I like the coin cladistic exercise. You can make a short cladogram using
pennies, nickels, dimes and quarters based on their shared and "advanced"
1) group all the coins that are round (all of them)
2) now branch the coins that are silver and round (dimes, quarters branch
off after pennies)
3) the next branching point is for the coins that are round and silver,
but with smooth edges (nickels only)
On this cladogram, pennies represent ancestral species because they exhibit
"primitive traits". Nickels represent the most "advanced" group. A tad
simple, but to the point.
Instructor: Anthony 30 Sep 6:13 AM
Keep in mind that both Jonathan & Amar have suggested using inanimate
objects for their lessons. I usually use vehicles (bike, car, plane, space
shuttle... you can add in motorcycle to test for understanding) And these
are great ways to introduce the ideas of how to mark presence/absence of
characters, but don't forget that none of the features of candy or coins
or vehicles are derived, they are all determined by their makers. Also,
primitive means earlier, while advanced means later. As we see in the biodiversity
of our planet, many primitive traits are still allowing success. Advanced
is not necessarily "better."
Agnes 1 Oct 6:29 PM
In my biology class I actually use a cladogram when we learn about the
evolution of homo sapiens. I map out the fossils that have been found in
order to show the link between apes and humans. The kids seem to pick up
on it fairly well.
Shaunti 30 Sep 10:12 AM
I would love to try a new activity with them. Thanks! I never really taught
it because until this year, the entire course was one semester. It has
now been spit into invert for 1st semester and vert for 2nd semester. I
will be teaching the 2nd semester, so this year I should have time. I have
them list characteristics of birds and reptiles. Then I introduce a reproduction
of archeopteryx and demonstrate how its characteristics do not fit into
"traditional" Linnaean classification. It works well toward getting them
to understand the relationship between dinos and birds, but they still
don't quite accept that today's birds are really dinos. I try to get them
to classify archaeopteryx as reptile or bird, and of course it doesn't
work well for them. That is where I can introduce clasdistics.
Christina 6 Oct 10:40 AM
HI Jonathan - I have very fun activities that I just did yesterday with
my kids - sorting and recognizing differences between organisms. When I
go trekking with my older students each year, one of the things we do is
a beach litter shell count on the beaches we document. We've been doing
this since l989, so we have lots of sets and several different beaches.
When I do cladistics with my younger 9th graders, to get the kids to begin
observe different characteristics, I put a big pile of shells in the center
of each lab table and have them "sort" them by what they thick are species.
It takes them quite a while to separate them, but when they are done, some
tables have lots of species and a few of each species, some groups have
a few species and lots of examples. I then have them think of reasons why
their collections might be different. This introduces all kinds of interesting
discussion about what might be happening on the beaches. Painlessly they
figure out how to make careful observations and then begin to see why this
might be an important study. We then use this to begin the discussion of
how paleontologists don't have living animals to use, and what are the
limitations of making assumptions based on fossil remains, etc. It's very
fun. I should have taken a digital pic before they cleaned up, but just
didn't think of it.
Christina 6 Oct 11:13 AM
Ok, here's another collecting activity with a twist. I have the kids go
and collect leaves to make their own key, but to initially get them to
observe the differences, I have them make rubbings of each leaf after they
have dried in their press foe a couple of days. This focuses them on characters
like veining and leaf border and overall shape. It's also fun for them,
and fixes in the minds the idea of careful observations.