Sarah Cramer, our teacher, is back with us after an intensive week of training up in Yosemite, so this is the first time the returning and new ZAMs were all together with her and introductions were in order. Once again I was struck by the diversity and vastness of experience ZAMs bring with them to training.
Next it was on to Ecosystem Dynamics so we could see how all the information we are gathering fits together.
The Big Picture
Ecosystem Dynamics is a fancy way of saying “all life is interconnected, ” and today Sarah helped us see that with a little game: each of us was a part of the Savannah ecosystem— from a Dung Beetle to the sun and everything in between. We used one ball of yarn to show how, for example, an Eland is connected to grass (they eat it) and grass is connected to the soil which is connected to the Dung Beetle, etc. It’s all about the transfer of energy from the sun.
By the time we were done we were all woven together through our dependencies and vulnerabilities. Then, dramatically, Sarah had a few of us “disappear” from the system. What happened? You can guess: the entire Web of Life fell apart. In the real world, this is called ecosystem collapse.
Functions are Different than Food Chains
The lecture that followed was pretty intense as we discovered the difference between habitats and range, niches and trophic levels and…well, you had to be there. Let me just say that I discovered something really major about ecology that I had never thought about before: there is a difference between where an animal is on the food chain and the functional role he might play in his ecosystem.
For example, Meerkats, by digging in the soil to make tunnels, loosen the soil so seeds can take root—that is one of their functions. But, they are also part of the food chain because while they are eating, say, a scorpion, they sometimes get eaten by a snake which in turn might get eaten by a bird and so it goes: the Circle of Life.
Another concept that was new to me was that some animals play such an important role in their ecosystems that the entire system will collapse if that single species disappears. One example is the African Elephant, which knocks down trees so that the savannahs, which support untold thousands of life forms, can survive. Without them, trees would take over and all the animals adapted to grassland living would suddenly find themselves homeless.
It all gets back to consequences and how we really have to understand ecosystem dynamics before we go trotting off into a rainforest and start cutting down trees for our hardwood floors. Ask the Easter Islanders about this! (Oh, I forgot…cutting down all their trees led to their own extinction.)
You can learn more about Keystone species here: http://en.wikipedia.org/wiki/Keystone_species
Out to the Zoo
After an hour in the classroom we were all ready to go out to the African Village so experienced docents could show us how to “interpret” the animals to the public. They used skulls and drawings and physical props to help children and adults see how the animals are unique and what we need to do to protect them and their cousins here.
I must be a geek because I really enjoy the taxonomy lectures: it is so interesting to see how animals can be grouped by features we don’t even think about. And some of these groupings make for strange bedfellows.
For example, members of the Order Carnivora, which includes Lions, Meerkats and Hyenas, have whiskers, binocular color vision, 4-5 toes on each foot, a raised bone on the skull to anchor their powerful jaws (called a “sagital crest”), and scissorlike molars (called “carnassial teeth”).
Not all members of the class Carnivora are carnivores, however. Pandas only eat plants, but since they meet all the criterion of Carnivora, that’s where they get placed.
Vision is Destiny
The last subject today was comparing the vision of animals who have eyes that face forward (like Lions and Monkeys) to those whose eyes are on the side of their heads (like Horses and Zebra). It can all be summed up in this little ditty:
The reason is that the side-facing eyes of a cow have a blind spot in front of their noses so it would be pretty hard for them to keep their eyes on prey long enough to stalk and catch it, but they have a wide field of vision for keeping track of their herd, and finding grasses and branches to nibble as they amble along the plains. Here’s a sketch that illustrates the two types of vision:
Forward-facing eyes like ours, have binocular vision which gives us great depth perception, but less peripheral vision, so these animals are all about what’s out front.
All this is to prepare us for Wednesday when our Keepers will discuss the Hoofstock on our African Veldt.