Anhinga

A Natural Selection & Genetics Activity

Anhinga• Anhinga are a species of bird which live

on/near warm water. They are sometimes called “knifebills” because of the unique shape of their beak.

Feeding• The knife-like beak is an adaptation for this

species because it allows the birds to stab fish, which they carry back to their nest to eat.

Environmental Catastrophe• Recently, an oil spill occurred near a group of

Anhinga living on an island. As a result, many of the fish have died, and the water has become very dirty and dangerous.

New Food• Since fish are now harder to find, Anhinga

have started eating insects to get the protein they need.

Dominant & Recessive• The “knifebill” is the most common (and the

dominant) trait for this anhinga population. However, occasionally a recessive spoon-like bill shows up in the population.

Generation 1• Half of you have a homozygous dominant genotype (left

side of room)• Half of you have a heterozygous genotype (right side of

room)• What are your phenotypes?(Write all this down under Generation 1 on your worksheet)

Data• Record the number of each phenotype on

your page for the start of Generation 1

The Rules• You will have 5 seconds to collect as much

“food” as you can.• Food must be picked up and placed into your

nest with your beak.– No picking up the food container– Hold your “food pouch” to your belly

• When time is called, count the number of “insects” you collected.

Life or Death• The top 2/3 of the class will survive and

become parents in Generation 2.• The bottom 1/3 are dead.

Generation 2: Making Babies!• Those who survived must pair up (gender doesn’t

matter).• These two parents will produce ONE baby.– Find one baby from those who died.

• Work together (all 3 of you) to create a Punnett Square showing the possible offspring based on both parents.

WARNING• Remember that EVERYONE must do each step

on their own worksheet.• Even if you died, you must show the Punnett

Square of your new parents.

Rebirth• Spin a large paper clip to determine which

box/genotype the baby actually gets.– Hint: Center the paper clip with the back end of

your utensil or a pencil, then flick it with your finger to spin it.

Baby Phenotypes• Babies must now choose the proper beak type

(utensil) for their genotype:AA = KnifeAa = Knifeaa = Spoon

Genotypes & Phenotypes• Write down your Genotype• Write down your Phenotype• Record the whole-class phenotype numbers for

Generation 2 in the chart on page 1.

Feeding Competition #2• You will have 5 seconds to collect as much

“food” as you can.• Food must be picked up and placed into your

nest with your beak.– No picking up the food container– Hold your “food pouch” to your belly

• When time is called, count the number of “insects” you collected.

Life or Death• The top 2/3 of the class will survive and

become parents in Generation 3.• The bottom 1/3 are dead.

Generation 3-5Repeat 3 more times (or as time permits):1. Make Babies – Pair up and find a baby– Create Punnett Square and spin paperclip

2. Record Data– Your Genotype– Your Phenotype– Class Phenotype Data

3. Food Competition & Counting4. Life or Death

Graphing• Use the Class Phenotype Data chart to create

a line graph of the number of Knifebills and Spoonbills over time (generations).

Reflection Questions• Answer the Reflection Questions on your worksheet.

1. What type of variation existed within the anhinga population?

2. What does "survival of the fittest" mean?

3. How was this simulation similar to natural selection in the wild?

4. How was this simulation different from natural selection in the wild?

5. What adaptation allowed the most anhinga to live in the last 2 generations? Why?