GRE Subject Test: Biology

This subject covers the key concepts and topics tested in the GRE Subject Test for Biology, including cellular biology, genetics, and ecology.

Advanced Topics

Population Dynamics and Evolution

How Populations Change Over Time

Evolution is the process by which species change and adapt across generations. Population dynamics focus on how and why populations grow, shrink, or change.

Key Factors

  • Natural Selection
  • Genetic Drift
  • Gene Flow
  • Mutation

Population Growth

Populations can grow exponentially under ideal conditions, but limiting factors (like food and space) lead to logistic growth.

Logistic Growth Equation

\[ \frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right) \]

Where \(N\) is population size, \(r\) is growth rate, and \(K\) is carrying capacity.

Real-World Significance

Understanding these concepts helps us conserve endangered species and manage natural resources more effectively.

Key Formula

\[\frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right)\]

Examples

  • Bacteria evolving antibiotic resistance in hospitals.

  • Conservationists reintroducing wolves to restore ecosystems.

In a Nutshell

Population dynamics and evolution explain how species adapt, survive, or go extinct over time.