Transcript HOW DO YOU CATCH YOUR FOOD?

Studying Species Interactions
Owl Pellets
• Predator/Prey
• Food Webs
Macaroni Lab
• Competition
• Predator/Prey
Fig Newtons
• Symbiosis/mutualism
• Niches
Organisms interact with biotic & abiotic factors
Organisms shape their environment
&
the environment shapes organisms!
What happens when 2 niches overlap?
how species interact
Environmental Science 302
Problem:
2 niches overlap
WHAT IS YOUR SOLUTION?
1. Migrate
2. Change feeding habits
3. Adapt behavior
4. Suffer a sharp population decline
5. Become extinct in that area
What type of species overcome this more easily?
 Generalists
 or Specialists?
Phrased another way:
I want something that you want…
• Will we compete?
• Will I eat you?
• Will we work together
some how?
• In nature, there are 3
basic types of
interactions…
Competition
Predation
Symbiosis
Interaction
Competition
+
-
0
Predation
Mutualism
Parasitism
Commensalism
Interacting
Examples
I. Competition
INTERFERENCE
• Species A limits Species B’s
access
EXPLOITATION
• A & B have equal access but
differ in how fast or
efficiently they exploit it
• Aka: establishing a territory
• Ex: invasive species
Is there a solution to competition?
RESOURCE PARTITIONING 
dividing up scarce
resources
big prey
2 species use the same thing
– In different ways
– At different times
– In different places
small prey
What does this graph say?
II. Predation
• Predator feeds directly on all or part of a
living organism (the prey).
– The prey does not have to die
– Predation is not only about carnivores!
• Can be GOOD for prey population
because…
 drives natural selection!
– Sick, weak, & aged die, leaving resources
for the healthy
Capturing Prey
• Herbivores got it easy!
– Special digestive adaptations
• EX:
• Carnivores must hunt!
– Predator needs MOBILITY, SENSES, and ABILITY
TO HANDLE prey
• EX?
Prey Escape & Defense
• RUN!!!
• Physical Defenses
– Structure
– Crypsis
– Warning Coloration
• Chemical Defenses
• Deception
– Looks
– Behavior
• Behavioral
– Scare tactics
• Loss & Regeneration
Some cool cases of prey
adaptations
Synchlora larvae
Wavy-lined Emerald Caterpillar
Utetheisa ornatrix
Recently, while experimenting with a gaudily colored moth,
Utetheisa ornatrix, a group of us found that scales can be impregnated with
toxins. As a larva, Utetheisa feeds on leguminous plants of the genus
Crotalaria, which has long been known to contain poisonous alkaloids.
The larva is unaffected by these poisons, which it stores in its
body and retains through metamorphosis into the adult stage. Some of the
alkaloid in the adult is built into the scales, so the moth is unpalatable to
spiders. Utetheisa therefore does not need to flutter free when it lands in a
spider web; instead, it lies still and relies on the spider to cut it loose.
The strategy never fails: the moment the moth lands in the web,
the spider darts toward it, briefly inspects it, then uses its fangs to sever each
strand that imprisons the moth, setting the moth free.
HOW DO YOU
CATCH YOUR
FOOD?
Do you know what type of
relationship your Fig Newton was
involved in?
Mutualism
Life Cycle of the Fig Wasp
YUMMY!
Thank an insect for your food!
• The FDA allows 13 insect heads per 100 grams
III. Symbiosis
• “Living together” in a long-lasting relationship
3 types
Parasitism
Mutualism
Commensalism
Parasitism
1 species (PARASITE) gets nourishment by living on,
in, or near another species (HOST) over an
extended period of time
– Endoparasites
– Ectoparasites
Rarely Lethal!
Why would you kill a good thing?
Mutualism
• Both species benefit in various ways
– Having pollen dispersed for reproduction
– Being supplied with food
– Receiving protection
• Not as much cooperation as exploitation
Commensalism
• One species benefits, the other is neither
helped nor harmed
• Clownfish & Sea Anemone
– Protection
– Feed on anemone’s leftovers
Detailed fig life cycle
• The process starts when a pregnant female wasp enters a fig through a
secret hole (hidden by scales) at the top of the fig. In the process, the
wasp transfers pollen from the male flowers of the fig from which she
emerged to the “female” flowers of the new fig she entered. The wasp
also deposits her eggs in a type of “female” flower that will not set fruit.
The fruits of figs are actually nutlets formed within the fruiting structure,
called a fig. The tiny fruits impart the crunch to figs and Fig Newtons. The
deposited pollen not only enables the fruits to grow, but also becomes a
food source for the young wasps. The adult female wasp does not leave
the fig; she dies there. When the larvae mature into wasps, the wingless
males hatch and impregnate the females still developing in the flowers;
the males of many species then also die inside the fig. The young,
pregnant females, however, emerge from the flowers and exit the fig—
usually before it ripens and falls to the ground—and move on to a new
flowering fig, where the entire process begins again.