Unit D: Changes in Living Systems Flashcards
Biotic Factor
A living organism in the environment.
Abiotic Factor
A physical, non-living part of the environment.
Ecosystem
All the organisms in an area as well as the abiotic factors with which they interact.
Habitat
All the biotic and biotic factors present in an area that encourage the reproduction and survival of a particular organism.
Nutrient
Any element or compound that an organism needs for metabolism, growth or other functioning.
Algae
Microscopic, photosynthetic organisms that play a vital role in marine and freshwater ecosystems.
Harmful algal bloom
A rapid growth of algae that can deplete the oxygen dissolved in the water and lock the sunlight required by other organisms in the aquatic ecosystem.
Biomass
The dry mass of all the living organisms occupying a habitat.
Ecology
The study of the interactions of living organisms with one another and with their physical environment.
Population
A group of organisms, all of the same species which interbreed and live in the same area at the same time.
Biological community
Interacting populations living in a certain area at a certain time.
Symbiosis
A long-lasting ecological relationship that benefits at least one organisms of two different species that live in close contact.
Mutualism
A symbiotic relationship in which the organism of both species benefit.
Commensalism
A form of symbiosis in which one organism benefits and the other organism is neither helped nor harmed.
Parasitism
A symbiotic relationship in which one organism called the parasite derives benefit at the expense of another organism called the host.
Competition
An interaction in which two or more organism compete for the same limited resource.
Producer
An organism that uses light energy to synthesize sugars and other organic compounds through the process of photosynthesis.
Consumer
An organisms that uses other organisms as a source of energy.
Primary consumer/ Herbivore
An organism that eats green plants algae or phytoplanktons.
Secondary consumer
An organism that eats herbivores.
Tertiary consumer
An organism that eats secondary consumers.
Carnivore
An organism that kills and eats other animals.
Omnivore
An organism that eats both plants and animals
Scavenger
A bird or animal that feeds on dead and decaying animals that it did not kill itself.
Decomposer
An organism that breaks down complex, organic molecules into simpler molecules.
Trophic Level
The division of species within an ecosystem based upon its energy source.
Food Chain
The pathway along which food is transferred from one trophic level to another.
Food Web
The interconnected feeding relationships within an ecosystem.
Transect
A straight line perpendicular to the baseline along which ecological measurements are taken.
Biogeochemical cycle
A diagram representing the movement of elements and compounds between living and nonliving components of an ecosystem.
Photosynthesis
The 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.
Cellular respiration
The process by which cells convert the chemical energy stored in sugars into energy that the cells can use.
Carbon sink
A system that removes more carbon dioxide from the atmosphere than it releases into the atmosphere.
Peat
Deep layers of mosses and plant remains unable to completely decompose due to the lack of oxygen in water-saturated soil.
Transpiration
The loss of water vapor from a plant through its leaves.
Humidity
The atmosphere’s moisture content.
Ozone
A molecule comprised of three atoms of oxygen - O3
Nitrogen Fixation
The process of converting nitrogen gas into ammonia.
Nitrifying bacteria
A type of soil bacteria that converts ammonia into nitrates and nitrites.
Nitrification
The process of converting ammonia into nitrates and nitrites.
Denitrifying bacteria
A type of soil bacteria that converts nitrates in soil into nitrogen gas releasing this gas into the atmosphere.
Denitrification
The process of converting nitrates in the soil into nitrogen gas.
Lichen
An organism formed by the symbiotic association of a fungus and a photosynthetic alga.
Endangered Species
A species that may soon no longer exist with certain regions and or may be threatened with imminent extinction.
Habitat Fragmentation
The conversion of formerly continuous habitat into patches separated by non-habitat areas.
Habitat Destruction
The permanent alteration of vital characteristics in an organism’s habitat.
Invasive species
A species that does not normally occur in an area, is introduced by human action, and then expands to become a breeding population that threatens the area’s biodiversity.
Primary succession
The process of changing -in successive stages- an environment from an area of bare rock and few species into a complex community,
Pioneer species
Simple and hardy plants that first invade or colonize barren ground and change the environment to support more complex life forms.
Humus
The organic component of soil created from the decomposed bodies of organisms.
Terra-forming
The process of transforming a planet to become more like earth.
Secondary Succession
The return in stages to a stable climax community from an area that ad its vegetation but not its soil removed.
Sustainable development
Development that meets the needs of the present without compromising the needs of future generation.
Double time
The amount of time it takes for a population to double in size.
Exponential Growth
The rapid growth in a population caused by a constant increase.
Exponential curve or J-Curve
The distinctive shape of the graph for a population that is regularly increasing and growing exponentially.
Closed population
A group of organisms that exists in a natural or artificial setting where immigration and emigration do not occur, and numbers are only affected by births and deaths.
Open population
A group of organisms that exists in a natural setting where births, deaths, immigration and emigration affect the population numbers.
Carrying Capacity
The maximum number of individuals that can be sustained for an indefinite period in a given ecosystem.
S-curve
The distinctive shape of the graph for a population limited by factors such as disease, competition and famine.
Generation
A single step in the line of descent- grandmother, mother and daughter represent three generation.
Morphology
The detailed shape and form of an animal
Fossil record
The record of all life on Earth as preserved by all fossils that exist, whether dug up or still in the ground.
Gradualism
The theory that changes to the organism in a population occur slowly and steadily over Earth’s history.
Punctuated equilibrium
The theory that changes to the organism in a population can occur in rapid spurts followed by long periods of little change.
Gene
The basic unit of inheritance passed from parent to offspring.
Mutation
A change in a genetic instruction.
Variation
A difference in the frequency of genes and traits among individual organisms within a population.
Adaptation
Any structural trait or behavioral trait that improves an organism’s success at surviving and reproduction in a particular environment.
Asexual reproduction
The production of identical offspring from a single parent cell by budding, by the division of a single cell or by the division of the entire organisms into two or more parts.
Darwinian Fitness
The reproductive success of an organism.
Theory of evolution
A theory stating that the nature of a population gradually changes form over time.
Theory of natural selection
A theory stating that evolution takes place because more organisms are produced than can survive and that only organisms best suited to their environment survive to reproduce and, in turn, pass on their advantageous traits to their offspring.
