IB Biology Review
About this set
Created by:
Gondwana on May 7, 2008
Subjects:
Description:
Review of all IB Biology subjects.
Classes:
Biology Seniors 2012, OSHS IB English Seniors '12
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84 terms
Terms | Definitions |
|---|---|
 ecology | the study of relationships between living organisms and between organisms and their environment |
| ecosystem | a system made up of organisms as well as the abiotic factors in the area |
| population | a group of organisms of the same species who live in the same area at the same time |
| community | a group of populations living and interacting with each other in an area |
| species | a group of organisms which can interbreed and produce fertile offspring |
| habitat | the environment in which a species normally lives or the location of a living organism |
| autotrophs | producers; they can make their own food |
| heterotrophs | consumers; they feed on ready made organic material |
| detritivores | organisms that feed on the detritus and decomposing organic material of living organisms |
| saprotrophs | decomposers; organisms that feed on dead organisms and products of living organisms |
| carrying capacity | the maximum number of organisms of a species, or the maximum population size which an environment is able to support |
| random sample | a sample where every individual in a population has an equal chance of being chosen |
| trophic level | Position in the food chain, determined by the number of energy-transfer steps to that level; a functional classification of taxa within a community that is based on feeding relationships |
| standard deviation | used to summarize the spread of values around the mean; ∑((X-X)²/n-1) |
| species | a group of organisms with similar characteristics, which can interbreed and produce fertile offspring |
| protoctista | unicellular and multicellular eukaryotic organisms; may be auto or heterotrophic and live in salt and fresh water |
| fungi | eukaryotic and feed by absorption of nutrients; cell walls are made of chitin |
| plantae | eukaryotic photosynthetic organisms; cell wall contains cellulose and cells contain chlorophyll |
| animalia | feed by ingestion |
| evolution | change in a gene pool of a species over a period of time |
| half-life | the number of years it takes for 50% of a sample to decay |
| organelle | a discrete structure within a cell, and has a specific function |
| magnification | measure size of diagram ÷ actual size of object |
| tissue | an integrated group of cells that share structure and are adapted to perform a similar function |
| organ | a combination of two or more tissues which function as an integrated unit, performing one or more specific functions |
| organ system | a group of organs that specialize in a certain function together |
| diffusion | movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient |
| osmosis | passive movement of water molecules from a region of lower solute concentration to a region of higher solute concentration across a semi permeable membrane |
| organic | molecules containing carbon that are found in living systems (Not CO2); often have covalent bonds |
| enzyme | a globular protein that accelerates a specific reaction; catalysts that can be used over and over |
| active site | the region of an enzyme surface that binds to the substrate during the reaction catalyzed by the enzyme |
| denaturation | a structural change in a protein that results in a loss of its biological properties |
| degenerate | more than one codon can code for a single amino acid |
| universal | codes are the same for all living organisms |
| recombination | the reassortment of genes into different combinations from the parents |
| gene | a heritable factor that controls a specific characteristic consisting of a length of DNA occupying a specific position on a chromosome called a locus |
| allele | a specific form of a gene, usually differing from other alleles by one or a few bases only and occupying the same locus as other alleles of the gene |
| genome | the total genetic material of an organelle, organism, or cell |
| gene pool | the total of all genes carried by the individuals in a population |
| gene mutation | a change in the base sequence of a gene |
| genotype | the alleles possessed by an organism |
| phenotype | the characteristics of an organism |
| dominant allele | an allele which as the same effect on the pheno type whether it is in a homozygous or heterozygous state |
| recessive allele | an allele which has an effect on the phenotype in the homozygous state |
| codominant alleles | alleles which have a partial effect in the heterozygous state but a more pronounced effect in the homozygous state |
| locus | the position of a gene on the chromosome |
| homozygous | having two copies of an allele |
| heterozygous | having different alleles of a gene |
| carrier | an individual that has a recessive allele that does not have an effect on the phenotype |
| test cross | testing a suspected heterozygote by crossing it with a known recessive homozygote |
| sex linkage | genes carried on the sex chromosomes, usually the X |
| linkage group | a group of genes whose loci are on the same chromosome |
| polygenic inheritance | the inheritance of a characteristic which is controlled by more than one gene |
| genetic screening | testing individuals in a population for the presence of a gene (or a certain allele of a gene) |
| clone | a group of organisms of identical genotype or a group of cells descended from a single parent cell |
| cell respiration | the controlled release of energy in the form of ATP from organic compounds in cells |
| pathogens | organisms that cause disease |
| active immunity | immunity due to production of antibodies by the organism itself after infection |
| passive immunity | immunity due to acquisition of antibodies from another source (can be injected by needle or passed through placenta or breast milk) |
| natural immunity | immunity due to infection |
| artificial immunity | immunity due to a vaccine |
| resting potential | electrical impulse across a cell membrane when not propagating an impulse |
| action potential | the localized reversal and then restoration of electrical potential between the inside and outside of a neuron as the impulse passes along it |
| innate behavior | behavior that normally occurs in all members of a species despite natural variation in environmental influences |
| taxis | locomotion in a particular direction in response to an external stimulus |
| kinesis | movement in an organism where the rate depends on the stimulus |
| classical conditioning | modification of behavior in an animal as a result of the detection of correlations between external events |
| operant conditioning | a learning procedure in which a reinforcement follows a particular response |
| imprinting | an attachment to an object encountered during a short period after birth, usually a parent |
| food chain | a linear and simple feeding relation, where one organism has one type of food and is eaten by one type of organism |
| food web | more complex than a food chain and it includes a larger variety of organisms, Each of which feed on a variety of other organisms and they are in turn fed on by more organisms |
| greenhouse effect | a NATURAL PHENOMENON that was required for life to form on the planet |
| energy flow (in a food chain) | energy losses between trophic levels include material not consumed or material not assimilated and heat loss through cell respiration |
| population size factors | if (natality + immigration) > (mortality + emigration) then a population is increasing |
| exponential phase | occurs when there are no controlling factors |
| transitional phase | the birthrate begins to decrease |
| plateau phase | occur as carrying capacity is reached |
| density dependent factors | more effect in crowded populations (predation and disease) |
| density independent factors | independent of population size (weather, natural disasters) |
| extrinsic population-regulating mechanisms | originate outside the population (food supply, natural enemies, disease, weather) |
| intrinsic population-regulating mechanisms | seen in the physiology or behavior (less offspring in crowded populations, mass migration) |
| kingdoms | prokaryotae, protoctista, fungi, plantae and animalia |
| prokaryotes | unicellular organisms lacking a nucleus and other membrane-bound organelles; circular DNA |
| Taxa hierarchy | kingdom, phylum, class, order, family, genus and species |
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