Biology: UNIT B - Chapter 4-5 Terms - Bio 20 Alberta

Biotic factor

Living factors that influences an organism

Abiotic Factor

Non-living factors that influence an organism

Carrying Capacity

Maximum number of individuals in a species that can be supported by an ecosystem

Ecology

The branch of biology that deals with the relations of organisms to one another and to their physical surroundings

Groundwater

Water held underground

Law of Tolerance

An organism can survive within a particular range of an abiotic factor

Muskeg

a North American swamp or bog consisting of a mixture of water, partly dead vegetation, and permafrost

Plankton

the small and microscopic organisms drifting or floating in the sea or freshwater, consisting chiefly of diatoms, protozoans, and small crustaceans

Topsoil

Consists of minerals and humus, and is nutrient rich

Artificial ecosystem

Ecosystems planned or maintained by humans

Biotic potential

Maximum number of offspring a species can produce with optimal (or unlimited) resources

BOD

Biological Oxygen Demand

Amount of dissolved oxygen needed by decomposers to break down organic matter in a water sample

Density Dependent

Limiting factors that affect the population of a species due to the density (size) of the species

Density Independent

Limiting factors that affect the population of a species regardless of the density (size) of the species

Ecological Niche

An organisms role in an ecosystem

Ecotone

Transition areas between ecosystems

Epilimnion

Upper level of a lake, where water increases in temperature as the environmental temperature increases

Hypolimnion

Lower level of a lake, where water remains at a constant average of 4^o Celsius all year

Eutrophic (Lake)

Lake with high nutrient levels, high BOD, and high sediment build-up

Humus

Decomposed plant and animal matter, rich in nutrients

Limnetic Zone

Area where there is open water and enough light for photosynthesis to occur.

Littoral Zone

Area extending from shore to where plants no longer grow on the lake bottom

Profundal Zone

Region beneath limnetic zone where there isn’t enough light for photosynthesis

Natural Ecosystem

Ecosystems not managed by humans

Understorey

Layer of vegetation underneath the canopy in a forest

Bedrock

Rocky bottom layer of soil

Litter

Uppermost layer of soil, mostly decaying plant matter

Oligotrophic

A lake with low nutrient levels, low BOD, and less sediment

Subsoil

Level of soil with less humus and larger rocks, in between the Topsoil and the Bedrock

Biome

Large geographical area with a specific regional climate

Law of the Minimum

The nutrient in the least supply that limits population growth

Permafrost

A thick subsurface layer of soil that remains frozen throughout the year

Thermocline

Zone between Epilimnion and Hypolimnion which experiences rapid temperature changes associated with changing seasonal temperature

Acquired Characteristics

An acquired characteristic is a non-heritable change in a function or structure of a living organism caused due to an environmental change

Artificial Selection

Selective breeding; when humans choose two organisms with desirable characteristics and breed them together to get offspring that also have these characteristics

Divergent Evolution

When species share a common ancestor, but diverged to create a new species

Gene Pool

The stock/number of different genes within a population

Monera

A kingdom of organisms that include Archaea and Eubacteria

Phylogeny

The history of evolution of living organisms, or the connection and timeline of species evolution

Speciation

The process by which new species form, it occurs when groups in a species become reproductively isolated and diverge

Allopatric Speciation

Speciation by geographic isolation that results in reproductive isolation or physical separation between groups

Binomial Nomenclature

Naming rules developed by Carl Linnaeus which assigns each organism a two-part name using latin words

DNA

Hereditary material that determines which characteristics are passed onto the next generation

Genus

First part of binomial name, second most specific level of taxonomic organization

Mutation

Random change in DNA sequences due to environmental factors. Either Harmful, Neutral, or Beneficial

Protista

Eukaryotic organisms that live in aquatic or moist habitats, can reproduce sexually or asexually, some are heterotrophs and others are autotrophs. Usually algae and protozoa

Genetic Drift

The change in frequency of an existing gene variation in the population due to random chance

Analogous Features

Feature that have similar structure and function but different origin; evolved similarly but separately

Convergent Evolution

Organisms that aren't closely related evolve similar features or behaviours, often as solutions to the same problem

Eubacteria

Prokaryotic organisms, either heterotrophs or autotrophs, reproduce asexually, can live almost everywhere (bacteria, cyanobacteria)

Gradualism

Idea that speciation takes place slowly, that there was a continuous rate of evolution (believed up until mid 1900s)

Natural Selection

Organisms that are most adapted or best suited to their environment are likely to survive and pass on their traits to successive generations

Punctuated Equilibrium

Proposed in 1972 that species evolve rapidly, followed by periods of little to no change; speciation events occur in “bursts”

Taxonomy

The science of naming and classifying things, according to presumed relations between species

Archaebacteria

Prokaryotic organisms, heterotrophs, (methanogens, extreme thermophiles, extreme halophiles)

Dichotomous Key

Used to identify and classify organisms; constructed by a series of two choices, where each choice leads to a new branch on the “tree”

Gene

The basic unit of heredity passed from parent to child; genes are made up of sequences of DNA

Homologous Features

Features that have similar structure but different function

Neutral Mutation

Mutation that has no overall effect on an organism’s fitness

Species

Second part of a binomial name, most specific level of organization in taxonomy

Vestigial Features

Rudimentary structures in an organism or species that serve no useful function; a structure retained from when it used to be useful