Chapter 4 Flashcards
The Ecology of Communities
Competition
when organisms seek the same resource; negative interaction
Intraspecific competition
competition between members of the same species
Interspecific competition
competition between members of different species
Resource partitioning
individuals use shared resources in different ways
Predation
process by which individuals of one species kill and eat individuals of another
Parasitism
organism depends on another for nourishment, usually not resulting in death
Pathogens
parasites that cause disease, including protists, bacteria, and viruses
Coevolution
parasites and hosts adapt/counter-adapt to each other
Evolutionary arms race
duel of escalating adaptations between parasites and hosts
Herbivory
animals feed on plant tissue (e.g. insects)
Mutualism
two or more species benefit each other
Symbiosis
close physical association between species
Pollination
relationships which require free-living organisms to encounter each other once
Community
assemblage of populations of organisms living in the same area at the same time
Trophic level
rank in the feeding hierarchy
Producers/autotrophs
use photosynthesis/chemosynthesis to make their own sugars
Primary consumers
consume producers
Secondary consumers
consume primary consumers
Tertiary consumers
consume secondary consumers
Detritivores
scavenge waste/dead bodies
Decomposers
break down nonliving matter into smaller molecules, cycling nutrients back into the soil
Biomass
collective mass of living matter in a place and time
Food webs
all interlinking food chains in a community, showing the map of energy flow
Keystone species
species with an impact far out of proportion to its abundance (e.g. decomposers recycle nutrients/replenish soil)
Top predator
control populations of lower trophic level consumers (often keystone species)
Ecosystem engineer
species that physically alters its ecosystem (e.g. beavers and prairie dogs, who are often keystone species)
Trophic cascade
top predators are lost and primary consumers overconsume producers, causing an ecological disturbance
Disturbance
event with rapid/drastic effects on the community and ecosystem (e.g. tree falls, hurricane, prairie fire, insect outbreaks)
Resistance
community that resists change and remains stable
Resilience
community that is changed by disturbances but returns to its original state
Succession
when severe disturbances eliminate all or most species in a community
Pioneer species
one that colonizes during succession, usually with spores/seeds that travel long distances
Climax community
species that takes over pioneers
Primary succession
disturbance removes all plant soil life
Secondary succession
disturbance alters the community, leaving soil life intact (e.g. farming, fires, storms, landslides)
Regime shift
entire character of a community changes due to a disturbance
Novel communities/no-analog communities
human disturbance mixes species that have not previously occurred on Earth
Introduced species
people bring non-native arrivals to a community
Invasive species
introduced species that thrive
Restoration ecology
study of ways to restore altered areas to their pre-industrialization condition
Ecological restoration
restore ecosystem functionality, return community to its pre-settlement condition
Biome
regional complex of similar communities, classified primarily by dominant plant life, which is the result of climate
Climate diagram/climatograph
depict seasonal changes to temperature/precipitation, helping tell the story of the biome
Deciduous forests
mid-latitude forests with relatively even precipitation throughout the year (frozen in winter)
Temperate grasslands
prairies/steppes; temperature differences are extreme between winter and summer, rainfall diminishes
Temperate rainforests
mid-latitude forests rich in rainfall, mostly containing coniferous trees (contain fertile soil, which is vulnerable to erosion if forests are cleared)
Tropical rainforests
diverse tree species at low densities with acidic soils low in organic matter that have lush vegetation, dark, damp interiors, and diverse communities
Tropical dry forests
wet and dry seasons that each occupy about half the year, with consistently warm temperature and leaves that are shed during the dry season
Savannas
tropical grassland interspersed with acacias, found in dry tropical areas with distinct wet and dry seasons
Deserts
driest biome, with less than 25 cm of rain per year - soils have high mineral/low organic matter content; animals must adapt to dry environment
Tundras
cold, dry biomes where underground soil is frozen; most directly impacted by climate change and pollution, though humans do not live there
Permafrost
underground soil is permanently frozen
Boreal forests/taiga
cold with precipitation, dominated by few species of evergreen trees, with acidic, nutrient-poor soil
Chaparral
covered by dense thicket of evergreen shrubs, with mild/wet winters and warm/dry summers and frequent fires; climate is introduced by nearby oceans
