, Bacteria, Yeast)
Multicellular Organisms: Use many different cells to function (e.g., Insects, Humans, Plants)

Special Creation Theory: Life was created by a divine being or supernatural power
Spontaneous Generation Theory: Living organisms arise from non-living things
- Francesco Redi (1668): Experiment disproved spontaneous generation of maggots, showing they came from fly eggs
- John Needham (1745): Challenged Redi's work, arguing boiling could kill microorganisms
- Lazzaro Spallanzani: Designed experiments showing only exposed broth produced microorganisms
- Louis Pasteur: Further experiments disproved spontaneous generation, demonstrating contamination came from the air
Other Theories:
- Beneath the Ice: Ice protected early compounds, allowing interaction to create life
- Lightning: Produced simple sugars and amino acids from simple elements
- Panspermia: Life came from outer space
- RNA World Theory : RNA was the first genetic material

Biological Systems: Living things function as an integrated system that cannot be separated from non-living things
Cellular Basis of Life: Cells are the fundamental units of life
Form and Function: Organism's structures fit with its functions
Reproduction and Inheritance: Traits of parents are passed to offspring
Interaction with the Environment: Survival depends on interactions with the environment
Energy and Life: Organisms use energy for processes; autotrophs use photosynthesis, and heterotrophs consume other organisms
Regulation/Homeostasis: Maintaining a stable internal environment
Adaptation: Ability to adjust to changing environments, fundamental to survival
Evolution: Change over time, leading to biodiversity
Biology and Society: Science changes the lives of organisms, impacts medicine, agriculture, environment, humans
Further study considers how modern biology changes everyday human life