Biol 314
Terms
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- Parasite
- Consumes the tissues or body fluids of its host
- Endoparasite
- parasite that lives inside its host
- Ectoparasite
- Parasite that lives on the outer body surface of its host
- What is a parasitic life style so extremely common?
- Because parasites are specialized for only one type of survival.
- Advantages to endoparasitism
- Well protected from natural predators
- Advantages to ectoparasitism
- Easy dispersal of offspring
- Disadvantages to ectoparasitism
- More exposed to natural enemies
- Encapsulation
- Immune response - host covers parasite or parasite eggs with capsules that kill them
- Coevolution
- The evolution of two interacting species, each in response to selection imposed by the other
- Cause of downfall of American chestnut
- fungal pathogen
- Threshold Density
- When population goes above threshold, disease susceptibility increases
- Mutualism
- +/+
- Commensalism
- +/0
- Mycorrhizae - What role do they play in communities?
- Fungi on roots - fungi get carbohydrates from the roots, and the plants benefit because it enhances water uptake
- Obligate
- Identity of species does matter - flower and moth with long tongue
- "Nurse plant" phenomenon
- Types of plants that germinate under other plants
- Why might positive interactions be more common in stressful environments?
- Less competition
- Trophic mutualism
- A mutualist receives energy or nutrients from its partner
- Habitat mutualism
- one partner provides the other with a shelter
- Service mutualism
- interactions in which one partner performs an ecological service for the other
- Beltian bodies
- modified leaflet tips which are high in protein and fat - queen ants feed her larvae with nectar from these bodies
- Community
- groups of interacting species that occur together at the same place and time
- Guild
- Things that share the same resource
- Functional group
- Things that feed in a similar way
- Richness
- number of species in a community
- Diversity
- Combined species richness and evenness (evenness = abundance)
- Rank abundance curve
-
Drastic curve - temperate forest
Leveled off curve - tropical rainforest - Accumulation Curves
- Sloped line is more diverse that the curve
- Trophic cascade
- change in the rate of consumption, results in a series of changes in species abundance at lower trophic levels
- Direct interactions
- occur between two species
- Indirect interactions
- occur when the relationship between two species is mediated by a third species
- foundation species
- species that has large, community-wide effects by virtue of its size or abundance
- ecosystem engineers
- dominant species that influences its community by creating a physical habitat for itself and other species
- "Context Dependency"
- species interactions can change under different environmental conditions - aphids and ants
- Primary succession
- colonization of habitats that are devoid of life
- Secondary succession
- the reestablishment of a community in which most organisms have been destroyed
- Climax
- a stable end point that experiences little change
- Facilitation model
- early species modify the environment in ways that benefit later species
- Tolerance Model
- early species modify the environment in neutral ways
- Inhibition Model
- early species modify the environment in negative ways
- What is meant by the idea that the tropics are both a cradle and a museum for species diversity?
-
cradle - majority of extant taxa originated there
museum - if extinction rates are low, species that diversify there will tend to stay there - Resource ratio hypothesis
- species coexist by using resources in different proportions
- nonequilibrium theories
- disturbance, stess, and predation can mediate resource availability thus affecting species interactions and coexistence
- intermediate disturbance hypothesis
- species diversity should be highest at intermediate levels of disturbance
- lottery model
- resources in a community made available by disturbance are captured at random by recruits from a larger pool of potential colonists
- Gross primary production
- total amount of carbon fixed by autotrophs in an ecosystem
- Net primary production
- GPP - respiration
- 3 factors that might affect the number of trophic levels in an ecosystem
-
disturbance
dispersal
enery - nitrification
- converts ammonia to nitrate under aerobic conditions
- denitrification
- converts nitrate to nitrogen gas and nitrous oxide under anoxic conditions
- nutrient cycle
- nutrients undergo biological, chemical, and physical transformations as they are taken up by organisms and released through decomposition, ultimately returning to their original inorganic form over time
- nutrient spiral in aquatic ecosystems
- nutrients in rivers and streams are cycled repeatedly as the water flows downstream
- Why is conservation biology called a value-based discipline?
- The science is not free of human values, and it inevitably takes place within a larger social context
- "Background extinction rate"
- estimate extinction rates from fossil records
- "taxonomic homogenization"
- areas of the world are becoming more similar due to invasive species
- population viability analysis
- counting approach to see future status of populations in a particular species
- flagship species
- charismatic species look to be saved by the public
- umbrella species
- species that people too to save because it will protect other species
- landscape ecology
- a sub-discipline of ecology that emphasizes the causes and consequences of spatial variation across a range of scales
- edge effects
- the diverse biotic and abiotic changes that are associated with such a boundary