Special Relationships
Unit 1 – Animal Geography
Habitat –vs- Niche
• Habitat
– The location in which
the organism lives
(grasslands, freshwater,
tree tops, inside a host,
etc.)
• Niche
– The lifestyle of the
organism within the
habitat (predator,
nocturnal, parasite,
scavenger, etc.).
Competition occurs naturally between living organisms which coexist in
the same environment. For example, animals compete over water supplies,
food, and mates. In addition, humans compete for attention, wealth,
prestige, and fame.
Example – black tipped reef sharks feeding
In ecology, predation describes a biological interaction where a predator
organism feeds on another living organism or organisms known as prey.
Example – lizardfish feeding on shrimp gobies
The term symbiosis commonly describes close and often
long-term interactions between different biological species.
-mutualism
-commensalism
-parasitism
The term Mutualism describes any relationship between
individuals of different species where both individuals derive
a fitness benefit.
Example: The ants eat the plant while the pollen is transferred to another
plant on the ants back.
Commensalism describes a relationship between two living
organisms where one benefits and the other is not
significantly harmed or helped.
Example: A frog using a lily pad to sit on and wait for prey does not harm
the plant.
A parasitic relationship is one in which one member of the association
benefits while the other is harmed. Parasitic symbioses take many forms,
from endoparasites that live within the host's body, to ectoparasites that
live on its surface. In addition, parasites may be necrotrophic, which is to
say they kill their host, or biotrophic, meaning they rely on their host
surviving.
Example – leech is a parasite (ectoparasite)