An Australian tick species secretes
a toxin (holocyclotoxin) in its saliva when it feeds on dogs, livestock and
humans. This toxin inhibits the release of the neurotransmitter acetylcholine
into the synapse.
A
rancher bought 10 calves in Australia, where these ticks are common and occur
in large numbers, and shipped them to an island off the continent where she
had a station (ranch). Unfortunately for the cattle and her, 50 Australian ticks
rode over on the cattle and established a population on the island.
Some plants develop flowers that
are pollinated by flies. Such flowers are simple red flowers, have little
odor, and provide easy access to nectar (sugar) that attracts flies. The flies
recognize the flowers by their red color and the sugar by sensors in their
feet. They draw up the liquid nectar using their special sucking mouthparts.
While foraging for the nectar, the flies transfer pollen from one plant to
another.
In the Kisatchie National Forest
in north-central Louisiana researchers have been trying to determine the characteristics
associated with bat day-roosts (resting places) that are located under bridges.
One hypothesis concerning day-roost choice by bats concerns thermoregulation.
The researchers predicted that in warmer months, bats should choose the coolest
possible locations on the undersurface of the bridge and during colder months
the bats should choose the warmest possible locations on the undersurface
of the bridge.
Lake
Victoria in Africa was originally a flowing river that was transformed into
a lake about a million years ago. Today there are at least 4 genera and over
200 species of African cichlid fishes. It is thought that the African cichlid
fish in Lake Victoria are descendants of a small subpopulation of a single species
of cichlid that inhabited the rivers in the Lake Victoria basin. The ancestral
cichlids probably fed on insects. Today, there are species of cichlids in Lake
Victoria that eat one of the following: algae, plankton, other fish species,
mollusks, insects, fish scales or only fish eyes.
In
the Rocky Mountains, crossbill birds live and eat lodgepole pine seeds. In many
areas, red squirrels are an important predator of the pine seeds. Crossbill
birds can live in these same places and also eat pine seeds, but the squirrels
get to the seeds first, so those birds don’t get as many seeds. However,
in a few isolated places, there are no red squirrels, and crossbill birds are
the most important seed predator for lodgepoles. Scientists from the University
of California at Berkeley are interested in the ecology of the lodgepole pine’s
habitat and the squirrels and crossbill birds. They examine areas where the
predominant predator is the squirrel and other areas where the predominant predator
is the crossbill birds. They determine what proportions of heavy and light pinecones
are found in each area. They find either heavy pinecones with fewer seeds or
lighter pinecones with more seeds. The results of their studies are graphed
below.
A man was killed when he was hit across the face by a blunt object in a grocery
store. Traces of the murder weapon are stuck to the victim's face. Two witnesses
to the crime agree that the murder weapon was a food item, whose wrapper burst
open when it struck the man's face. However, one witness says it was a large
package of frozen broccoli and the other insists that it was a large piece of
frozen pork. When the detective examines the traces of the weapon under the
microscope, he sees the following structures in the cells: nucleus, cell wall,
ribosomes, mitochondria, cell membrane.
Tired
of studying? If you are because you have REALLY spent a lot of time studying,
then you might want to spend some time with this incredible time wasting halloween
diversion that one of my Honors students sent me.
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