Bio Ch 45 Flashcards
Community
assemblage of populations of different species interacting with one another in the same environment
Species richness
species composition of a community; listing of the various species found in that community
Species diversity
includes both species richness and species evenness (relative abundance of the different species)
Island Biogeography Model of Species Diversity
species diversity on an island depends on the distance from the mainland (closer islands have more diversity than islands farther away) and the total area of the island (large islands have more diversity than smaller islands)
Habitat
a particular place where a species lives and reproduces
Ecological niche
role a species plays in its community; includes the resources used to meet energy, nutrient, and survival demands
Fundamental niche
all the abiotic conditions under which a species could survive when adverse biotic conditions are absent
Realized niche
those conditions under which a species does survive when adverse biotic interactions, such as competition and predation, are present
Competitive Exclusion Principle
no two species can indefinitely occupy the same niche at the same time
Resource Partitioning
decreases competition between 2 species, leading to increased niche specialization and less niche overlap
Character Displacement
tendency for characteristics to be more divergent when populations belong to the same community than when they are isolated; often used as evidence that competition and resource partitioning have taken place
Predation
occurs when one living organism (predator) feeds on another (prey)
Camouflage
ability to blend into the background
Mimicry
occurs when one species resembles another that possesses an overt antipredator defense
Parasitism
organism (parasite) deriving nourishment from another (host); type of symbiosis in which one of the species cause some harm to the other but tends not to kill it
Symbiosis
relationship that occurs when 2 different species live together in a unique way; it may be beneficial, neutral, or detrimental to one or both species
Commensalism
symbiotic relationship between 2 species in which one species is benefited, and the other is neither benefited nor harmed
Mutualism
symbiotic relationship in which both members benefit
Coevolution
mutualistic relationships between flowers and their pollinators are examples of this; mutual evolution in which 2 species exert selective pressures on the other species
Ecological Succession
change within a community involving a series of species replacements
Pioneer species
1st species to begin secondary succession; 1st producers to inhabit a community after a disturbance
Climax Community
proposal by F.E. Clements that succession in a particular area will always lead to the same type of community
Ecosystem
populations interact with each other and with the physical environment
Autotrophs
require only inorganic nutrients and an outside energy source to produce organic nutrients for their own use and for all other members of a community
Producers
AKA autotrophs because they produce food
Heterotrophs
need a preformed source of organic nutrients as they acquire food from a different source
Consumers
AKA heterotrophs because they consume food that was generated by a producer
Herbivores
animals that graze directly on plants or algae
Carnivores
feed on other animals
Omnivores
animals that feed on both plants and animals
Detritivores
organisms that feed on detritus, which consists of decomposing particles of organic matter
Decomposers
bacteria, fungi; acquire nutrients by breaking down dead organic matter, including animal wastes
Food web
diagram that describes trophic (feeding) relationships
Food chains
diagrams that show a single path of energy flow in an ecosystem
Trophic level
level of nutrients within a food web or chain
Ecological pyramid
flow of energy with large losses between successive trophic levels
Biomass
number of organisms multiplied by the dry weight of the organic matter within one organism
Biogeochemical cycles
pathways by which chemicals circulate through ecosystems involve both living (biotic) and nonliving (geologic) components; 4 main cycles: water, carbon, phosphorus, and nitrogen
Water (hydrologic) cycle
interdependent and continuous circulation of water from the ocean, to the atmosphere, to the land, and back to the ocean
Transfer rate
amount of a substance that moves from one component of the environment to another within a specified period of time
Greenhouse gases
gases in the atmosphere such as carbon dioxide, methane, water vapor, ozone, and nitrous oxide that are involved in the greenhouse effect
Greenhouse effect
reradiation of solar heat toward the Earth, caused by the atmosphere that allows the Sun’s rays to pass through but traps the heat in the same manner as the glass of a greenhouse
Global warming
overall rise in the Earth’s ambient temperature
Climate change
recent changes in the Earth’s climate
Eutrophication
enrichment of water by inorganic nutrients used by phytoplankton; often overenrichment caused by human activities leads to excessive bacterial growth and oxygen depletion
N2 (nitrogen) fixation
occurs when nitrogen gas is converted to ammonium, a form plants can use
Nitrification
production of nitrates during the nitrogen cycle
Denitrification
conversion of nitrate back to nitrogen gas, which then enters the atmosphere
Acid deposition
occurs because nitrogen oxides (NOx) and sulfur dioxide (SO2) enter the atmosphere from the burning of fossil fuels
