Introduction to biology

Chapter 1: Introduction to Biological Concepts and Research

Why It Matters

  • Questions addressed by biology:

    • How did life originate?

    • How does life persist?

    • How is life changing?

  • Life's existence since nonliving materials formed the first living cells.

1.1 What is Life? Characteristics of Life

  • Common Characteristics of Living Organisms:

    • Composed of biological molecules with building instructions.

    • Gather energy/materials for growth, repair, and reproduction.

Characteristics of Life (cont.)

  • Response to Environment:

    • Organisms alter their chemistry and activities to survive.

  • Generational Change:

    • Structure and function can evolve across generations.

Living Organisms vs. Inanimate Objects

  • Both are composed of atoms and molecules that obey physical laws.

Emergent Properties

  • Hierarchy of Life:

    • Organization from complex biological molecules to living organisms.

    • Emergent properties are characteristics not present at lower organization levels.

Levels of Organization

  • Hierarchy Breakdown:

    1. Cell: Lowest unit that can survive/reproduce.

    2. Tissue: Groups of cells.

    3. Organ: Group of tissues.

    4. Organ system: Group of organs.

    5. Organism: Individual living entity.

    6. Population: Group of the same species.

    7. Community: Different populations in a specific area.

    8. Ecosystem: Community plus nonliving environmental factors.

    9. Biosphere: All Earth’s ecosystems and life zones.

Chemical Instructions

  • DNA:

    • Contains assembly instructions for organisms.

    • Double-stranded helical structure.

Pathway of Information Flow

  • DNA -> RNA -> Protein:

    • DNA instructions copied into RNA, guiding protein synthesis.

    • Proteins perform most life activities.

    • DNA self-replicates for inheritance.

Metabolic Activities

  • Metabolism Definition:

    • Extraction and use of energy from the environment.

  • Photosynthesis:

    • Conversion of sunlight into chemical energy in plants.

  • Cellular Respiration:

    • Breakdown of biological molecules to release energy.

Producers, Consumers, Decomposers

  • Roles in Ecosystems:

    • Producers: Photosynthetic organisms create food.

    • Consumers: Animals that feed on producers.

    • Decomposers: Bacteria/fungi recycle nutrients from dead matter.

Energy Flows – Matter Cycles

  • Energy Flow:

    • Sunlight energy supports life; some lost as heat during transfer.

  • Nutrient Cycling:

    • Matter like carbon and nitrogen cyclically used in ecosystems.

Compensating for Environmental Changes

  • Only living organisms sense changes and respond appropriately.

  • Diversity of receptors detects internal/external conditions.

Homeostasis

  • Definition:

    • Regulation of internal conditions (e.g., temperature) despite external changes.

Reproduction and Development

  • Reproduction Process:

    • DNA transmission from parents to offspring.

    • Development: Changes from fertilized egg to adult.

Life Cycle of an Atlas Moth

  • Stages include:

    • Egg

    • Larva

    • Pupa

    • Adult

Populations Change Through Generations

  • Biological Evolution:

    • Populations undergo changes in DNA across generations.

1.2 Biological Evolution

  • Key understandings:

    1. Change over time: Populations evolve.

    2. Common ancestry: All organisms share ancestors.

    3. Evolution diversity: Evolution produces life's variety.

Darwin and Wallace

  • Observations:

    • Fossil evidence of species resembling living forms.

    • Species change form across generations.

Natural Selection

  • Key Observations:

    • Breeding demonstrates selections in domestic species.

    • Natural selection akin to artificial selection.

Darwin and Wallace (cont.)

  • Observations Summary:

    1. High offspring production.

    2. Environmental survival factors.

    3. Heritable variations contribute to success.

    4. Favorable traits become prevalent.

Mutations in DNA

  • Source of Variability:

    • Mutations provide genetic diversity and adaptations.

Adaptations

  • Characteristics enhancing survival:

    • Example: Coloration adaptations in rock pocket mice aiding in camouflage.

1.3 Biodiversity and the Tree of Life

  • Species Definition:

    • Similar structure/behavior; can interbreed.

  • Genus Definition:

    • Group of similar species.

Hierarchical Classification

  • Classification order:

    • Species > Genus > Family > Order > Class > Phylum > Kingdom > Domain.

The Tree of Life

  • Phylogenetic Trees:

    • Illustrate evolutionary pathways and relationships among species.

Three Domains

  • Major domains:

    1. Bacteria and Archaea: Prokaryotes, no defined nucleus.

    2. Eukarya: Eukaryotic cells with distinct nucleus.

Domain Bacteria

  • Characteristics:

    • Microscopic, unicellular, widespread metabolic processes.

Domain Archaea

  • Characteristics:

    • Microscopic, unicellular, extreme environments.

Domain Eukarya, Kingdom Protoctista

  • Characteristics:

    • Includes unicellular/multicellular organisms like protozoa/algae.

Domain Eukarya, Kingdom Plantae

  • Characteristics:

    • Multicellular, mostly photosynthetic producers.

Domain Eukarya, Kingdom Fungi

  • Characteristics:

    • Decomposers that absorb nutrients from dead organisms.

Domain Eukarya, Kingdom Animalia

  • Characteristics:

    • Multicellular, active movement at some life stage.

1.4 Biological Research

  • Types of Research:

    • Basic: Understanding phenomena, no practical goal.

    • Applied: Solving specific problems, like drug development.

The Scientific Method

  • Process:

    • Observation, hypothesis development, testing predictions, data collection.

    • Publication for verification and repeatability.

Multiple Choice Review Questions

  • Highlights key concepts related to biology and evolutionary principles, testing understanding of the material.