Bi 210 Exam Vocab

Abiotic

Physical or nonliving environment

Adaptation

A physiological, morphological, or behavioral trait with an underlying genetic basis that enhances the survival and reproduction of its bearers in their environment

Biosphere

The highest level of biological organization, consisting of all living organisms on Earth plus the environments in which they live

Biotic

living components of an environment

Climate Change

Directional change in climate over a period of three decades or longer

Community

a group interacting species that occur together at the same place and time

Consumer

an organism that obtains its energy by eating other organisms or their remains

Controlled Experiment

a standard scientific approach in which an experimental group is compared with a control group

Ecology

The scientific study of interactions between organisms and their environment

Environmental Science

an interdisciplinary field of study that incorporates concepts from the natural sciences and the social sciences focused on how people affect the environment and how we can address environmental problems

Evolution

Descent with modification

Hypothesis

a possible answer to a question developed using previous knowledge or intuition

Landscape

an area that is spatially heterogeneous in one or more features of the environment, such as the number or arrangement of different habitat types

Natural Selection

the process by which individuals with certain heritable characteristics tend to survive and reproduce more successfully than other individuals because of those characteristics

Net Primary Production

the amount of energy per unit of time that producers capture by photosynthesis and chemosynthesis, minus the amount they use in cellular respiration

Nutrient Cycle

The cyclic movement of nutrients between organisms and the physical environment

Population

a group of individuals of the same species that live within a particular area and interact with one another

Producer

an organism that can produce its own food by photosynthesis or chemosynthesis

Replication

the performance of each treatment of a controlled experiment, including the control, more than once

Scale

the spatial or temporal dimension at which ecological observations are collected

Scientific Method

an iterative and self-correcting process by which scientists learn about the natural world

Alternative Stable State

different community development scenarios, or community states, that are possible at the same location under similar environmental conditions

Climax Stage

the last stage of succession that is thought to be stable until disturbances or stresses shift the community back to earlier successional stages

Disturbance

an abiotic event that kills or damages some individuals and thereby creates opportunities for other individuals to grow and reproduce

Hysteresis

the inability of a community that has undergone change to shift back to the original community type, even when the original conditions are restored

Pioneer Stage

the first stage of primary succession

Primary Succession

succession that involves the colonization of habitats devoid of life

Secondary Succession

succession that involves the reestablishment of a community in which some, but not all, of the organisms have been destroyed

Stability

when a community retains, or returns to, its original structure and function after some perturbation

Succession

the process of change in the species composition of a community over time as a result of abiotic and biotic agents of change

Biotic Resistance

interactions of the native species in a community with non-native species that exclude or slow the growth of those non-native species

Community Function

the set of processes that shape community structure, including primary production, atmospheric gas exchange, or resistance to disturbance

Competitive Displacement

a process in which best competitor uses limiting resources that the weaker competitor requires ultimately causing a decline in the weaker competitors population to the point of extinction

Complementary Hypothesis

a hypothesis proposing that as the species richness of a community increases, there is a linear increase in the positive effects of those species on community

Dynamic Equilibrium Model

an elaboration of the intermediate disturbance hypothesis proposing that species diversity is maximized when the level of disturbance and the rate of competitive displacement are roughly equivalent

Idiosyncratic Hypothesis

a hypothesis proposing that as species richness of a community increases, community function will vary idiosyncratically as the result of some species having stronger effects on the community than others

Intermediate Disturbance Hypothesis

a hypothesis proposing that species diversity in communities should be great at intermediate levels of disturbance because competitive exclusion at low levels of disturbance and mortality at high levels of disturbance should reduce species diversity

Lottery Model

a hypothesis proposing that species diversity in communities is maintained by a “lottery” in which resources made available by the effects of disturbance, stress, or predation are captured at random by recruits from a larger pool of potential colonists

Redundancy Hypothesis

a hypothesis that assumes an upper limit on the positive effected species richness on community function because one species richness reaches some threshold, the function of species in the community will overlap

Resource Partitioning

the use of limiting resources by different species in a community in different ways

Resource Ratio Hypothesis

a hypothesis proposing the species can coexist in a community by using the same resources, but in differing proportions

Biodiversity

the diversity of important ecological entities that span multiple spatial scales, from gene to species to communities

Community Structure

the set of characteristics that shape a community, including the number, composition, and abundance of species

Competitive Network

sets of competitive interactions involving multiple species in which every species negatively interacts with every species, thus promoting species coexistence

Direct Interaction

an interaction that occurs between two species, such as predation, competition, or a positive interaction

Ecosystem Engineer

a species that influences its community by creating, modifying, or maintaining physical habitat for itself and other species

Food Web

a diagram showing the connections between organisms and the food they consume

Foundation Species

a species that has large, community-wide effects on the habitat or food of other species by virtue of its size or abundance

Functional Group

a subset of a community that includes species that function in similar ways, but do not necessarily use the same resources

Guild

a subset of a community that includes species that use the same resources, whether or not they are taxonomically related

Horizontal Interactions

non-trophic interactions, such as competition and some positive interactions, that occur within a trophic level

Indirect Interactions

an interaction in which the relationship between two species is mediated by a third (or more) species

Interaction Strength

a measure of the effect of one species (the interactor) on the abundance of another species (the target species)

Interaction Web

a concept that describes both the trophic and non-trophic interactions among the species in a traditional food web

Keystone Species

a strong interactor species that has an effect on energy flow and community structure that is disproportionate to its small size, abundance, or biomass

Rank Abundance Curve

a graph that plots the proportional abundance of each species in a community relative to the others in rank order, from most abundant to least abundant

Redundant Species

having the same function in a community as other species in that community within a larger functional group

Shannon Index

the index most commonly used to describe species diversity quantitatively

Species Accumulation Curve

a graph that plots species richness as a function of the total number of individuals that are present with each additional sample

Species Composition

the identity of the species present in a community

Species Diversity

a measure that combines the number of species in a community and their relative abundances compared with one another

Species Evenness

the relative abundances of different species compared to one another in a community

Species Richness

the number of species in a community

Trophic Cascade

a change in the rate of consumption at one trophic level that results in a series of changes in species abundance or composition at lower trophic levels

Trophic Facilitation

an interaction in which a consumer is indirectly facilitated by a positive interaction between its prey or food plant and another species

Trophic Level

a group of species that obtain energy in similar ways, classified by the number of feeding steps by which group is removed from primary producers, which are the first trophic level

Acclimatization

an organisms adjustment of its physiology, morphology, or behavior to lessen the effect of an environmental change and minimize the associated stress

Avoidance

a response to stressful environmental conditions that lessens their effect through some behavior or physiological activity that minimizes an organisms exposure to the stress

Autotroph

an organism that converts energy from sunlight or from inorganic chemical compounds into chemical energy

Boundary Layer

a zone close to a surface where a flow of fluid, usually air, encounters resistance and becomes turbulent

Climate Envelope

the range of climate variables, including temperature, humidity, precipitation, and solar radiation, that are associated with a species geographic distribution

C3

a biochemical pathway involving the uptake of CO2 by the enzyme ribulose 1,5 bisphosphate carboxylase/oxygenase and synthesis sugars by the Calvin Cycle

C4

a biochemical pathway involving the daytime uptake of CO2 by the enzyme phosphoenol pyruvate carboxylase in mesophyll cells

Crassulacean Acid Metabolism (CAM)

a photosynthetic pathway in which CO2 is fixed and stored as an organic acid at night, then released to the Calvin Cycle during the day

Chemosynthesis

the use of energy from inorganic chemical compounds to fix CO2 and produce carbohydrates using the Calvin Cycle

Dormancy

a state in which little or no metabolic activity occurs

Detritus

freshly dead or partially decomposed remains of organisms

Ecotype

a population with adaptations to unique local environmental conditions

Ectotherm

an animal that regulates its body temperature primarily through energy exchange with its external environment

Endotherm

an animal that regulates its body temperature primarily through internal metabolic heat generation

Fixation

the uptake of the gaseous form of a compound

Hibernation

torpor lasting several weeks during the winter

Heterotroph

an organism that obtains energy by consuming energy rich organic compounds made by other organisms

Resistance

any force that impedes the movement of compounds such as water or gases such as carbon dioxide along an energy or concentration gradient

Photorespiration

a chemical reaction in photosynthetic organisms in which the enzyme rubisco takes up O2, leading to the breakdown of sugars, the release of CO2, and a net loss of energy

Photosynthesis

a process that uses sunlight to provide the energy needed to take up CO2 and synthesize sugars

Stomate

a pore in plant tissues, usually leaves, surrounded by specialized guard cells that control its opening and closing

Stress

an abiotic factor that results in a decrease in the rate of an important physiological process, for an organisms growth, reproductions, or survival

Torpor

a state of dormancy in which endotherms drop their lower critical temperature and associated metabolic rate

Tolerance

the ability to survive stressful environmental conditions

Pubescence

the presence of hairs on the surface of an organism

Gravitational Potential

the energy associated with gravity

Lower Critical Temperature

the environmental temperature at which the heat loss of an endotherm triggers an increase in metabolic heat generation

Matric Potential

the energy associated with attractive forces on the surfaces of large molecules inside cells or on the surfaces of soil particles

Osmotic Adjustment

an acclimatization response to changing water availability or salinity n terrestrial and aquatic environments that involves changing the solute concentration, and thus the osmotic potential, of the cell

Osmotic Potential

the energy associated with dissolved solutes

Physiological Ecology

the study of the interactions between organisms and the physical environment that influence their survival and persistence

Pressure Potential

the energy associated with the exertion of pressure

Thermoneutral Zone

the range of environmental temperatures over which endotherms maintain a constant basal metabolic rate

Turgor Pressure

pressure that develops in a plant cell when water moves into it, following a gradient in water potential