Lecture 22 Flashcards
Ecological niche
where an organism lives, AND their role in the ecosystem (producer, consumer, decomposer) AND how they interact with other organisms.
The niche is a function of the anatomy & physiology of an organism and the environment (abiotic & biotic)
Niche specialization:
The process by which a species becomes better adapted, by natural selection, to the specific characteristics of a particular habitat.
Interactions influence
The distribution of organisms &
Their abundance
Species interactions
Direct interaction Competition: for limited resources Predation: predators eat, prey are eaten Herbivory: eat autotrophs Symbiosis: Mutualism, Commensalism, Parasitism
Indirect interaction
Facilitation: One organism makes it easier for another to survive (Facilitation (-/+ or 0/+) interaction in which one species positively effects another species without direct contact)
Intraspecific and Interspecific competitions?
Intraspecific competition: Same species
Interspecific competition: Different species
If competition for a limited resource is intense, there are 2 possible outcomes:
Competitive exclusion: one species drives the other out. complete competitors can’t coexist: one will be eliminated
Niche differentiation: competing species use the environment differently in a way that helps them to coexist.
–> Ex. Resource partitioning: different species eat different food in same habitat
limited resources in animals and plants
Animals: food, water, nesting areas
Plants: sunlight exposure, space, nutrients in soil
Fundamental niche vs Realized niche
FUNdamental niche: comprises the full range of climate conditions & food resources that permits the individuals in a species to live.
In nature, however, many species do not occupy all the habitats permitted by their anatomy and physiology.
REALized niche: the actual range of habitats occupied by a species (where they actually live)
WHERE U COULD POTENTAILY LIVE VS WHERE U REALLY LIVE
Why realized niche is smaller than the fundamental niche
Usually other species: compete for available resources prey on the organisms in question influence their growth & reproduction (ex parasites) ↓ reducing the range actually occupied.
How to catch the prey
Pursuit: speed
Ambush & Camouflage
How to avoid the predator: Plants
Mechanical: Spines, thorns, thick wax to protect against herbivores
Some produce toxic chemicals
We use some of these as insecticides
Animal defense against predators
Escape
Mechanical defenses
Associate in groups: safety in numbers. Ex antelopes
Cryptic coloration: camouflage (ex. same color as tree)
Warning coloration (ex. blue or red on green leaf)
Mimicry (both look the same, may both be poisonous or not)
Chemical
Abiotic components of an ecosystem
Sunlight Temperature Moisture levels Nutrient supply Soil and water chemistry Wind levels Living space
Species diversity: 2 components?
Species richness: number of different species
Species relative abundance: how “evenly spread” are the species?
