Ecology Exam 2 Flashcards
How does competition affect biodiversity?
Limiting the number of species that can be packed into a given niche
Intraspecific competition
Competition within the species for food, mates, etc.
interspecific competition
Competition between members of different species
Exploitation competition
limited food or space
mutual interference
direct aggression, toxic waste products
Apparent competition
increase in common predator or parasite population
Guild
a group of species that exploit a common resource base in similar fashion
Fundamental niche
a species niche in the absence of competition, conditions where it can survive and reproduce
Realized niche
A species niche with competition
Avoiding competition
Avoid character displacement, on either behavioral or ecological time scale
Character displacement
when two species inhibit the same environment
Keystone predation
predation increases biodiversity if it removes species that would otherwise competitively exclude other species
Keystone species
a single or (few) species within a community who’s presence or absence affects the community
Dominant species
species that have a high population density, biomass density within a community.
Low disturbance rate
The competitively dominant species takes over and excludes other species
High disturbance rate
Everyone gets clobbered, rarely any species survive.
Mechanisms behind biodiversity
Evolutionary process
ecological process
Ecological process
competition
predation
spatial patchiness + disturbance
colonization + extinction
Similarities of habitat patches and islands
small units of land separated by similar units of barrier.
Differences of habitat patches and islands
How much of a barrier does the intervening land represent?
- Isolated from what? Where is the ‘source’ population?
- Time
- how long has the patch been isolated
Habitat islands
Areas that are not true islands, but can be considered for island biogeography therom
-Mountain
-caves
Species area curve
number of species on patch or island increases as space increases
Island biogeography
species diversity on islands as a dynamic balance between colonizations and extinctions
Habitat fragmentation
The process of fracturing a formerly continuous island landscape into smaller and often isolated pieces.
Possible effects of habitat fragmentation
Isolation, road mortality, and edge effects
Edge effect
the noticeable changes in population or community structure that occur at the boundary between two different habitats
higher diversity
undisturbed nucleus
high biodiversity, large gene pools
Risk of extinction concerns
spatial uncertainty
In discrete habitat patches
Landscape approach
landscape
modeling- spatially explicit models
Landscape
A mosaic of habitat patches across which organisms move, settle, reproduce, and eventually die.
usually heterogenous
Modeling - spatially explicit models must
Incorporate habitat heterogeneity and patchy distributions
-Depict landscape structure and population demography
What determines community structure
individualistic, holistic, and intermediate hypothesis
individualistic hypothesis
change assemblage
abiotic factors
communities lack discrete geographical boundaries
Holistic hypothesis
assemblage of linked species,
biotic interactions,
discrete communities with distinct boundaries
intermediate hypothesis
aspects of holistic and individualistic
population is a unit of evolution*
many species affect each other’s evolution*
manifests as community properties
Ecosystem hypothesis
land use patterns
resource management
conservation of biology
habitat fragmentation
preserve design
