Natural Selection and Statistics

What is natural selection?

A process by which traits of a population are selected due to inherited differences in the ability of individuals to survive and reproduce.

What is the purpose of a biological life?

To reproduce.

What is “survival of the fittest?”

Individuals that are more fit (have higher fitness) will pass on their genes/traits to future generations more than the individuals less fit.

What is fitness?

An individual’s ability to survive and reproduce.

What is the predator to prey relationship?

If one trait of the prey escalates, the corresponding trait of the predator also escalates.

What is adaptation?

When the average fitness of a population increases over time due to changes in the proportions of various traits.

Why do populations change over time?

Because of competition for limited resources, and individuals with traits that make then better able to survive, and reproduce, spread those traits in the population.

How are you able to measure data that is diverse?

Use small groups with randomization, representatives, and diverse tests.

What are diverse tests when measuring for data?

Sampling various traits of a population (ex: male vs female, old vs young, etc.).

How can we avoid outliers in our data?

Use bigger samples, avoid bias, and calculating the p-value to predict the likeliness or unlikeliness of outliers.

What is p-value?

The probability that something is due to random chance.

What do scientists use as a cutoff in p-value, why is this important?

The cutoff is p-value < 0.05 (less than 5%). Data under a p-value of 0.05 is statistically significant, and there would be a rare chance that the data happened by random chance.

What are the statistical tools used in graphs?

ANOVA (Analysis of Variance), Linear Regression, Chi-Squared, Error Bars.

What are types of selections?

Directional, stabilizing, disruptive, artificial (selective breeding), and sexual selection.

What is directional selection?

One extreme of a trait is selected for, rather than the average or other extreme.

What can you infer in directional selections?

Individuals with that extreme trait are more successful at survival and reproduction.

What is stabilizing selection?

When the average is selected for, rather than either extreme ends.

What can you infer from stabilizing selections?

Individuals with the average trait are selected rather than the extreme.

What is disruptive selection?

Individuals at both extreme ends are selected for, rather than the average.

What can you infer from disruptive selection?

Individuals with either extreme traits are more successful

What is artificial selection, also known as selective breeding?

When people, rather than nature, choose desirable traits in organisms, and breed individuals together based on those traits.

What does artificial selection sometimes oppose to?

Nature.

What is sexual selection (non-random mating)?

When mates are picked based on traits, not by randomness.

What are honest indicators with sexual selection?

Attractive indicators that are real and cannot be faked (ex: big peacock tails mean that peacock is likely more fit).

What is sexual dimorphism in sexual selection?

When male and females have different traits, and they reproduce, they dimorph.

What is the meaning of dimorph?

When either two characteristics or traits of parents are in a single organism (plants or animals).

What does an analysis of variance do?

Determines whether the averages (means) of multiple groups are the same or different.

What does a linear regression do?

Determines whether the correlation (relationship) between two variables is meaningful.

What does a chi-square do?

Determines whether the count (#) of different groups (ex: heads/tails) is the same or different.

What is goodness of fit?

A statistical measure that tells you how well your data matches the values predicted from a theoretical distribution.

What can error bars let us do?

Lets us know how confident we are and if our groups are different or not.