Chapter 1: lecture
Study of Life
Introduction
Focus on Snowy Owl to illustrate concepts.
Example of adaptations for survival in its environment.
Characteristics of adaptations:
Insulation from feathers for subzero conditions.
Keen vision for locating prey.
Importance of adaptation in all organisms.
Concept will recur in discussions of homeostasis and Darwin's theory.
Common Themes in Biology
Definition of Biology:
"Bio" means life; "-ology" means study of.
Therefore, biology is the study of life.
All forms of life share common properties:
Organisms have certain characteristics that fit into being a living entity.
Properties of Life: These are seven characteristics discussed in detail.
Order: Life exhibits a highly ordered structure (e.g., sunflowers show structured order).
Reproduction: The ability of organisms to reproduce their own kind. E.g., elephants and their offspring.
Growth and Development: Consistent growth controlled by inherited DNA, which encodes traits.
Energy Processing: All organisms process energy (e.g., cellular respiration in animals, photosynthesis in plants).
Regulation: Organisms maintain stable internal conditions (homeostasis) despite environmental changes (e.g., body's temperature).
Response to Environment: Ability to respond to environmental stimuli.
Example: A Venus flytrap reacting to a dragonfly.
Evolutionary Adaptation: Traits advantageous for survival increase over generations through reproduction.
Hierarchy of Organization in Life
Life is organized into different levels, from biosphere to molecular level.
Each level has a unique organization but contributes to the whole system.
Order of organization from largest to smallest:
Biosphere: Environments supporting life (e.g., Florida).
Ecosystem: Community of organisms and the environment (e.g., Florida Everglades).
Community: All organisms in a specific area.
Population: A specific species in a community (e.g., alligators).
Organism: Individual living entity (e.g., American alligator).
Organ System: Systems made of multiple organs working together (e.g., cardiovascular system).
Organ: Structure made of tissues performing specific functions (e.g., heart, brain).
Tissue: Group of similar cells performing a particular function (e.g., muscle tissue).
Cell: Basic unit of life, where properties of life emerge (fundamental unit).
Organelle: Membrane-bound structures within cells that perform specific functions (e.g., nucleus).
Molecule: Groups of atoms bonded together (e.g., DNA).
Emergent Properties
New properties arise at each organizational level due to component interactions.
Types of Cells
Prokaryotic Cells:
First to evolve, simpler and smaller.
Lack a nucleus but contain DNA.
Examples include bacteria and archaea.
Eukaryotic Cells:
Larger, more complex, found in animals, plants, fungi, and protists.
Contains membrane-bound organelles, including a nucleus housing DNA.
All cell types:
Enclosed by membranes regulating material passage
Contain DNA as genetic material.
Biological Systems and Processes
Systems Biology studies biological systems and their behavior.
Interactions with environments include non-living and other organisms.
Three components of ecosystems:
Producers: Make their own food (e.g., plants).
Consumers: Rely on others for food (e.g., animals).
Decomposers: Recycle nutrients in the ecosystem.
Energy Flow:
One-way flow from the sun through producers (plants), to consumers, and exits as heat.
Chemical Cycling: Nutrients are recycled in an ecosystem (e.g., through decomposition & absorption by plants).
Evolution
Darwin's Theory (published in 1859):
Species descend from ancestral species through "descent with modification."
Natural selection: Mechanism for evolution based on favorable traits.
Two key observations:
Variation: Individuals vary in traits inherited from parents.
Overproduction: More offspring produced than can survive, leading to competition.
Natural Selection:
Individuals with advantageous traits survive and reproduce more.
Example of natural selection illustrated with beetles of varying colors in a specific habitat.
Scientific Inquiry
Hypothesis: A testable explanation for observations.
Must be able to contribute to data collection and analysis.
Data Types:
Qualitative Data: Descriptive, non-numeric.
Quantitative Data: Numeric measurements.
Scientific Reasoning
Inductive Reasoning: Drawing generalizations from many specific observations.
Deductive Reasoning: Specific predictions based on general premises.
Common Experiments and Variables
Control experiments help test hypotheses with defined control groups.
Example: Beach mouse color adaptation experiment demonstrating survival through camouflage.
Conclusion on Evolution and Artificial Selection
Natural Selection vs. Artificial Selection:
Natural selection occurs naturally; artificial is driven by human choice.
Impacts include genetic variation in crops and animals.
Ethical implications arise from technologies rooted in biology, including genetic modifications and treatments (e.g., IVF).
Final Notes
Emphasis on understanding interactions, systems, and the overarching principles of biology as they relate to life's complexity, adaptation, and evolution.