biology units 1 and 2 prentice hall biology
Terms
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- Science
- organized way of using evidence to learn about the natural world; also, the body of knowledge that scientists have built up after yearsof using this process
- Hypothesis
- possible explanation for a set of observatioins or possible answer to a scientific question
- Inference
- logical interpretation based on prior knowledge and experience
- Data
- evidence; information gathered from observations
- Observation
- use of one or more of the senses--sight, hearing, touch, smell, and sometimes taste--to gather information
- Theory
- well-tested explanation that unifies a broad range of observations
- Responding Variable
- factor in an experiment that a scientist wants to observe, which may change in response to the manipulated variable; also known as a dependent variable
- Manipulated Variable
- factor in an experiment that a scientist purposely changes; also known as independent variable
- Controlled Experiment
- a test of the effect of a single variable by changing it while keeping all other variablse the same
- Spontaneous Generation
- hypothesis (disproven) stating that life could arise from nonliving matter
- Biology
- science that seeks to understand the living world
- Cell
- collection of living matter enclosed by a barrier that separates the cell from its surroundings; basic unit of all forms of life
- Sexual Reproduction
- process by which cells from two different parents unite to produce the first cell of a new life form
- Asexual Reproduction
- Process by which a single parent reproduces by itself
- Metabolism
- set of chemical reactions through which an organism build up or breaks down materials as it carries out its life processes
- Stimulus
- a signal to which an organism responds
- Homeostasis
- process by which organisms maintain a relatively stable internal environment
- Evolution
- change in a kind of organism over time; process by which modern organisms have descended from ancient organisms
- Metric System
- decimal system of measurement based on certain physical standards and scaled on multiples of 10
- Microscope
- device that produces magnified images of structures that are too small to see with the unaided eye
- Compound Light Microscope
- microscope that allows light to pass through a specimen and uses two lenses to form an image
- Electron Microscope
- microscope that forms an image by focusing beams of electrons onto a specimen
- Cell Culture
- group of cells grown in a nutrient solution from a single origional cell
- Cell Fractionation
- technique in which cells are broken into pieces and the different cell parts are separated
- Ecology
- scientific study of interactions among organisms and between organisms and their environment
- Biosphere
- part of Earth in which life exists including land, water, and air or atmosphere
- Species
- group of similar organisms that can breed and produce fertile offspring
- Population
- group of individuals of the same species that live in the same area
- Community
- assemblage of different populations that live together in a defined area
- Ecosystem
- collection of all organisms that live in a particular place, together with their nonliving environment
- Biome
- group of ecosystem that have the same climate and dominant communities
- Autotroph
- organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer
- Producer
- organism that can capture energy from sunlight or chemicals and use it to produce food from inorganic compounds; also called an autotroph
- Photosynthesis
- process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches
- Chemosynthesis
- process by which some organisms, such as bacteria, use chemical energy to produce carbohydrates
- Heterotroph
- organism that obtains energy from the foods it consumes; also called a consumer
- Consumer
- organism that relies on other organisms for its energy and food supply; also called a heterothroph
- Herbivore
- organism that obtains energy by eating only plants
- Carnivore
- organism that obtains energy by eating animals
- Omnivore
- organism that obtains energy by eating both plants and animals
- Detritivore
- organism that feeds on plant and animal remains and other dead matter
- Decomposer
- organism that breaks down and obtains energy from dead organic matter
- Food Chain
- series of steps in an ecosystem in which organisms transfer energy by eating and being eaten
- Food Web
- newtork of complex interactions formed by the feeding relationships among the carious organisms in an ecosystem
- Trophic Level
- step in a food chain or food web
- Ecological Pyramid
- diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web
- Biomass
- total amount of living tissue within a given trophic level
- Biogeochemical Cycle
- process in which elements, chemical compunds, and other forms of matter are passed from one organism to another and from one part of the poisphere to another
- Evaporation
- process by which water changes from a liquid into an atmospheric gas
- Transpiration
- loss of water from a plant through its leaves
- Nutrient
- chemical substance that an organism requires to live
- Nitrogen Fixation
- process of converting nitrogen into ammonia
- Denitrification
- conversion of nitrates into nitrogen gas
- Primary Productivity
- rate at which organic matter is created by producers in an ecosystem
- Limitin Nutrient
- single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem
- Algal Bloom
- an immediate increase in the amount of algae and other producers that results from a large input of a limiting nutrient
- Weather
- condition of Earth's atmosphere at a particular time and place
- Climate
- average, yearr-after-year conditions of temperature and precipitation in a particular region
- Greenhouse Effect
- natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases
- Polar Zone
- cold climate zone where the sun's rays strike Earth at a very low angle
- Temperate Zone
- moderate climate zone between the polar zones and the tropics
- Tropical Zone
- warm climate zone that receives direct or nearly direct sunlight year round
- Biotic Factor
- biological influence on organisms within an ecosystem
- Abiotic Factor
- physical, or nonliving, factor that shapes an ecosystem
- Habitat
- the area where an organism lives, including the biotic and abiotic factors that affect it
- Niche
- full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions
- Resource
- any necessity of life, such as water, nutrients, light, food, or space
- Competitive Exclusion Principle
- ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time
- Predation
- interaction in which one organism captures and feeds on another organism
- Sybiosis
- relatioinship in which two species live closely together
- Mutualism
- symbiotic relationship in which both species benefit from the relationship (+, +)
- Commensalism
- symbiotic relationship in which one member of the association benefits and the other is neither helped nor harmed (+, =)
- Parasitism
- sybiotic relationship in which one organism lives in or on another organism (the host) and consequently harms it (+, -)
- Ecological Succession
- gradual change in living communities that follows a disturbance
- Primary Succession
- succession that occurs on surfaces where no soil exists
- Pioneer Species
- first species to population an area during primary succession
- Secondary Succession
- succession following a disturbance that destroys a community without destroying the soil
- Tolerance
- oranism's capacity to grow or thrive when subjected to an unfavorable environmental factor
- Microclimate
- climate with a small area that differs significantly from the climate of the surrounding area
- Canopy
- dense covering formed by the leafy tops of tall rain forest trees
- Understory
- layer in a rain forest formed by shorter trees and vines
- Deciduous
- term used to refer to a tree that sheds its leaves during a particular season each year
- Coniferous
- term used to refer to trees that produce seed-bearing cones and have thin leaves shaped like needles
- Humus
- material formed from decauing leaves and other organic matter
- Taiga
- biome in which the winters are cold but summers are mild enough to allow the ground to thaw
- Permafrost
- layer of permanently frozen subsoil in the tundra
- Plankton
- tiny, free-floating organisms that occur in aquatic eenvironments
- Phytoplankton
- population of algae and other small, photosynthetic organisms found near the surface of the ocean and forming part of plankton
- Zooplankton
- tiny animals that form part of the plankton
- Wetland
- ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the year
- Estuary
- wetlands formed where rivers meet the ocean
- Detritus
- particles of organic material that provide food for organisms at the base of an estuary's food web
- Salt Marsh
- temperate-zone estuary dominated by salt-tolerant grasses above the low-tide line by seagrasses underwater
- Mangrove Swamp
- coastal wetland dominated by mangroves, salt-tolerant woody plants
- Photic Zone
- well-lit upper layer of the oceans
- Aphotic Zone
- permanently dark layer of the oceans below the photic zone
- Zonation
- prominent horizontal bonding of organisms that live in a particular habitat
- Coastal Zone
- marine zone that extends from the low-tide mark to the end of the continental shelf
- Kelp Forest
- coastal ocean community named for its dominant organism--kelp, a giant brown algae
- Coral Reef
- diverse and productive environtment named for the coral animals that make up its primary structure
- Benthos
- organisms that live attached to or near the ocean floor
- Population Density
- number of individuals per unit of area
- Immigration
- movement of individuals into an area occupied by an existing population
- Emigration
- movement of individuals out of an area
- Exponential Growth
- growth pattern in which the individuals in a population reproduce at a constant rate
- Logistic Growth
- growth pattern in which a population's growth rate slows or stops following a period of exponential growth
- Carrying Capacity
- largest number of individuals of a population that a given environment can support
- Limiting Factor
- factor that causes the growth of a population to decrease
- Density-Dependent Limiting Factor
- limiting factor that depends on population size
- Predator-Prey Relationship
- mechanism of population control in which a population is regulated by predation
- Density-Independent Limiting Factor
- limiting factor that affects all populations in similar ways, regardless of population size
- Demography
- scientific study of human populations
- Demographic transition
- change in a population from high birth and death rates to low birth and death rates
- Age-Structure Diagram
- graph of the numbers of males and females within different age groups of a population