Gene Pools (AHL portion of IB Topic D4.1)

Essential Idea(s): Life evolves. Variations in genes result in variations in traits. Some of those traits end up giving certain organisms an advantage at survival. Environments change, too – so the ability to adapt and evolve is essential for life on earth.

Unit Length: 3 AHL Lessons

  Guiding Questions

◊ What processes can cause changes in allele frequencies within a population?

◊ What is the role of reproduction in the process of natural selection?

Materials:

Self-Teaching Slides (AHL) Quizlet Vocab Set
Notes Template (AHL)

 

IB Statement(s) and Objective(s)

 

D4.1.9: Concept of the gene pool

  • Define gene pool
  • Describe how it is possible for multiple gene pools to exist in a single species
  • Define gene flow
  • Outline the effects of gene flow on genetic diversity

 

D4.1.10: Allele frequencies of geographically isolated populations

  • Define allele frequency
  • Outline how to calculate allele frequencies
  • Use a database to search for allele frequency of a human gene

 

D4.1.11: Changes in allele frequency in the gene pool as a consequence of natural selection between individuals according to differences in their heritable traits

  • Define “neo-Darwinism”
  • State that change in the allele frequencies of a gene is evidence of evolution
  • List processes that can change allele frequency in a population
  • Outline mutation / gene-flow / non-random mating / genetic drift and/or selection as mechanisms that can cause change to allele frequencies  

 

D4.1.12: Differences between directional, disruptive and stabilizing selection

  • Outline the change in allele frequencies associated with stabilizing, disruptive and directional selection
  • Give an example each of stabilizing, disruptive, and directional selection

 

D4.1.13: Hardy–Weinberg equation and calculations of allele or genotype frequencies

D4.1.14: Hardy–Weinberg conditions that must be maintained for a population to be in genetic equilibrium

  • State the Hardy-Weinberg equation and outline its use in ecological investigations 
  • Explain how the Hardy-Weinberg equation can be used to infer the presence of evolutionary forces for a specific trait in a population
  • Given data, calculate allele frequencies of genes in a gene pool
  • Outline conditions necessary for the Hardy-Weinberg equation to be at equilibrium

 

D4.1.15: Artificial selection by deliberate choice of traits

  • Define artificial selection
  • Use an example to explain how selective breeding has led to evolution in a species
  • Explain the process of artificial selection using selective breeding
Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it /  Ӕ = The academy  / Ⓡ = Read it

Ⓛ (Recommended): You are a Hungry Crab (chocolate barnacles lab) (👫 max 3)

Imagine that you are a hungry crab in search of your favorite snack: barnacles. You get to do some actual eating in this lab, but make sure you keep it to the directions per this lab. Log your data carefully and then use the Hardy Weinberg equation to answer all questions at the end of the lab.

 

Ⓛ (Role Play): Class Predator / Prey (👫👫👫 whole class)

Sometimes, an old-fashioned role play is the best way to learn a new topic. Take on the role of class predator or prey and see how populations can change over time. Complete the role play, then use the class data to answer the questions on Slide 6. 

Ⓛ (Simulation): Hawks vs. Mice (👫 max 2)

Play with this simulation so that you feel confident in how it works. Record a screencast of the simulation in action, explaining the key steps of Natural Selection as you go (cover all of the ICE AGE components). Make sure you also explore the alleles of the mice populations — show how one allele becomes the most frequent, depending on the beach vs. field environment.  

 

Ⓛ (Simulation): The Rabbits vs. the Wolves (👫 max 2)

Play with this simulation until you are confident with how it works. Then, complete this accompanying worksheet. Make sure you track all the data and thoroughly answer the questions at the end. 

 

Ⓛ (Simulation): Modeling Darwin’s Finches (👫 max 2)

To begin, print out this sheet (or ask me to) – you will use the (+) and (-) as representations of alleles within a finch population. See how they evolve when you simulate a change in the environment. Follow the instructions to complete the lab and answer all accompanying questions.

 

📄: Out of the Ashes: The Dawn of Mammals (💁)

The violent meteor impact 65 million years ago was a bad thing for dinosaurs – it marked the end of their very long dominance of Earth. It was – fortunately for us – a very good thing for the future of mammals. Watch this 15-minute video to find out how mammals became the dominant creatures following the impact, and complete this accompanying worksheet.