Biology PT1

Biosphere

• Definition: The biosphere is the global sum of all ecosystems. It is the zone of life on Earth, a closed system where organisms interact with each other and their environment.

• Breakdown of Term:

  • Bio: Refers to life.

  • Sphere: Indicates a system or an organ that consists of interconnected elements.

Ecosystem Processes

• Two Main Processes:

  • Cycling of Nutrients: Refers to the movement and exchange of organic and inorganic matter back into the production of living matter.

  • Flow of Energy: Describes how energy is passed through the ecosystem, primarily from sunlight through photosynthesis in producers, to consumers, and finally to decomposers.

  • Photosynthesis: The process by which plants (producers) convert light energy into chemical energy, producing food and oxygen.

Cell Types

• Prokaryotic Cells:

  • Characteristics: Simple cells that lack membrane-bound organelles and a nucleus.

  • Example: Bacterial cells.

• Eukaryotic Cells:

  • Characteristics: Complex cells containing membrane-bound organelles and a true nucleus.

  • Example: Plant and animal cells.

Scientific Method

• Definition: A method of inquiry that involves making observations, forming a hypothesis, conducting experiments, and drawing conclusions based on evidence.

• Inquiry Types:

  • Descriptive Science: Involves collecting qualitative and quantitative data through observation and documentation.

  • Hypothesis-Based Science: Involves forming testable predictions (hypotheses) based on existing knowledge or observations, and then experimenting to test these predictions.

Data Types

• Quantitative Data: Objective measurements that involve numbers (e.g., time spent grooming, temperature).

• Qualitative Data: Subjective observations that may describe qualities (e.g., behavior observed in chimpanzees).

• Inductive Reasoning: Making generalizations based on collected data and observations.

Hypothesis Creation

• Definition: A hypothesis is an educated guess based on prior knowledge and observations. It must be testable and falsifiable.

• Example of a Good Hypothesis:

  • "If plant growth is affected by light, then plants in full sunlight will grow taller than those in the shade."

Experimentation

• Conditions for a Good Experiment:

  • Must have a large sample size (to ensure reliability).

  • Should test only one variable at a time to identify cause and effect.

Control Groups

• Definition: A control group is a baseline group in an experiment that does not receive the treatment, allowing for comparison against the experimental group.

Conclusion Drawing

• Importance of Results: Conclusions must be based on a comprehensive analysis of the gathered data; inaccurate results can arise from small sample sizes or uncontrolled variables.

• Example of a Flawed Study: An interview of only one person for results leading to generalizations is scientifically invalid.

Scientific Theories vs Laws

• Theory: A well-substantiated explanation of some aspect of the natural world, supported by a body of evidence but not universally accepted as fact.

• Law: Describes a universal relationship observed in nature that is consistently repeatable under the same conditions (e.g., Law of Gravity).

Models in Science

• Definition: Models are representations of an idea or system that help in understanding phenomena and making predictions.

• Application: Used in various fields, including biology to predict health outcomes or behaviors without invasive procedures.