Transcript predator and prey relationships

Predator and Prey Relationships
Definition of predator review:
• 1) We are also predators when we hunt, fish,
or buy meat or vegetables from the grocery
store.
• 2) Not all predators are carnivores- also
herbivores and carnivorous plants
• 3) Not all prey die as a result of predation
(ex: salamanders’ tails & starfish
regeneration.)
How do predators increase
their chances of getting a meal?
• Herbivores- simply walk, swim, or fly up
to their plant prey.
• Carnivores- feed on mobile prey so have 2
options:
– Pursuit: generally fast paced.
– Ambush: generally slow paced.
The thrill of pursuit….
• Cheetah- catch prey by being able to run
very fast.
• American bald eagle- fly and have keen
eyesight.
• Wolves and African lions- cooperate by
hunting in packs.
• Humans- invented tools (weapons & traps)
to capture prey.
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The patience of ambush….
• A stationary frog ambushes flying insects by flicking out
its long, sticky tongue.
• Spiders and praying mantises sit in flowers that match
their color and ambush visiting insects.
• A lion’s coloring allows it to blend in with savanna grass
so it can get closer to its prey.
• The alligator snapping turtle lies camouflaged in a streambottom and dangles its worm-shaped tongue to entice fish
into its powerful jaws.
• Drops of sticky digestive fluid which look like pollen hang
from the tentacles of a carnivorous sundew plant.
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How do prey defend themselves
against predators?
• Prey species have evolved various protective
mechanisms, otherwise they would easily be
captured and eaten.
• Some can run, swim, or fly fast; some live in large
groups; others have highly developed sight or a
sense of smell that alerts them to the presence of a
predator.
• Others have a protective shell, thick bark, spines,
thorns, camouflage, use chemical warfare,
warning coloration, mimicry or behavioral
strategies.
Warning coloration on a poison dart frog sends a
signal to experienced predators not to eat its
poisonous flesh (skin oozes one of the strongest
poisons known.)
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The viceroy butterfly (right) gains
protection by looking like the poisonous
monarch butterfly (left).
Protective shells
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Most mollusks
Armadillos
Crabs
Turtles
Corals
Exoskeletons
Spines, thorns, & thick bark
• Spines in porcupines
• Thorns in cacti and rosebushes
• Some insect species have evolved shapes
that look like twigs (stick caterpillars),
thorns (treehoppers), dead leaves, or bird
droppings on leaves.
Chemical Warfare!
• Some prey species discourage predators with
chemicals that are poisonous (oleander plants),
irritating (bombardier beetles), foul smelling
(skunks, skunk cabbages, stink bugs), or bad
tasting (buttercups and monarch butterflies).
• To date, scientists have identified over 10,000
defensive chemicals made by plants including
cocaine, nicotine, caffeine, cyanide, opium,
strychnine, peyote and rotenone (insecticide).
When a bombardier beetle is assaulted by an
ant, it defends itself by spewing out a boiling
hot irritant from special glands.
When touched, the snake caterpillar alters its
body shape to look like the head of a snake
and “strikes” at whatever touches it.
Senses of Prey
• Left-brained versus right-brained animals?
• Predators are primarily left-brained, or
responding, animals. This means they take
time, access information and somewhat
figure things out.
• Prey animals are instinctively right-brained,
or reacting animals. This means they run
from all new situations until they can get the
situation categorized as a real danger or a
non-danger.
Average senses versus
keen senses?
• Predators have keen senses, but prey
animals must have extremely keen
senses to forewarn them of danger
before the danger gets within striking
distance.
Predator/Prey Evolution
• Galapagos tortoises eat the branches of the cactus
plants that grow on the Galapagos Islands.
• On one of the islands, where long-necked tortoises
live, the branches are higher off the ground.
• On another island, where short-necked tortoises
live, the branches are lower down.
• The cactuses, the prey, may have evolved high
branches so that the tortoises, the predators, can't
reach them.
Can Animals Sense Natural
Disasters?
• Animals have keen senses that help them avoid
predators or locate prey.
• Senses might also help them detect pending
disasters.
• There are two theories as to how animals may be
able to detect earthquakes.
– One theory is that animals sense the earth's vibrations.
– Another is that they can detect changes in the air or
gases released by the earth.
• Scientists- what would they think?
• There has been no conclusive evidence as to how
animals may be able to sense earthquakes.
• Some researchers believe the animals at Yala
National Park were able to detect the earthquake
and move to higher ground before the tsunami hit,
causing massive waves and flooding.
• Researchers around the world are continuing to
study animal behavior and earthquakes.
• It is hoped that these studies will help to aid
earthquake predictions.