Unit B Flashcards
Definition of Ecology?
the study of interactions between organisms and their living and non-living environment
Definition of Abiotic Factor?
a non-living factor that influences an organism
Definition of Biotic Factor?
a living factor that influences an organism
Definition of Ecotone?
a transition area between ecosystems
Definition of Ecological Niche?
an organism’s role in an ecosystem, consisting of its place in the food web, its habitat, its breeding area, and the time of day at which it is most active
Definition of Biome?
a large geographical region with a specific range of temperatures and precipitation, and the organisms that are adapted to those conditions of temperature and precipitation
Definition of Permafrost?
permanently frozen soil
Definition of Muskeg?
soil above the permafrost that is swampy or boggy in summer
Definiton of Understorey?
below the canopy layer; usually shrubs and smaller trees
Definition of Littoral Zone?
the area from the shore of a lake or pond to the point where no more plants grow in the lake bottom
Definition of Limnetic Zone?
the area of a lake or pond in which there is open water and sufficient light for photosynthesis to occur
Definition of Plankton?
autotrophic and heterotrophic microorganisms found in the limnetic zone of a lake or pond
Definition of Profundal Zone?
the region of a lake beneath the limnetic zone, in which there is insufficient light for photosynthesis to occur
Definition of Groundwater?
water in the soil or rock below Earth’s surface
Definition of Epilimnion?
the upper level of a lake, which warms up in summer
Definition of Hypolimnion?
the upper level of a lake, which warms up in summer
Definition of Thermocline?
the zone between the epilimnion and hypolimnion, in which temperature changes rapidly
Definition of Biotic Potential?
the maximum number of offspring that a species could produce with unlimited resources
Definition of Carrying Capacity?
the maximum number of individuals of a species that can be supported by an ecosystem
Definition of Law of the Minimum?
states that the nutrient in the least supply is the one that limits growth
Definition of Law of Tolerance?
states that an organism can survive within a particular range of an abiotic factor
Definition of Density-Independent Factor?
a factor in an ecosystem that affects members of a population regardless of population density
Definition of Density-Dependent Factor?
a factor in an ecosystem that affects members of a population because of the population density
Definition of Slash-and-Burn?
the complete clearing of a forest by felling and burning the trees
Definition of Clear-Cutting?
the removal of all trees in an area
Definition of Selective Cutting?
the harvesting of only certain trees from an area
Definition of Prescribed Burn?
burn a controlled fire set intentionally in a designated area
Definition of Oligotrophic?
having low nutrient levels
Definition of Eutrophic?
having high nutrient levels
Definition of Coliform Bacteria?
a type of bacteria that occurs naturally in the intestines of humans and other animals, and indicates the presence of fecal contamination in water
Definition of Biological Oxygen Demand (BOD)
the amount of dissolved oxygen needed by decomposers to completely break down the organic matter in a water sample at 20 °C over five days
Definiton of Watershed?
the land that drains toward a lake or other body of water
Definition of Taxonomy?
the science of classification according to the inferred (presumed) relationships among organisms
Definition of Binomial nomenclature?
a method of naming organisms by using two names—the genus name and the species name. Scientific names are italicized.
Definition of Genus?
the first part of a binomial name; a genus includes several species
Definition of Species?
a group of organisms that look alike and can interbreed under natural conditions to produce fertile offspring
Definition of Taxa?
categories used to classify organisms
Definiton of Protista?
a kingdom originally proposed for all unicellular organisms such as the amoeba. More recently, multicellular algae have been added to the kingdom.
Definition of Monera?
in a five-kingdom system, a kingdom that includes organisms that lack a true nucleus
Definiton of Archaebacteria?
in a six-kingdom system, a kingdom consisting of prokaryotic microorganisms distinct from eubacteria that possess a cell wall not containing peptidoglycan and that live in harsh environments such as salt lakes and thermal vents
Definition of Eubacteria?
in a six-kingdom system, a kingdom consisting of prokaryotic microorganisms that possess a peptidoglycan cell wall
Definition of Phylogeny?
the history of the evolution of a species or a group of organisms
Definition of Dichotomous Key?
a two-part key used to identify living things.
Definition of Paleontology?
the study of fossils
Definition of Radiometric Dating?
a technique used to determine the age of a rock or fossil
Definition of Biogeography?
the study of the geographic distribution of life on Earth
Definiton of Endemic?
a term used to describe a species that is found in one location only
Definition of Homologous Features?
features with similar structures but different functions
Definition of Analogous Features?
features that are similar in appearance and function, but do not appear to have the same evolutionary origin
Definiton of Vestigial Features?
rudimentary structures with no useful function
Definition of DNA?
the molecule that makes up genetic material
Definition of Gene?
a segment of DNA that performs a specific function, such as coding for a particular protein
Definition of Artificial Selection?
the process of humans selecting and breeding individuals with the desired traits
Definiti9on of Spontaneous Generation?
the belief that living things arose from non-living matter
Definition of Inheritance of Aquired Characteristics?
the false concept of inheritance of features acquired during the life of an individual
Definition of Natural Selection?
the result of differential reproductive success of individuals caused by variations in their inherited characteristics.
Definition of Mutation?
a change in the DNA sequence in a chromosome
Definition of Neutral Mutation?
a mutation that has no effect on the organism
Definition of Fitness?
an organism’s reproductive success
Definition of Harmful Mutation?
a mutation that reduces an organism’s fitness
Definition of Beneficial Mutation?
a mutation that enhances an organism’s fitness
Definition of Asexual Reproduction?
the production of offspring from a single parent; offspring inherit the genes of that parent only
Definition of Siblings?
offspring from the same parent (in asexual reproduction) or parents (in sexual reproduction)
Definition of Sexual Reproduction?
the production of offspring by the union of sex cells from two different parents; the offspring inherit a combination of genes from both parents
Definition of Gene Pool?
all the genes in a certain population
Definition of Speciation?
the formation of new species
Definition of Allopatric Speciation?
speciation by reproductive isolation
Definition of Theory of Gradualism?
the idea that speciation takes place slowly
Definiton of Theory of Punctuated Equilibrium?
the idea that species evolve rapidly, followed by a period of little or no change
Definiton of Divergent Evolution?
evolution into many different species
