Integrative Physiology and Ecology - Week 1 Lecture 2

Integrative Physiology and Ecology

Concepts of Integrative Physiology and Ecology

  • Definition of Integrative: to form, coordinate, or blend into a functional or unified whole.

    • Vertical Integration: how individual organisms work (focus on physiology).

    • Horizontal Integration: how organisms interact with other organisms and their environment (focus on ecology).

    • Temporal Integration: how organisms change over evolutionary time (focus on evolution).

Scales of Inquiry in Biology

  • Biological viewpoints can be assessed at various levels including:

    • Ecosystem

    • Community

    • Ecology

    • Population

    • Organismal

    • Cellular/Molecular

Biology in Context

Characteristics of Life

  • Complexity: Living organisms exhibit complex structures.

  • Response to Environment: Ability to change in response to environmental stimuli.

  • Reproduction: Capability to produce offspring.

  • Evolution: Capacity to evolve over time as a response to environmental pressures.

Shared Chemical Foundations

  • The living and nonliving worlds share the same chemical foundations and obey the same physical laws. There’s no special distinction in individual chemical components.

Composition of Earth's Crust and Human Body

Earth's Crust Composition

  • Major Components:

    • Oxygen: 46.5%

    • Silicon: 28%

    • Other: 8.3%

      • Aluminum: 8%

      • Iron: 5%

      • Calcium: 4%

      • Hydrogen: 0.14%

      • Phosphorus: 0.1%

      • Carbon: 0.09%

Human Body Composition

  • Key Elements:

    • Oxygen: 65%

    • Carbon: 18%

    • Hydrogen: 10%

    • Nitrogen: 3%

    • Calcium: 1.5%

    • Other: 1.5%

      • Phosphorus: 1%

      • Iron: <0.05%

      • Aluminum: <0.001%

Thermodynamics in Biological Systems

First Law of Thermodynamics

  • Statement: Energy cannot be created or destroyed, only transformed from one form to another.

    • Energy input from sunshine or food undergoes conversion processes to perform work within organisms.

Second Law of Thermodynamics

  • Statemzx ent: The degree of disorder (entropy) in the universe tends to increase over time.

    • As simple molecules combine into complex forms within cells, the internal entropy decreases, requiring energy. However, energy is released as heat, increasing entropy in the environment.

Historical Experiments in Biology

Francesco Redi's Experiment (1600s)

  • Objective: To demonstrate that living organisms arise from other living organisms.

    • Open Jar: Maggots appeared.

    • Gauze-Covered Jar: No maggots appeared, indicating that exposure to air leads to the presence of life.

    • Sealed Jar: Also showed no maggots, supporting the idea of biogenesis.

Louis Pasteur's Experiment (1800s)

  • Hypothesis Rejected: Microbes do not arise spontaneously from sterile broth.

    • Experiment used swan-neck flask versus straight-neck flask to prevent dust which carried microbes from entering the broth. The broth remained clear in the swan-neck flask, affirming that life originates from existing life.

Cellular Biology and the Characteristics of Cells

Essentials of Cells

  • All organisms are composed of single or multiple cells.

  • Key Features of Cells:

    • Ability to store and transmit information (via DNA).

    • Plasma membrane that separates interior from the external environment.

    • Ability to harness energy and materials from the environment.

Types and Sizes of Cells

  • General Characteristics:

    • Most cells are below detection by the naked eye.

    • Average skin cell diameter: approximately 100 microns (0.1 mm).

    • Some nerve cells can have axons up to one meter long.

    • Ostrich eggs represent larger cell examples.

DNA and Information Storage

DNA Structure

  • DNA (deoxyribonucleic acid) is a double-stranded helix composed of four molecular types, encoding a cell’s information through sequence variation.

  • Central Dogma:

    • Processes: DNA undergoes transcription to form RNA, which is translated to produce proteins.

Gene Expression

  • Example: Lens cells utilize DNA information to synthesize transparent proteins, known as crystallin, essential for lens clarity.

Energy Transformation in Living Systems

Energy Acquisition and Metabolism

  • Organisms source energy from:

    • The sun

    • Chemical compounds

  • Metabolism: Refers to the collection of chemical reactions utilized by cells to convert energy and build/break down molecules.

Energy Flow and Chemical Cycling

  • Mechanism:

    • Plants gather sunlight and convert it to chemical energy via photosynthesis.

    • Chemical reactions in organisms convert absorbed energy for work.

    • Heat dissipates, contributing to ecosystem dynamics including waste recycling.

Introduction to Ecology

Definition of Ecology

  • Ecology studies organismal interactions among themselves and with their environment, focusing on features such as:

    • Anatomy

    • Physiology

    • Behavior

Examples of Ecological Interactions

  • Pollination: A bee visits flowers based on color and scent, aiding in pollination.

  • Competition: Trees in rainforests must compete for water and nutrients.

  • Mutualism: Leafcutter ants cultivate fungi using leaf slices, establishing dependability with the plants they harvest.

Human Impact on Evolution

Evolutionary Biology

  • Human actions significantly affect species' evolution and survival, contributing to extinction and changing environmental conditions.