Unit 4 AOS 2 Key Terms Flashcards
Define amino acid sequence
The primary structure of a protein; comprises the order the order of the 20 possible amino acids in the polypeptide, sometimes referred to as ‘polypeptide sequence’
Define antibiotic resistance
The capacity for a microbe to withstand the lethal effects of an antibiotic to which it was once suspectible
Define antibiotic resistance gene
A gene that codes for an antibiotic resistant genotype
Define antigenic drift
A change in the antigen of a virus that would otherwise be recognisable by the adaptive immune system, resulting from the gradual accumulation of mutation in the virus
Define antigenic shift
A sudden change in the antigen of a virus resulting from the rearrangement of genetic material from two or more strains or subtypes of the virus
Define artificial selection
Breeding of plants and animals over successive generations to produce traits that are desirable to humans; also known as ‘selective breeding’
Define beneficial mutation
A mutation that increases the organism’s chance of survival and reproduction
Define block mutation
A mutation involving rearrangements of chromosomal segments
Define bottleneck effect
When a catastrophic event or a period of adverse conditions drastically reduces the size of a population and its genetic diversity
Define broad spectrum
Describes and antibiotic (or insecticide) that is effective against a variety of organisms
Define conversed
Amino acids of polypeptide sequences or nucleotides of DNA sequences that remain consistent across species
Define deleterious mutation
A mutation that decreases the organism’s chances of survival and reproduction
Define deletion mutation
A mutation in which nucleotide pairs have been lost from a segment of DNA
Define double-strand break
A mutation involving breaks in the sugar-phosphate backbones at the nucleotide pair, resulting in the complete breakage of a chromosome
Define duplication
A mutation that occurs when one or more extra copies are made of a section of chromosome
Define extinct
When all the members of a population or species have died out
Define fitness
The capacity of an individual to survive and produce viable offspring
Define fixed
Describes an allele when it is the only variant available for a particular gene in the gene pool of a population
Define founder effect
The type of gene flow that occurs when a few individuals that have become isolated from a larger population do not carry all the alleles that were present in the original population
Define gene duplication
Generating an extra copy of a gene within a genome as a result of duplication of a chromosomal segment
Define gene flow
The tranfer of alleles that results from emigration and immigration of individuals between populations
Define gene pool
The range of genes and all their alleles present in a population
Define gene sequence
The sequence of nucleotides in a gene
Define genetic drift
The change in the gene pool of a population as a result of chance; usually occurs in small populations
Define genotype
A specific combination of alleles for a particular gene locus belonging to an individual
Define germline
A cell line in eukaryotic organisms from which the gametes are derived
Define heritable
Capable of being passed on to the next generation
Define horizontal gene transfer
The process by which genetic material from one organism becomes incorporated into the genome of another organism
Define insertion mutation
A mutation in which nucleotide pairs have been added to a segment of DNA
Define inversion mutation
A mutation resulting in the normal sequence of genes being reversed in a chromosome
Define missense mutation
A mutation that results in one amino acid being replaced by another amino acid in the encoded protein
Define monoculture
The practice of cultivating a single genetically uniform breed of plant or livestock
Define multidrug resistance
When a bacterium becomes resistant to two or more antibiotics
Define mutagen
An agent capable of inducing mutations
Define mutation
When a gene or chromosome has undergone a change relative to the original gene or chromosome; it may also refer to the process of generating such changes
Define natural selection
The process whereby individuals with certain heritable traits survive and reproduce more successfully than other individuals
Define neutral mutation
A mutation that has no effect on the organism’s chances of survival and reproduction
Define nonsense mutation
A mutation in which a codon for an amino acid is changed to one that codes for a stop codon, terminating translation
Define phenotype
The actual form taken by a specific feature in a particular individual based on their genotype; can be used in reference to particular traits or characteristics or to the overall form of an individual
Define point mutation
A mutation that affects a single base-pair position within a gene
Define population
A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring
Define population genetics
The study of allele frequencies in populations and how they change over time
Define selection pressure
A factor that favours the survival of some individuals over others within a population
Define selective breeding
Breeding of plants and animals over successive generations to produce traits that are desirable to humans; also known as ‘selective breeding’
Define silent mutation
A mutation in which the DNA codon for one amino acid becomes another DNA codon for the same amino acid; also referred to as a synonymous mutation
Define somatic
Describes a body cell that will not pass its genes on to the next generation
Define species
A group of similar organisms capable of breeding and exchanging genes with one another and whose offspring are capable of doing the same; also describes the lowest formal taxonomic rank and forms the second part of an organism’s scientific name
Define subspecies
The level of classification below species, referring to races of a species that are geographically isolated from each other
Define substitution mutation
A mutation in which a single nucleotide is swappd for another in the original gene sequence
Define synonymous mutation
A mutation in which the DNA codon for one amino acid becomes another DNA codon for the same amino acid; referred to as a silent mutation
Define translocation
A mutation occuring when a section of one chromosome breaks off and reattaches to another chromosome
Define absolute dating
The process of determining the age in years of rocks and the fossils they contain on the basis of the physical or chemical properties of materials in the rock
Define adaption
An anatomical, behavioural and physiological characteristic that allows an organism to exploit a specific ecological role
Define adaptive radiation
When a single species diversifies relatively rapidly into many new species because of the availability of many different ecological niches
Define allopatric speciation
Speciation that occurs when members of an ancestral population become geographically separated and each isolated population evolves into a new species
Define bioimformatics
The application of computer science to the digital storage, retrieval and analysis of large volumes of biological data
Define biological species concept
The concept that species are groups of natural populations that could potentially interbreed but are reproductively isolated from other populations
Define clade
A branch of a cladogram that represents a common ancestor and all of its descendants
Define cladogram
A phylogenic tree that depicts a hypothesis about the evolution of a group of organisms from a common ancestor
Define comparative dating
The process of determining the age of rocks and the fossils they contain relative to each other, allowing an estimation of ‘oldest to youngest’ without assigning an actual age in years
Define convergent evolution
When organisms that are not closely related independently evolve similar traits as a result of having to adapt to similar emvironments or ecological niches
Define correlation
The inference that rock layers located in distant sites must be of same age if they have identical mineral and fossil composition
Define divergent evolution
When members of a population develop adaptations to different selection pressures over many successive generations and eventually become new species
Define electron spin resonance
A method for determining the age of a rock or fossil based on the properties of electrons trapped inside the crystals of minerals
Define evolutionary distance
The number of substitutions that have occured in the amino acid sequences of homologous peptides or nucleotide sequences of homologous genes since two organisms diverged from a common ancestor
Define fossil
The preserved remains or traces of an organism
Define fossil record
The worldwide collection of fossils as they occur in the surface layers of Earth
Define fossil succession
When fossils appear in a consistent order in the fossil record from older rock layers to younger overlying rock layers; the same order is found worldwide
Define homologous
Refers to genes or polypeptides that have similar sequences and indicate a shared evolutionary ancestry
Define homologous structure
An anatomical feature in different organisms that has the same basic underlying structure but different functions
Define index fossil
A fossil that is representative of a specific geological time
Define isotope
One of two or more atoms of the same element witht he same atomic number and number of protons, but different numbers of neutrons and therefore different relative atomic masses
Define lineage
In evolution, a population that represents a separate line of descent from a common ancestor to modern species
Define luminescence
In absolute dating, a method for determining the age of a mineral crystal based on measuring the emission of light by elections as they are stimulated to ecape from the crystal
Definemass extinction
The extinction of many species over a relatively short (geological) period
Define maternally inherited
Describes a genotype that is transmitted entirely from the female parent to the offspring
Define mineralisation
The process by which minerals from sediments have replaced the biological matter in a deceased organism, making it prone to become a fossil
Define molecular clock
The number of substitutions that have accumulated in the amino acid sequence of a gene in a given lineage; the rate of the molecular clock is used to estimate the time since two species diverged
Define molecular homology
The similarity of patterns in the nulceotide sequences of DNA or amino acid sequences of polypeptides as evidence for a common evolutionary origin
Define monophyletic
Describes a taxonomic group of species that have all descended from the same common ancestor
Define morphological species concept
Usually applied to fossils, defines a species by measurable anatomical criteria and characteristics
Define mya
Millions of years ago
Define niche
An organism’s anatomcial role; the way the organism lives and functions in its environment
Define node
A junction point in a phylogenetic tree that represents thhe common ancestor of the lineages that diverges from it
Define optically stimulated luminescence
A luminescence techniuque that stimulates electrons to escape a mineral crystal when the crystall is exposed to coloured light
Define pairwise comparision
In evolutionary studies, a comparision between two polypeptide sequences, two DNA sequences or two genomes to determine how similar they are
Define phylogenetic tree
A branching diagram showing the evolutionary relationships between species; groups joined together in a tree are believed to have descended from a common ancestor
Define phylogeny
The evolutionary relationships that exist between species, often expressed as a tree-like diagram or represented by taxonomic classification
Define phylogram
A type of phylogenetic tree with branch lengths scaled to the number of nucleotide or amino acid changes that have occured during the evolution of each lineage
Define radioactive decay
A process by which the nucleus of an unstable isotope splits and emits energy in the form of radioactivity
Define radiometric dating
A method for determining the age of a rock or fossil based in the predictable rates of decay of naturally occuring radioactive isotopes present
oDefine relative dating
The process of determining the age of rocks and the fossils they contain relative to each other, allowing an estimation of ‘oldest to youngest’ without assigning an actual age in years
Define reproductively isolated
When sexual reproduction can no longerccur freely among any adult members of the population
Define sequence alignment
A display in which homologous polypeptide or DNA sequences are positioned against each other to identify patterns of conserved sequence
Define speciation
The evolution of one or more new species from an ancestral species
Define strata (singular: stratum)
Successive layers of sedimentary rocks; each layer represents a unique age range and contains a unique collection of fossils
Define structual morphology
The study of the physical structure and form of organisms
Define superposition
The principle that strata are deposited in a time sequnece, with the odest at the bottom and the youngest at the top
Define sympatric speciation
When two species evolve from an ancestral population while still inhabiting the same geographical area
Define taxonomy
A system of specific conventions for naming and classifying organisms
Define tetrapod
A ‘four-footed’ vertabre animal; includes amphibians, reptiels and mammals
Define thermoluminescence
A luminescence technique that stimulates electrons to escape a mineral crystal when the crystal is heated
Define trace fossil
A fossil produced by an organism’s activites, such as fossil footprints or burrows
Define transitional fossil
A fossil that bears features of both an older ancestral life form and a younger descendant
Define vestigal structure
A structure found in organisms that has lost most, if not all, of its original function in the course of evolution; in ancestral organisms, the structures served a purpose, but in hteir descendants, the structures become atrophied or rudimentary
Define aboreal
Related to, or living in, trees
Define australopithecine
A term for bipedal apes of the fossil genera Australopithecus and Paranthropus that inhabited eastern and sourthern Africa between 1.4 and at least 4.2 mya
Define bipedalism
A type of locomotion in which an organism walks on two hind limbs
Define braciation
A type of locomotion in which an organism swings between the limbs of trees
Define brain case
The part of the cranium that encloses the brain
Define brow ridge
A bony ridge above the eye sockets
Define carrying angle
The angle at which the femur is tilted in towards the knee
Define cerebal cortex
The outer most layer of the brain
Define cognitive capacity
An orgainism’s innate intelligence, ability to learn, play, evaluate, make decisions and apply new knowledge and skills
Define cranial capacity
The volume of the brain case
Define cranium
The skull, excluding the mandible
Define cultural evolution
The way beliefs, social practices, skills and technology change over time
Define Denisovan
A distinct, but undescribed, ancient hominin known primarily from bone fragments found in Denisova Cave in Siberia
Define dentition
Arrangement of teeth
Define exocrine gland
A gland that secretes a substance through a duct to the outer surface of the body
Define foramen magnum
The hole in the base of the skull through which the spinal cord passes
Define gracile
Of slender build
Define hallux
The big toe, or innermost toe of the foot
Define haplogroup
A group of organisms that have the same genetic mutations in a single chromosome and are descendants of a common ancestor through either maternal (mtDNA) or the paternal (Y chromosome) line of inheritance
Define haplotype
The unique combination of gentic mutations in the DNA sequences of a single chromosome (eg. mtDNA or Y chromosome) that are shared by different organisms and indicate common ancestry
Define hominin
A member of tribe Hominini; modern humans and their extinct bipedal ancestors
Define hominoid
A member of the superfamily Hominoidea; an ape, or tail-less primate
Define kya
Thousands of years ago
Define language
The system of spoken or written communication comprising distinctive words and the rules by which the words are organised and expressed
Define mammal
A warm-blooded vertabrae animal that has hair or fur, and the females secrete milk to nourish their offspring
Define mammary gland
A gland in female mammals that produces milk
Define mandible
The lower jawbone of the skull
Define midden
A pile of discarded waste left by humans in the past
Define Out of Africa hypothesis
A hypothesis that modern humans evolved in Africa and subsequently migrated out and colonised the other continents; also known as recent single origin
Define oviparous
An animal that lays eggs that are expelled from the body and from which juveniles hatch
Define paleoanthropology
The field of study concerned with fossil hominins
Define placental
Describes an animal in which the foetus develops inside the mother whie attached to an organ that provides nutrients and oxygen and removes waste
Define postcranial
All of the skeleton, except the skull
Define precision grip
A grip defined by the tips of the thumb and fingers pressing together to finely manipulate an object
Define prefrontal cortex
The portion of cerebral cortex that covers the front part of the brain
Define prehensile
Capable of curling and grasping
Define primate
A member of the order Primata; includes lemurs, lorises, tarsiers, monkeys, apes and modern humans
Define prognathism
A condition in which the jaws protrude from the plane of the face
Define quadrupedalism
A type of locomotion in which an organism walks on four limbs
Define recent single origin
A hypothesis that modern humans evolved in Africa and subsequently migrated out and colonised the other continents; also known as Out of Africa hypothesis
Define robust
Of sturdy build
Define sagittal crest
A prominent raised bony ridge along the midline of the skull
Define sagittal keel
A thickening of bone along the midline of the skull
Define sebaceous gland
A gland in the skin that secretes oils that lubricate and protect patches of skin and hair
Define sexual dimorphism
Where males and females of a species have different morphologies, often in shape and size
Define stereoscopic
Describes vision that has a sense of depth
Define superfamily
A taxonomic rank immediately superior to the traditional rank of family; a superfamily may contain multiple taxonomic families
Define suspensory locomotion
A type of locomotion in which an organism hangs or moves beneath the limbs of trees
Define sweat gland
A gland in the skin that secretes sweat
Define tribe
A taxonomic rank inserted between family and genus
Define viviparous
An animal that gives birth to live young
