Bio1001_ch01_v4b_students

Chapter 1: Introduction to Biology

Overview

• Course Title: Biology 1001

• Institution: Brooklyn College, CUNY

• Authors: Robert J. Brooker, Eric P. Widmaier, Linda E. Graham, Peter D. Stiling

• Publication: Sixth Edition, McGraw Hill

Definition of Biology

• Biology is the study of life.

Characteristics of Life

• What does it mean to be alive?

  • Life displays a common set of characteristics that differentiate living from non-living entities.

  • Characteristics indicate the functions and abilities of the first living cells.

Unifying Principles of Life

Characteristic #1: Cellular Composition

• All living organisms are composed of cells.

• Cell Theory (Key Points):

  1. All organisms are made of one or more cells.

  2. Cells are the smallest units of life.

  3. New cells arise from pre-existing cells.

• Founders: Matthias Schleiden, Theodor Schwann, Rudolf Virchow.

Characteristic #2: Energy Utilization

• Organisms utilize energy to maintain life processes and growth.

• Organisms maintain an internal environment that requires energy input to sustain.

• Distinction between:

  • Primary producers: e.g., plants, algae harness light energy.

  • Consumers: e.g., animals and fungi that feed on other organisms.

Characteristic #3: Interaction with Environment

• Living organisms interact with and adapt to their environment.

• Example: Mammals grow thicker fur in response to colder temperatures.

Characteristic #4: Homeostasis

• Organisms regulate their internal environment for optimal metabolic processes.

Characteristic #5: Reproduction and Genetic Material

• Organisms must reproduce to sustain life.

• All living organisms possess DNA (deoxyribonucleic acid) that provides a blueprint for organization and function.

Characteristic #6: Growth and Development

• Organisms grow, which involves cell division and differentiation into various cell types.

• Unicellular organisms increase in cell volume through the synthesis of additional components.

Characteristic #7: Evolution

• Evolution refers to the change in populations of organisms over generations, leading to better adaptation to environments.

• Example: Evolution of the long snout in anteaters for food acquisition.

Characteristic #8: Relatedness of Species

• All species are related through common ancestry, indicating a shared tree of life.

Unity and Diversity of Life

1. Unity in Characteristics:

   • All species share fundamental traits that distinguish them from non-living objects.

   • The unity of traits results from evolutionary processes.

2. Diversity:

   • Life exhibits diversity adapted to various environments.

Levels of Biological Organization

• Biological complexity can be analyzed at different levels, with an increase in complexity at each step:

  • Atom (e.g., Carbon atom)

  • Molecule (e.g., DNA)

  • Organelle (e.g., Chloroplast)

  • Cell (e.g., Leaf cell)

  • Tissue (e.g., Epidermis of leaf)

  • Organ (e.g., Leaf)

  • Organ System (e.g., Aboveground part of a plant)

  • Organism (e.g., Acacia tree)

  • Population (e.g., Multiple acacia trees)

  • Community (e.g., Populations in a savanna)

  • Ecosystem (e.g., The savanna)

  • Biosphere (global ecosystem)

Emergent Properties

• Organisms function beyond mere collections of parts; new functions arise from interactions among components.

• Systems Biology: The study of how new properties of life emerge from interactions among individual parts.

Scientific Investigation and Methodology

Two Branches of Science

1. Discovery-based (descriptive) science

2. Hypothesis-based (experimental) science

Discovery-based Science

• Begins with observations about what is unknown (What, Where, When?).

• Goal: Acquire knowledge through exploration.

Hypothesis-based Science

• Starts with questions about known phenomena (How, Why?).

• Involves five stages:

  1. Observation

  2. Questioning

  3. Hypothesis formulation

  4. Experimentation

  5. Data analysis and hypothesis acceptance/rejection

Example Case: Botulism

1. Observation: Leaves fall in autumn; Botulism causes muscle paralysis.

2. Hypothesis: Botulism occurs due to anaerobic conditions in canned food.

3. Experimentation and Data Collection.

4. Conclusion based on statistical significance.

Scientific Theory vs. Hypothesis

• Hypothesis: Proposed explanation based on observations; must be testable.

• Theory: Broad explanation supported by substantial evidence and capable of making predictions.