View Learn.Genetics Materials

Evolution: Variation + Selection & Time

Geologic Time in 92 Days

A daily exercise equating geologic time to 92 school days. Paper cut-outs representing 50 million years are introduced each day and build upon one another to create a timeline. A key explaining the events and biologic forms in each 50-million year square is included. This activity integrates with the Geologic Time page from Learn.Genetics.

Learning Objectives
  • Geologic time is immense.
  • Life forms evolve over geologic time.

Geologic Timeline (PDF) (print out and cut into half sheets)

Geologic Timeline Key (PDF)

  1. Designate a 92-day period of time and space to post the timeline.
  2. On the first day, explain that you have equated geologic time to 92 school days. Each day will be equivalent to roughly 50 million years. Introduce timeline portion number one noting any life forms or events present in its representative time period, and post it to the wall.
  3. Repeat each day with the next portion in the sequence, posting it next to the cut out of the of the previous day to build a timeline.
  1. Note the change in life forms along the timeline, do you see any patterns?
  2. Why don't we see much happening in the Pre-cambrian time period?
  3. How do you think these time periods were designated?

Misconception Quiz

A true / false quiz that addresses the common misconceptions about natural selection and evolution addressed throughout the Variation, Selection and Time materials on the Learn.Genetics website.

Use it as a pre-test, post-test , or as a guide to explore the Variation, Selection and Time materials online. Questions 1-10 address the misconceptions discussed in Things You May Not Have Known About Evolution. Questions 11-17 address the misconceptions that are highlighted on the rest of the activity pages of the Variation, Selection and Time module.

Student Pages (PDF)

Answer Key (PDF)

Reproductive Strategies

Compare sexual and asexual reproduction in several organisms.

Learning Objectives
  • There are two modes of reproduction; sexual and asexual.
  • There are advantages and disadvantages to both sexual and asexual reproduction.

Investigating Reproductive Strategies (PDF)