Chapter 52 Flashcards
Interaction types among species in a community
- Commensalism: when one species benefits but the other species in unaffected
- Competition: when individuals use the same resources - results in lower fitness for both
- Consumption: when one organism eats or absorbs nutrients from another - increases consumer’s fitness but decreasing the victim’s fitness
- Mutualism: when two species interact in a way the congers fitness benefits to both
Intraspecific competition
density-dependent competition
interspecific competition
when members of different species use the same limiting resources
-can be divided into direct and indirect
niche
a range of resources and conditions that species deals with
-overlap in niches leads to competition
Fundamental niche
the total theoretical range of environmental conditions that a species can tolerate
Realized Niche
the portion of the fundamental niche that a species actually occupies, given limiting factors - competition with other species
Fitness trade-offs in competion
Ability to compete trades off with ability to withstand other factors
Niche differentiation
natural selection selects against individuals that compete
Herbivory
the consumption of plant or algal tissues by herbivores
Predation
the killing and consumption of most or all of another individual by a predator
Endoparasites
Live inside a host’s body and are usually simple and wormlike
Ectoparasites
live outside of hosts and typically have adaptations for harvesting fluids from host
Parasitoids
free living as adults but have endoparasitic larvae - usually fatal to hosts
Constitutive or Standing defenses
defenses that are always present
-cryptic coloration and object resemblance
-Escape behaviour
-toxins and other chemicals
-schooling flocking
-defense armor and weapons
Mimicry
the close resemblance of one species to another
-Batesian Mimicry: when nontoxic prey species resemble dangerous prey species. One species benefits
-Mullerian mimicry: when two harmful prey species resemble each other - Both benefit
Inducible defenses
traits produced in response to the presence of a predator
-less costly but take time - chemical, physical, behavioral
Attributes of community structure
- The total number of species
- the general types and outcomes of interactions among all species
- the relative abundance of those species
- they physical aspects that matter
Bottom-up influences on a food web
from plants/algae up the food chain
Top down influences on a food web
primary by predators down the food chain
Ecosystem engineers in food web
make habitats for other animals in web
Trophic cascade
when impacts in a food web propagate down the web
Disturbance
any strong, short-lived disruption to a community that changes the distribution of living or nonliving resources
What factors is a disturbances impact a function of
- type of disturbance
- frequency of disturbance
- severity of disturbance
Primary Succession
organisms colonize bare mineral soil
secondary succession
the soil is already present
-faster recovery than primary succession
Steps of secondary succession in temperate forests
- pioneering species: weedy species become established in disturbed soils
- early successional community: weedy species are replaced with longer-lived herbaceous species
- Mid-successional community: shrubs and short-lived trees begin to invade
- climax community: long-lived trees species mature
Development of communities after disturbances
early succession species:
-are short lived
-small stature
-disperse their seeds over long distances
Later species:
-long lived
-larger
-good competitors for light and nutrients
The role of species interactions in succession
- Facilitation: existing species help those that arrive
- Tolerance: existing species of not affect the arrivals
- Inhibition: presence of one species inhibits the success of another
Species richness
the number of species present in a given community
species diversity
a weighted measure that incorporates a species’ relative abundance
What factors predict species richness on islands
- the number of existing species
-immigration vs extinction - Island size
-large vs small - remoteness of the island
-nearshore vs remote
how does the size of an island effect species richness
-large island causes increased species richness
-small island causes decreased species richness
How does the remoteness of an island effect species richness
-Remote island will decrease richness
-nearshore island will increase richness
Global species richness patterns hypotheses
-high-productivity hypothesis
-area and age hypothesis
-environmental variability
