Chapter 10 - How we are related Flashcards
absolute age
an estimate of the age (in years) of a fossil or rock
absolute dating
a dating technique used to determine the absolute age of a fossil by measuring the relative amounts of radioisotopes to their products. Also known as radiometric dating
adaptive radiation
the rapid divergent evolution of a species, thereby producing a wide array of species/forms
analogous structures
features present in two or more species that fulfil the same function but do not originate from a common ancestor
branch
a line on a phylogenetic tree that represents an evolutionary path
Cambrian explosion
a period (~535 mya) of rapid diversification of multicellular life, characterised by the evolution of hardened body parts such as shells or bones
cast fossil
fossil formed when a mould fossil is filled with sediment
conserved genes
genes that have remained largely unchanged throughout evolution, and are found across the genome’s of many different species
convergent evolution
the process in which distantly related species evolve similar traits over time due to the action of similar selection pressures
cytochrome c
an enzyme found in mitochondria that carries electrons in aerobic and anaerobic respiration reactions
dating period
the range of time since fossilisation in which a particular radioisotope series can be used. Beyond this period, most of the radioisotope will have broken down into its products, meaning that it is too difficult to estimate the fossil’s age
divergent evolution
the process in which a common ancestor evolves into two or more descendant species
DNA (deoxyribonucleic acid)
a double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival
evolutionary relationship
the relatedness of organisms based on shared ancestry
extinction
the dying out of a species on a global or regional level
fossil
the preserved body, impressions, or traces of a dead organism
fossil record
the information derived from fossils. The fossil record is arranged in chronological order and helps us map the history of life on Earth, placing species in the appropriate geologic time frame
fossil succession
the principle that fossils of the same age will be in the same layer of sedimentary rock, and fossils found in a higher or lower sedimentary layer will be younger or older, respectively. Also known as faunal succession
fossilisation
the process by which an organism becomes a fossil