Transcript symbiotic_3 (new window)

Unit Four:
I Depend on You
What is Symbiosis?
• Any close relationship among species.
• Not all relationships among organisms involve
food; many organisms can live together and
share resources in other ways.
• In order for a relationship to be symbiotic,
there must be two organisms that can be
identified.
• There are various forms of symbiosis,
including: mutualism, commensalism, and
parasitism.
What is mutualism?
• A symbiotic relationship in which both
species benefit.
• Example: Fungi & Algal (found in lichens)
What is
commensalism?
• A symbiotic relationship in which one
organism benefits and the other is not
affected.
• Example: Remoras & Sharks
What is parasitism?
• A symbiotic relationship in which one
organism benefits but the other is
harmed.
• Example: Dogs & Roundworms
Now, it’s time to….
Burdocks and Passing
Vertebrates
• Burdocks are common weeds found along
roadsides and fields. The seed heads (burs)
of burdocks are long spines with hooked tips.
The hooked tips catch onto the hair of
passing vertebrates (cows, deer, dogs,
humans) and are carried elsewhere until they
finally fall off or are pulled off by the
carriers.
Burdocks and Passing
Vertebrates
Monarch Butterfly and
Milkweed Plants
• The Monarch butterfly feeds on species of milkweeds.
The milkweeds contain a group of chemicals called
cardiac glycosides. Cardiac glycosides are poisonous to
vertebrates (although not to invertebrates). The
butterflies store these cardiac glycosides. If a bird (or
other vertebrate such as a mouse or frog) eats a
Monarch it finds them distasteful and is later sick.
Experimentally vertebrate learn to avoid Monarchs
butterflies.
Monarch Butterfly and Milkweed
Plant
Cattle Egret and Cattle
• The Cattle Egret resides in pastures and
fields among livestock such as cattle and
horses, feeding on the insects stirred up by
the movement of the grazing animals. The
egrets benefit from the arrangement, but the
livestock, generally, do not.
Cattle Egret and Cattle
Mistletoe and
Surrounding Trees
• The mistletoe develops high up on the
branches of other trees. It develops root-like
structures from its stem which penetrate the
surrounding trees and take water from the
water-carrying vessels. A mistletoe plant can
be easily identified in winter because it
remains green when the leaves of its host
have fallen to the ground.
Mistletoe and Surrounding Trees
Mushroom and Tree
• A mushroom is made up of fungus. The fungus
aids the tree in absorbing water from the
soil, increases the stability of the root
system, and protects the roots from drying
out. In return, the tree provides sugars and
starches to the fungus that the fungus uses
in its metabolism.
Mushroom and Tree
Pseudo-Scorpions and
Beetles
• Pseudo-scorpions are scorpion-like animals. They have
pinchers like scorpions, but lack a sting. A few species
of pseudo-scorpions hide by concealing themselves
under the wings of large beetles. The pseudo-scorpion
gains the advantage of being hidden over wide areas
while simultaneously being protected from predators.
The beetle is, presumably, unaffected by the
presence of the hitchhikers.
Psuedo-Scorpions and Beetles
Now that we have the
basics about symbiosis,
it’s time to put our
knowledge to work!