Biology IA Ideas: Inspiration for Your Internal Assessment Project

This article guides IB students on crafting successful Biology IAs, from formulating research questions to conducting and analyzing experiments.

Understanding the core components of the Biology IA is crucial for IB students.

This section will guide students through the essential steps of crafting a successful internal assessment, from formulating a research question to conducting an experiment and analyzing the variables involved.


Here are five potential Biology IA (Internal Assessment) ideas:

  1. The effect of different wavelengths of light on the growth rate of a specific plant species. Research question: How do different wavelengths of light (red, blue, and green) affect the growth rate of radish plants (Raphanus sativus) over a four-week period?
  2. The impact of pH levels on the activity of digestive enzymes. Research question: How do different pH levels (pH 2, 4, 6, 8, and 10) affect the rate of starch digestion by salivary amylase enzyme over a 30-minute period?
  3. The relationship between air pollution levels and lichen diversity in urban and rural areas. Research question: How does the diversity of lichen species differ between urban and rural areas with varying levels of air pollution, as measured by the Air Quality Index (AQI)?
  4. The effect of different concentrations of salt on the heart rate of Daphnia magna. Research question: How do different concentrations of sodium chloride (0%, 0.5%, 1%, 1.5%, and 2%) affect the heart rate of Daphnia magna over a five-minute observation period?
  5. The impact of temperature on the respiration rate of yeast. Research question: How do different temperatures (10°C, 20°C, 30°C, and 40°C) affect the respiration rate of baker’s yeast (Saccharomyces cerevisiae) as measured by the volume of carbon dioxide produced over a 30-minute period?

Choosing Your Research Question

Selecting an appropriate research question is the first step in the Biology IA process.

A strong research question should be specific, measurable, and focused on a topic that allows for a thorough investigation.

Students must engage with their chosen topic personally, showcasing curiosity and a deep interest in the subject matter.

The question sets the stage for the entire project and should align with the International Baccalaureate (IB) Biology syllabus, incorporating concepts and skills that have been covered during the course.

Designing Your Experiment

Once the research question is solidified, students must then create a reliable and valid method for their experiment.

The methodological design should include detailed steps that another researcher could easily replicate.

It is important to clearly identify the independent variables, which are the conditions that can be changed or manipulated, and the dependent variables, which are the observed effects resulting from those changes.

Additionally, any control variables should be constant to ensure accurate and valid results.

A microscope and various biological specimens arranged on a lab table.</p><p>Textbooks and scientific equipment are visible in the background

Understanding Variables

A thorough analysis of the variables is essential for any science research.

In a Biology IA, discerning the relationship between independent, dependent, and control variables is paramount for drawing valid conclusions.

Independent variables are the factors that the experimenter changes during the investigation, while dependent variables are the effects that are measured.

Control variables, on the other hand, must be kept constant to prevent them from influencing the outcome of the experiment.

A clear understanding of these elements and their interplay is vital for hypothesis testing and forming a substantiated conclusion.

The selection and execution of experiments in biology can be a fascinating journey into the scientific method.

This section unveils concrete ideas for experiments across various domains of biology, each with unique methodologies and scientific questions.

Experimental Ideas and Implementation

Plant Biology Experiments

Investigating plant biology can involve exploring how light intensity affects the rate of photosynthesis in aquatic plants or examining the effects of salinity on the germination of seeds.

Students may consider an experiment observing how different salt concentrations influence plant growth, which is a practical exploration tied to real-world agricultural issues.

For inspiration, understanding stomatal density in relation to atmospheric CO2 levels provides insight into plant adaptation strategies.

Human Physiology Investigations

In human physiology, ideas might encompass how sugar solutions impact blood pressure or the relationship between BMI and heart rate post-exercise.

A popular IB Biology IA idea could involve measuring reaction times before and after a cognitive task to assess neurological function.

Additionally, understanding the effects of temperature variation on enzyme activity in saliva can reveal much about metabolic processes.

Microbiology Projects

Microbiology projects may focus on the effectiveness of various antibiotics on bacterial growth or the rate at which bacterial colonies develop resistance over time.

Projects studying yeast respiration in different sugar concentrations offer students a window into cellular processes, and using different brands of toothpaste to inhibit bacterial development in milk showcases practical applications of microbiology.

Environmental and Ecological Studies

Under this theme, students can examine the impact of pollution on river ecosystems or the diversity found within distinct environmental niches, observing how species adapt to varying temperatures and CO2 levels.

Projects could also assess how environmental factors like pH and temperature affect the growth rate of algae, providing insights into broader ecological topics like oxygen production and global warming effects.