How Predators and Adaptations Affect the Evolution of a Species:
Before delving into any thought, definitions to remove any confusion are under way.
SPECIES: A group of similar organisms that can mate and produce fertile offspring.
PREDATOR: An animal that naturally preys on others.
ADAPTATION: A trait which helps an organism survive and reproduce.
To put it simply, a species naturally wants to live long enough to reproduce, and predators want to eat them to do the same thing. As the predator's natural instinct to survive directly conflicts with its prey's, sooner or later the prey would be extinct due to too many of its own species being devoured by the ever growing population of the predators, who have a great food source apparently - the prey. Take the katydid, for example;
Tettigoniidae Scudderia (Katydid)
The katydid is a species that has lasted millions of years and is currently 6400 species strong. However, its predators (lizards, birds, reptilians and amphibians in general) found them as quite the popular choice of food. Over generations, the katydids reproduced, being eaten, some surviving, and so forth. However, one day a mutation within the katydids population made them that much more harder to find. Those with this mutation had a better chance of surviving and so could reproduce and pass on their mutation. Over the course of millions of years, mutations in regards to mimicry meant that lizards, birds, amphibians, etc. couldn't see these katydids (now named "Leaf Katydids") and thus the species continued on.
Predators have kept up with the katydids, as now monkeys (for example) just look for moving leaves, which must have been a real kick to millions of years of evolution.
Another example of adaptations affecting evolution based on the same concept is the one we found in class. Dr. G placed pink bits and green bits of papers resembling insects in the grapevines outside the classroom and asked us all one by one to find them all. This is a chart of my results.
As one might note, the amount of pink insects found is greater than the amount of green ones, as the green ones were the same shade of green as the leaves. Similar results were found with other classmates, most finding on average 10 pink papers and 4 green papers.
A good metaphor for the Theory for Evolution is Fashion. Everyone must live with the times, know what's "in" and what's "out", and if you can't keep up, you're finished. In the katydid's case, It sort of got mixed up in the fashion of the 80's version of today's SWAG fad. Isn't Evolution great?
