Week 1 AP Bio 25-26

Role of a negative control in an experiment

• Helps confirm that any observed effect is due to the variable being tested.

• Is used to increase the sample size of the experiment.

• Acts as a substitute for the experimental group.

• Provides a baseline for comparison with the positive control.

What are the four Big Ideas (themes) in AP Biology, and what does each one emphasize?

• 1. Evolution, Information Storage and Transmission, Energy and Matter Flow, Systems and System Interactions

• 1. Genetics, Ecology, Physiology, Evolution

• 1. Homeostasis, Reproduction, Development, Adaptation

• 1. Structure and Function, Diversity of Life, Interdependence, Change over Time

Determining the dependent variable in an experiment

• The dependent variable is what you measure or observe as a result of the experimental treatment.

• The dependent variable is the factor that is changed or controlled in a scientific experiment.

• The dependent variable is the variable that remains constant throughout the experiment.

• The dependent variable is the initial condition set before the experiment begins.

Purpose of comparing results to a hypothesis predicting no change

• To determine if their data shows an effect beyond random chance.

• To confirm that the hypothesis is always correct.

• To ensure that the experiment was conducted properly.

• To identify any potential errors in data collection.

Type of relationship where two species benefit from interacting

• Commensalism — one species benefits while the other is neither helped nor harmed.

• Parasitism — one species benefits at the expense of the other.

• Mutualism — a type of symbiosis where both organisms benefit.

• Competition — species compete for the same resources.

Characteristics of a scientific hypothesis

• Must be testable and falsifiable.

• Can be based on personal beliefs.

• Should be vague and open to interpretation.

• Must be proven true before testing.

Key components when designing an experiment on plant growth

• Identify independent and dependent variables, control group, and how to measure growth.

• Choose the right type of soil and water amount.

• Select the best time of year for planting.

• Use only one type of plant for the experiment.

Purpose of a null hypothesis

• Provides a baseline prediction of no effect, helping scientists test statistical significance.

• Indicates the presence of a significant effect in the data.

• Suggests that all observed effects are due to random chance.

• Serves as a guideline for data collection methods.

Levels of organization in biology from smallest to largest

• Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

• Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere → Molecule → Organelle

• Organism → Population → Community → Ecosystem → Biosphere → Molecule → Organelle → Cell → Tissue → Organ → Organ System

• Molecule → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

Biological principle of structure and shape

• Function determines form

• Form determines function

• Structure is irrelevant to function

• Shape has no impact on biological roles