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71 terms

Chapter 15 and 16 Unit 2 Biology

The meanings and terms of the words used in these two chapters
STUDY
PLAY
Abundance
the property of a more than adequate quantity or supply
Acceleration phase
Stage of population growth indicated by the start of the upward-turning section of a curve denoting population growth.
Birth Rate
the ratio of live births in an area to the population of that area
Carrying Capacity
largest number of individuals of a population that a environment can support
Closed populations
only births & deaths affect population size. eg. laboratory, zoos, etc...
Cohort
a group people having approximately the same age
Community
(ecology) a group of interdependent organisms inhabiting the same region and interacting with each other
Death Rate
the ratio of deaths in an area to the population of that area
Deceleration Phase
Stage of population growth indicated by the flattening out of an S-shaped curve as the carrying capacity is reached.
Density
the amount per unit size
Density Dependent
Referring to any characteristic that varies according to an increase in population density.
Density Independent
Referring to any characteristic that is not affected by population density.
Distribution
the act of distributing or spreading or apportioning
Environmental Resistance
All the limiting factors that tend to reduce population growth rates and set the maximum allowable population size or carrying capacity of an ecosystem
Exponential Growth
Growth at a constant rate of increase per unit of time; can be expressed as a constant fraction or exponent
J-Shaped Curve
Curve with a shape similar to that of the letter J; can represent prolonged exponential growth. See exponential growth.
K-Selected
organisms that reproduce later in life, produce fewer offspring and devote significant time and energy to the nurturing of their offspring
Lag Phase
A short period of time **prior to exponential growth of a bacterial population during which no, or very limited, cell division occurs.
Logistic Growth
growth pattern in which a population's growth rate slows or stops following a period of exponential growth
Mark - Recapture
capturing and marking organisms, then recapturing them and counting how many are marked
Migration Rate
Rate of immigration into and emigration out of a given population.
Open Populations
Have no barriers to dispersal and the larvae can travel over large geographic distances. Populations can exchange larvae through connectivity.
Population
the act of populating (causing to live in a place)
Population Dynamics
The study of how complex interactions between biotic and abiotic factors influence variations in population size.
Quadrats
Mark off a particular area (quadrat) and count the number of individuals of a species in that area. Repeat in another area. Average the results to estimate the population density of that species within the larger area. The more quadrats used, the better the estimate.
R-Selected
term denoting a species with high biotic potential whose members produce a large number of offspring in a relatively short time but do not care for their young after birth
S-Shaped Curve
Leveling off of an exponential, J-shaped curve when a rapidly growing population exceeds the carrying capacity of its environment and ceases to grow.
Sampling
measurement at regular intervals of the amplitude of a varying waveform (in order to convert it to digital form)
Species Richness
the number of different species in a community
Total Count
a test sample which determines the total number of that cell type per unit volume of blood
Transects
Line through an area. regular intervals along line using quadrat. Used where enviroment changes gradually
True Census
A total count of all members of a species in a given population. Also called a total count.
Zero Population Growth
A decline of the total fertility rate to the point where the natural increase rate equals zero.
Alien Species
species that do not naturally occur within an area and that have usually arrived in the area as a result of human intervention (whether deliberate or accidental)
Biocontrol
Use of one kind of organism that is a predator or parasite of a pest species in order to reduce or eliminate populations of the pest.
Biopesticides
What are certain types of pesticides that are derived from natural materials such as plants animals, bacteria, and certain minerals?
Biosphere
the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist
Biota
all the plant and animal life of a particular region
Bushfires
a fire burning out of control in a rural area
Classical Biocontrol
Biocontrol method using natural predators to reduce or eliminate populations of exotic species.
Climax Community
a relatively stable long-lasting community reached in a successional series; usually determined by climax and soil type
Conservation
the preservation and careful management of the environment and of natural resources
Conservation Biocontrol
protecting the natural enemies already present.
Dryland Salinity
Increased salt levels in soil resulting from exessive tree clearing and subsequent rising of the water table.
Epicormic Buds
Dormant buds found under the bark of some trees. The buds will grow when the leafy crown of the tree is destroyed.
Estuary
the wide part of a river where it nears the sea
Eutrophication
process by which a body of water becomes too rich in dissolved nutrients, leading to plant growth that depletes oxygen
Exotic Species
organisms that are not native to a particular area
Hydrosphere
the watery layer of the earth's surface
Immuno-contraception
Experimental procedure for blocking conception in an exotic species by causing females to produce an immune response against her own eggs.
Invasive
relating to a technique in which the body is entered by puncture or incision
Irrigation Salinity
the major source of salts on irrigated land is salts in the irrigation water
Lignotubers
bud that lies under the bark of stem or root of a plant, they are able to sprout after damage to the plant
Lithosphere
the solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle
Noxious
injurious to physical or mental health
Obligate Seeder
A type of plant that is killed in a bushfire, but whose seeds survive and germinate after that fire.
Over-Harvesting
Commercial harvesting that removes too many breeding individuals from a population such that the rate of remoal exceeds the rate of natural replacement.
Ozone Layer
a layer in the stratosphere (at approximately 20 miles) that contains a concentration of ozone sufficient to block most ultraviolet radiation from the sun
Pioneer Species
first species to populate an area during primary succession
Primary Succession
succession that occurs on surfaces where no soil exists
Regulated Flow
Flow of water in rivers where that flow is impeded by dams.
Remote Sensing
The acquisition of data about Earth's surface from a satellite orbiting the planet or other long-distance methods.
Rhizomes
underground stems that anchor a fern and absorb water
Salinity
the taste experience when salt is taken into the mouth
Salt Interception
Scheme for removal of salt through pumping saline groundwater from below ground and storing it.
Sclerophyll
a plant with thick leathery leaves
Secondary Succession
succession on a site where an existing community has been disrupted
Succession
(ecology) the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established
Unregulated Flow
Describes the flow of water in rivers with no artificial structures present, Such as dams or weirs
Vegetative Reproducers
Plants that after a bushfire, regenerate through structures such as underground stems and epicormic buds.
Wildfire
a raging and rapidly spreading conflagration