chap 10- glossary Flashcards
absolute dating
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.
adaptation
Adaptation- an anatomical, behavioural and physiological characteristic that allows an organism to exploit a specific ecological role.
adaptive radiation
Adaptive radiation- when a single species diversifies relatively rapidly into many new species because of the availability of many ecological niches.
allopatric speciation
Allopatric speciation- speciation that occurs when members of an ancestral population become geographically separated and each isolated population evolves into a new species.
analogous structure
Analogous structure- an anatomical or morphological feature in different organisms thar has the same function but not the same basic underlying structure.
bioinformatics
Bioinformatics- the application of computer science to the digital storage, retrieval and analysis of large volumes of biological data.
biological species concept
Biological species concept- the concept that species are groups of natural populations that could potentially interbreed but are reproductively isolated from other populations.
clade
Clade- a branch of a cladogram that represents a common ancestor and all of its descendants.
gladogram
Cladogram- a phylogenetic tree that depicts a hypothesis about the evolution of a group of organisms from a common ancestor.
convergent evolution
Convergent evolution- when organisms that aren’t closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.
correlation
Correlation- the inference that rock layers located in distant sites must be of the same age if they have identical mineral and fossil composition.
divergent evolution
Divergent Evolution- when members of a population develop adaptations to different selection pressures over many successive generations and eventually become new species.
electron spin resonance
Electron spin resonance- a method for determining the age of a rock or fossil based on the properties of electrons trapped inside the crystals or minerals.
evolutionary distance
Evolutionary distance- the number of substitutions that have occurred in the amino acid sequences of homologous polypeptides or nucleotide sequences of homologous genes since two organisms diverged from a common ancestor.
fossil
Fossil- the preserved remains or traces of an organism.
fossil record
Fossil record- the worldwide collection of fossils as they occur in the surface layers of Earth.
fossil succession
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.
homologous
Homologous- refers to genes or polypeptides that have similar sequences and indicate a shared evolutionary ancestry.
homologous structure
Homologous structure- an anatomical feature in different organisms that has the same basic underlying structure but different functions.
index fossil
Index fossil- a fossil that is representative of a specific geological time.
isotope
Isotope- one of two or more atoms of the same element with the same atomic number and number of protons, but different numbers of neutrons and therefore different relative atomic masses.
lineage
Lineage- in evolution, a population that represents a separate line of descent from a common ancestor to modern species.
luminescence
Luminescence- in absolute dating, a method for determining the age of a mineral crystal based on measuring the emission of light by electrons as they are stimulated to escape from the crystal.
mass extinction
Mass extinction- the extinction of many species over a relatively short (geological) period.
maternally inherited
Maternally inherited- describes a genotype that is transmitted entirely from the female parent to the offspring.
mineralisation
Mineralisation- the process by which minerals from sediments have replaced the biological matter in a decreased organism, making it prone to become a fossil.
molecular clock
Molecular clock- the number of substitutions that have accumulated in the amino acid sequence of a polypeptide or the nucleotide sequence of a gene in a given lineage; the rate of the molecular clock is used to estimate the time since two species diverged.
molecular homology
Molecular homology- the similarity of patterns in the nucleotide sequences of DNA or amino acid sequences of polypeptides as evidence for a common evolutionary origin.
monophyletic
Monophyletic- describes a taxonomic group of species that have all descended from the same common ancestor.
morphological species concept
Morphological species concept- usually applied to fossils, defines a species by measurable anatomical criteria and characteristics.
mya
millions of years ago
niche
Niche- an organisms ecological role, the way the organism lives and functions in its environment.
node
Node- a junction point in a phylogenetic tree that represents the common ancestor of the lineage that diverge from it.
optically stimulated luminescence
Optically stimulated luminescence- a luminescence technique that stimulates electrons to escape a mineral crystal is exposed to coloured light.
pairwise comparison
Pairwise comparison- in evolutionary studies, a comparison between two polypeptide sequences, two DNA sequences or two genomes to determine how similar they are.
phylogenetic tree
Phylogenetic tree- a branching diagram showing the evolutionary relationships between species, groups joined together in the tree are believed to have descended from a common ancestor.
phylogeny
Phylogeny- the evolutionary relationships that exist between species, often expressed as a tree-like diagram or represented by a taxonomic classification.
phylogram
Phylogram- a type pf phylogenetic tree with branch lengths scaled to represent the number of nucleotide or amino acid changes that have occurred during the evolution of each lineage.
radioactive decay
Radioactive decay- a process by which the nucleus of an unstable isotope splits and emits energy in the form of radioactivity.
radiometric dating
Radiometric dating- a method for determining the age of a rock or fossil based on the predictable rates of decay of naturally occurring radioactive isotopes present.
relative dating
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.
reproductively isolated
Reproductively isolated- when sexual reproduction can no longer occur freely among any adult members of the population.
sequence alignment
Sequence alignment- a display in which homologous polypeptide or DNA sequences are positioned against each other to identify patterns of conserved sequence.
speciation
Speciation- the evolution of one or more new species from an ancestral species.
strata
Strata- (singular stratum) successive layers of sedimentary rocks; each layer represents a unique age range and contains a unique collection of fossils.
structural morphology
Structural morphology- the study of the physical structure and form or organisms.
superposition
Superposition- the principle that strata are deposited in a time sequence, with the oldest at the bottom and the youngest at the top.
sympatric speciation
Sympatric speciation- when two species evolve from an ancestral population while still inhabiting the same geographical area.
taxonomy
Taxonomy- a system of scientific conventions for naming and classifying organisms.
tetrapod
Tetrapod- a ‘four-footed’ vertebrate animal; includes amphibians, reptiles and mammals.
thermoluminescence
Thermoluminescence- a luminescence technique that stimulates electrons to escape a mineral crystal wen the crystal is heated.
trace fossil
Trace fossil- a fossil produced by an organisms activities, such as fossil footprints or burrows.
transitional fossil
Transitional fossil- a fossil that bears features of both an older ancestral life form and a younger descendent.
vestigial structure
Vestigial 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 their descendants, the structures become trophied or rudimentary.
