# Basic math biologist should know by heart

Here’s my list of basic math biologists that will help a biologist understand fundamental biological principles and be able to broadly read the literature. If you are working in statistics or modelling or a specialist area that is math heavy, you will obviously need to know much more.

This is a work in progress. I will keep updating this list, so message me if you have more to add (or remove!).

## Proficiency at counting

Counting might seem so basic a skill it is not worth mentioning, but counting accurately in the field and lab takes practice. Try counting penguins in a colony of thousands, cells under a microscope, or a moving school of fish and you’ll know what I mean. If you are going to work on any abundant organism, you will need to count well.

You get bonus credentials if you can count and keep track of multiple categories in your head at the same time (if you want to practice this, just get the ebird app go to a local park and try counting as many bird species as you can without looking at your phone)

## Adept at handing different measurement scales

We often converting among different measurement scales, whether it be length scales, concentrations, areas or volumes. Obviously this requires ability at adding, subtracting, multiplication and division. I find areas and volumes often trip people up, so I don’t take this knowledge for granted.

## y = ax + b

The linear equation is ubiquitous in biology and especially statistics. Bonus credentials for understanding y = ax + b + error

It is helpful to understand this equation well, such as how to calculate the slope of a line from two coordinates and how to find the x or y intercept.

## Calculate distances and areas

Primarily in 2 dimensions, but bonus points for three dimensions.

## Logs and powers

Because why multiply when you can add?

It’s useful to know what a base is, that log(0) is undefined, how log10(x) relates to 10^x, that log(1) = 0, log of a number <1 is negative, log of a number more than 1 is positive, that log(a*b) = log(a) + log(b) and that log(a+b) doesn’t equal log(a) + log(b).

## Exponential growth and the exponential equation

Exponential growth and decline are particularly common in biology (and physics, and finance, and economics…), from temperate dependent rates to population growth.

## Intuitive understanding of probability and uncertainty

This means being able to think about the future (or the outcome of an event or experiment) in probabilistic terms, rather than definitive terms. Biology is ruled by lady luck, not by fate.

## Conditional probability

This is fundamental to statistics, but also to thinking about the outcomes of experiments.

## Rules of probability

Including additive rule, multiplicative rule and the meaning of independence and conditional independence.

## Derivates and integrals

It is helpful to know that a derivate defines a rate and that an integral relates to a sum. This will help you read and understand modelling papers better. I don’t think non-modelling biologists need to know the rules of differentiation or integration.

### Tentative list

I’m still thinking about whether I also include: normal distribution (bell curve), central limit theorem, additive property of variances. I haven’t included specialist statistical concepts (e.g. p-values, or bayes theorem), but I think all of the above sets one up to understand those applications of probability. I haven’t included matrix algebra, I don’t think you need to know that unless you are working in modelling or statistics, but message me if you have examples that disagree.

#### Contact: Chris Brown

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