Unit 4: AOS 2: Glossary Flashcards
What is a genotype?
the genetic make-up or the combination of alleles for a particular gene of an organism
What is a Phenotype?
a physical characteristic determined by genotype and environment
What is Genetic diversity?
the genetic variability within a spices
What are adaptations?
the behavioural, physiological and structural features of an organism that help them survive in an environment
What is a population?
a group of individuals of the same species living in the same region at a given time
What are species?
a group of organisms that can interbreed, producing fertile and viable offspring
What is a gene pool?
the sum total of alleles present in a population of organisms
What is an Allele frequency?
the porpution of a particular allele within a population
What is evolution?
a change in the allele frequencies if a population over time
What is a mutation?
A permanent change in the nucleotide sequence of a section of DNA
What is a mutagenic agent?
agents known to cause mutations; e.g some radiation source and chemicals; also called mutagens
What is point mutation?
a change to one base in the nucleotide sequence of a section of DNA; includes base substitutions and frameshift mutations
What is Substitution mutation?
a type of point mutation that occurs when one nitrogenous base in a gene is replaced with another base; includes silent, missense and nonsense mutations
What is a silent mutation?
a mutation where the change in the nucleotide sequence doesn’t change the amino acid that is coded for
What is a Missenese mutation?
a mutation in which the base change in the nucleotide sequence of the DNA changes the amino acid that is coded for; a type of substitution point mutation
What is nonsense mutation?
a mutation that occurs when the base changes in the nucleotide sequence of the DNA codes for a STOP codon, prematurely halting the production of the polypeptide; a type of substitution point mutation
What is frameshift mutation?
a type of point mutation that occurs when one base is inserted into or deleted, causing an incorrect reading of the codons due to a shift in the reading frame
What is block mutation?
a type of mutation that affects large sections of DNA, typically containing multiple genes; also called chromosome mutation
What is Chromosome abnormality?
mutation that involves a whole chromosome, or a change in the number of chromosomes, which can be identifies using a karyotype; e.g aneuploidy and polyploidy
What is Karyotype?
a pictorial representation of chromosomes that allows a geneticist to determine size, banding pattern, shape and number of chromosomes in an individual’s somatic cell; allows the determination of diploid number, gender and chromosomal abnormalities
What is a Aneuploidy?
when a cell has one more or one less chromosome than expected, usually due to non-disjunction
What is Polyploidy?
a condition in which an organism has more than 2 full sets of chromosomes in its cells; more common in plants than animals
What is gene flow?
the exchange of genetic information, specifically alleles, between populations
What is genetic drift?
a random change in allele frequency, occurring naturally in every population, due to chance events
What is the Bottleneck effect
when a population is drastically reduced to low numbers by a random or chance event and the allele frequencies of the surviving population do not reflect the genetic diversity of the original population
What is the founder effect?
when a small sample of a large population moves away to colonise a new area and become isolated; the allele frequencies of the founder population do not represent the genetic diversity of the larger original population
What are selection pressures?
the conditions or factors that influence allele frequencies in a population by contributing to the selection of which phenotypes survive in a given environment e.g resources, environmental conditions, predators and disease
What is natural selection?
an evolutionary process whereby those individuals in a population that have a particular set of alleles are best suited to the environment and will survive, reproduce and pass on their genetic information to the next generation
What is selective advantage?
a trait or phenotype that provides a survival advantage
What is selective breeding or artificial selection
a process whereby humans intervene in the breeding of a species to keep desired features in a population that are economically beneficial or aesthetically pleasing, by selecting which organisms are to reproduce
What is bacterial resistance?
the ability of bacteria to survive and reproduce in the presence of an antibiotic that has been designed to slow their growth or kill them; arises by mutation and becomes widespread when antibiotics are overused
Whaat is conjugation?
the process by which genetic material is exchanged between a donor bacterium; occurs through a tube via direct cell-cell contact; also known as horizontal gene transfer
What is a pandemic?
the outbreak of infectious disease that occurs over a wide geographical area, affecting a large number of people
What is a epidemic?
the raid spread of an infectious disease to a large number of people within a population
What is antigenic drift?
mutations altering viral surface antigens, making the virus unrecognisable to the host’s immune system; can result in a epidemic
What is antigenic shift?
reassortment of genes on genomes from different viruses infecting the same host cell, altering viral surface antigens, resulting in novel strains that can cause pandemics
What does fertile mean?
able to reproduce
what does viable mean?
able to survive
What does speciation mean?
the evolutionary process of forming a new species from a pre-existing ancestral species
what does reproductive isolation mean?
the inability of two groups of organisms to interbreed successfully; genetic isolation also ensures there is no gene flow between the two populations
what does allopatric speciation mean?
a form of speciation that occurs when a geographical barrier physically divides a population; the two sub-populations accumulate so many genetic differences that they become reproductively isolated and are considered different species
What does sympatric speciation mean?
a form of speciation that occurs without the involvement of a physical barrier; often occurs in plants as a consequence of polyploidy.
What does divergent evolution mean?
where two or more species form from a single ancestral species over time
What is adaptive radiation?
the rapid diversification of a large number of related species from a single ancestral species
What are plate tectonics?
a scientific theory that focus on the separation of earth’s crust into plates that move across the underlaying mantle
What is the geological time scale?
a scale dividing earth’s history into intervals according to the geological and biological events and conditions present at that time
what does biodiversity mean?
the variety of plant and animal like in an ecosystem at any given time
what does period mean?
a time interval characterised by specific rock layers; periods are subdivisions of eras
what is an era?
a subdivision of an eon
what is a eon?
a long period of time that consists of at least two eras
what is a supereon?
a period of geological time that consists of more than one eon
What is a cyanobacteria?
a group of prokaryotic microorganisms that are capable of photosynthesis; recognised as the earliest form of life on Earth
What is a stromatolite?
a structure that consists of layered deposits made by cyanobacterial colonies; fossilised stromatolites are among the earliest fossils known
What is an invertabrate?
an organism that does not have a backbone
What is a Cambrian explosion?
a rapid increase in complex biodiversity within the fossil record that occurred at the beginning of the Cambrian period
What is a arthropod?
a type of animal that has no internal backbone, a segmented body and a hard, external covering known as an exoskeleton
What is a Brachiopod?
a marine animal with no internal backbone and a hinged upper and lower shell
What is a chrodate?
any animal that contain evidence of a spinal cord at some point in its developement
What is vertebrate?
having a backbone
What is a myriapod?
a subphylum of mostly terrestrial arthropods including millipedes, centipedes and other ‘many-legged’ invertebrates
What is a tetrapod?
any vertebrate animals that has four legs or limb-like e.g amphibians, reptiles, birds and mammals
What are amphilbians?
a class of tetrapods that are semi-terrestrial, with young living in water before moving to land as adults; e.g frogs, toads and salamanders
What are reptiles?
a class of air-breathing tetrapods with skin covered in scales, that lay eggs on land
What is a niche?
the role that a species plays within a ecosystem?
What is the background extinction rate?
the normal extinction rate to be expected to occur over a period of time due to natural environmental factors
What is a fossil?
the remains or traces of a pre-existing life form
What is a fossil record?
a record of organisms that once lived, through geological time, as documented by fossils
what is a trace fossil?
fossilised signs or remains of an organism’s activity, e.g tracks
What is a petrification?
the replacement of an organism’s organic matter with minerals, turning it into a stony material.
What is a mould fossil?
an impression that forms from the decay of the organism within a rock
What is a cast fossil?
fossil formed when an organism decays, leaving an impression which fills, with minerals, resulting in a 3D object of the organism’s external surface
What is a sedimentary rock?
a type of rock that is formed from the accumulation of sediment into layers
What is a metamorphic rock?
a type of rock that arises from the transforming of existing rocks
What is absolute dating?
determines the actual age of specimen being analysed
What is relative dating?
determines the age of a specimen by comparing its placement with that of other fossils or the rock layers it is found in
What is a index fossil?
a fossil that is used ti date and correlate the strata within which it is found
What is a half-life?
the time taken for 50% of an unstable parent isotope to decay into its corresponding stable daughter isotope
What is a homologous structure?
a structure within a group of species that performs a different function yet has the same underlying structure
What is a divergent evolution?
where two or more species form from a single ancestral species over time
What is a vestigial structure?
a structure within an organism that is no longer functional but served a purpose in a common ancestor
What is a primate?
the order of consisting all current and extinct humans, apes, and monkeys, characterised by having dextrose hands with opposable thumbs and a relatively large and developed brain
What is molecular homology?
the analysis of DNA and amino acid sequences as evidence of evolutionary relationships
What is a phylogeny?
a branch of service that studies the evolutionary relationships between a group of species
What is a Phylogenetic tree?
a branching diagram used to represent the evolutionary relationships between species
What is Taxonomy?
the process of identifying, naming and grouping organisms
What is a molecular phylogency?
comparison of nucleotide sequence of genes and amino acid sequence of proteins, from which evolutionary relationships can be inferred
What is a Hominoid?
the superfamily consisting of all current and extinct humans and apes
What is a Hominin?
the subfamily consisting of all current and extinct bipedal primates
What does Bipedal mean?
able to walk on two legs or upright
what is a genus?
a group of related organisms that share a recent common ancestor
What is a species?
a group of organisms that can interbreed, producing fertile and viable offspring
What does Foramen magnum mean?
Hole in the base of the skull through which the spinal cord enters/exists the skull
What is the molecular clock?
using the predicted mutation rate of DNA (or amino acid) sequences to determine the approximate time at which two species diverged
What does interbreed mean?
mate with an organism of another species (sometimes used between different genetic groups or population)
What does Bipedalism mean?
the characteristic of being bipedal, i.e walking upright on two legs
What does connection to country mean?
the relationship between people and their indigenous land or environment
What does Putative mean?
a term used to describe something that is expected or assumed to have existed, without any current direct proof
What is Structural morphology?
the study of an organism’s features and form to determine the evolutionary relationship of species
