Introduction to Biology

Study Notes

Introduction to Biology

Biology is the scientific study of life and living organisms, including their structure, function, growth, origin, evolution, and distribution.
It encompasses a vast field, including subdisciplines like botany, zoology, microbiology, genetics, and ecology.
The fundamental unit of life is the cell.
All living organisms are composed of cells, which perform essential life functions.

Characteristics of Living Organisms

Living organisms share key characteristics distinguishing them from non-living things:
- Organization: Complex, highly structured.
- Metabolism: Acquire and use energy for life processes.
- Growth and development: Cells multiply, organisms grow and mature.
- Adaptation: Organisms adjust to their environments, often across generations.
- Response to stimuli: React to internal or external changes.
- Reproduction: Produce offspring, either sexually or asexually.
- Homeostasis: Maintain a relatively stable internal environment.
- Evolution: Gradual change in populations over generations.

Cell Structure and Function

Cells are the basic structural and functional units of life.
Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
Eukaryotic cells (plants, animals, fungi, and protists) have a nucleus and membrane-bound organelles, enabling compartmentalized functions.
Key organelles include the nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, and vacuoles.
Specific structures enable varied functions, from energy production to protein synthesis to waste removal.

Genetics

Genetics studies heredity and inherited trait variations.
DNA (deoxyribonucleic acid) is the hereditary material in most organisms.
Chromosomes, containing DNA and proteins, carry genetic information.
Genes are DNA segments coding for proteins, expressing traits.
Meiosis and mitosis are crucial cell division processes for reproduction and growth.

Ecology

Ecology studies interactions between organisms and their environment.
Ecosystems are complex systems combining biotic (living) and abiotic (non-living) components.
Ecological principles include energy flow, nutrient cycling, biodiversity, and population dynamics.
Key ecological levels are individuals, populations, communities, and ecosystems.

Evolution

Evolution is the process of population change over generations.
Natural selection is a key mechanism—organisms with advantageous traits survive and reproduce more successfully.
Genetic variation and mutations contribute significantly to life's diversity.
Evolutionary theory explains the unity and diversity of life on Earth.

Classification

Organisms are classified into hierarchical groups based on shared characteristics.
The taxonomic system, from broadest to narrowest, includes Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.
This system systematically arranges and names organisms.

Important Biological Processes

Photosynthesis, used by plants and some other organisms, converts light energy into chemical energy (sugars).
Cellular respiration breaks down food molecules to release energy.
These fundamental processes are crucial for organism survival.

Branches of Biology

Various specialties exist within biology:
- Botany (plant study)
- Zoology (animal study)
- Microbiology (microorganism study)
- Genetics (heredity study)
- Ecology (organism-environment interactions)
- Physiology (living organism functions)
- Molecular Biology (biomolecule structure and function)

Biomolecules

Living organisms comprise diverse biomolecules: carbohydrates, lipids, proteins, and nucleic acids.
These molecules play vital roles, from forming cell structures to catalyzing reactions.

Description

Explore the fascinating world of biology, the scientific study of life and living organisms. This quiz covers essential concepts such as cell structure, metabolism, growth, adaptation, and the key characteristics that distinguish living organisms from non-living things.