The Evolving Lesson Plan: Events, Eras and Extinctions

May 21, 2010 at 3:13 PM Leave a comment

Thank goodness 1st period are such sweet guinea pigs while I stumble through a less than great lesson and do better next time. Or the time after that. Maybe even getting it to okay by 7th period…. 

Sharing their pictures about the eras, events and extinctions around the ribbon of time:

All crowded in the last 10% of time…

And the lonely people representing the start of life, start of photosynthesis, complex cells and most exciting, the evolution of sexual reproduction followed by multicellular life. You can only see complex cells, sex and multicellular life starting in this pic!

By third period, had students write down interesting stuff about the history of life on earth that they learned from each part of today’s class. Kept them more focused.

I am frustrated by how many students did not do this homework – need to concentrate on those who DID and let it go with a “0” being given without the recrimination. Really, lighten up (note to me).

Went over the cladogram of life, another way of reviewing the same content in a pretty graphic format.

Then had them trace the mass extinctions graph in later periods. What do you notice? – general upward trend of biodiversity with periodic mass extinctions. Look at the ribbon. Each mass extinction clears the way for an ‘explosion’ of new life forms.

The ribbon of time shows the relationship between mass extinction and the heralding of a new era ex. the age of reptiles after the mass extinction 248 mya, the age of mammals after the K/T extinction of the dinosaurs.

And the 6th great extinction slated to lose 50% of species by the end of the century added to the graph is a larger drop and a faster drop than any other previous mass extinction, including the Permian catastrophe. It’s truly terrifying.

But also considered the other big question of our times: Which came first, the chicken or the egg? Much speculation…. sexual reproduction requiring a egg or female cell started 1.2ish billion years ago. Birds evolved about 1.6 MILLION years ago. So duh, eggs 🙂 glad we’ve got that straight.

The walk through time was hard work, keeping them focused and the energy up. There were so many major errors in their presentations, that we will have to re-consider the use of the Tour Through Time. It’s too dense, too confusing. The text is way too brief and does not mention the evolution of sex. Maybe too rude for a Ca state text?? Need to make the titles of their assignments fit more specifically the sections of what ever text they use or they are lost.

Lots of misconceptions about bacteria vs complex cells. Sigh. Taught at the start of the year. 0 carry over. Little memory of the protist in pond scum lab. Should shoot self now. Or maybe just show movies for first part of school year? Until you get to multi cellular organisms, they think its volcanoes all day all the way.

By the end of the day, I figured out that they can only really concentrate in class and used the ribbon of time for their presentations instead of going outdoors down the freezing breeze way:

Then we did a “Run through Time” with just the dates and events. Much more fun! So next year, yeah!

Entry filed under: Evolution. Tags: , , , , .

The Timeline of Life – Millions and Billions of Years So Many Fossils, So Little Time!

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