Ch 10 How We Are Related Flashcards

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1
Q

Fossil record

A

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.

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2
Q

Cambrian explosion

A

A period (~ 535 mya) of rapid diversification of multicellular life, characterised by the evolution of hardened body parts such as shells or bones.

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3
Q

Extinction

A

The dying out of a species on a global or regional level.

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4
Q

Fossil

A

The preserved body, impressions, or traces of a dead organism.

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5
Q

Fossilisation

A

The process by which an organism becomes a fossil.

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6
Q

Sediment

A

Naturally occurring solid material, such as earth and rock, that is broken down into very fine pieces and typically settles at the bottom of liquid.

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7
Q

Sedimentary rock

A

Rock that has formed through the accumulation of sediment that hardens under pressure.

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8
Q

Permineralised fossil

A

Fossil formed when mineral-rich groundwater deposits minerals like silica and calcite into organic material, creating a mineral relic.

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9
Q

Mould fossil

A

Fossil formed when a living thing decomposes underneath sediment, creating a cavity in the shape of the dead organism.

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10
Q

Cast fossil

A

Fossil formed when a mould fossil is filled with sediment.

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11
Q

Trace fossil

A

Fossil or structure indicating the presence of organisms, rather than the organisms themselves (e.g. nests, footprints, and burrows)

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12
Q

Relative dating

A

A dating technique used to determine the relative age of a fossil by comparing its position to other fossils or rock in surrounding rock strata (layers).

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13
Q

Absolute dating

A

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.

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14
Q

Fossil succession

A

The principle that fossils of the same age will be in the same layer of sedimentary rock, and fossils found in higher or lower sedimentary layer will be younger or older, respectively. Also known as faunal succession.

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15
Q

Relative age

A

The age of a fossil as determined by relative dating techniques. Describes the age of a fossil compared to other fossils, instead of a fossil’s exact age in years.

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16
Q

Stratum (pl. strata)

A

A layer of sedimentary rock.

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17
Q

Index fossil

A

A group of widespread fossils which existed for a short period and have a known age. Can be used as a reference to easily determine the age of unknown fossils.

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18
Q

Transitional fossil

A

A fossil that shows traits that are common to both its ancestral group and its descendant group. They are particularly important when the descendant species is physically very distinct from the ancestral species, such that the transitional fossil can help demonstrate evolutionary changes between the two.

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19
Q

Absolute age

A

An estimate of the age (in years) of a fossil or rock.

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20
Q

Radioactive isotope

A

A radioactive atom of a specific element. This atom breaks down into a predictable and stable product. Also known as a radioisotope.

21
Q

Half-life

A

The time taken for half the mass of a radioisotope sample to break down into its products.

22
Q

Dating period

A

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.

23
Q

Radiocarbon dating

A

A form of absolute dating used to determine the age of a fossil by measuring the properties of radiocarbon, a radioactive isotope of carbon. Also known as carbon dating and radioactive carbon dating.

24
Q

Structural morphology

A

The study of physical structures to establish relatedness.

25
Q

Homologous structure

A

Features present in two or more species that may look and function very differently in each species, but are derived from a common ancestor.

26
Q

Divergent evolution

A

The process in which a common ancestor evolves into two or more descendant species.

27
Q

Analogous structures

A

Features present in two or more species that fulfil the same function but do not originate from a common ancestor.

28
Q

Convergent evolution

A

The process in which distantly related species evolve similar traits over time due to the action of similar selection pressures.

29
Q

Vestigial structures

A

Features that have lost all or most of their usefulness as a result of evolution by natural selection.

30
Q

Molecular homology

A

The study of the similarities in the nucleotide sequences of DNA or amino acid sequences in proteins between organisms to establish relatedness.

31
Q

Conserved genes

A

Genes that have remained largely unchanged throughout evolution, and are found across the genome’s of many different species.

32
Q

Haemoglobin (Hb)

A

A protein found in red blood cells that is responsible for the transport of oxygen in the body.

33
Q

Cytochrome c

A

An enzyme found in mitochondria that carries electrons In aerobic and anaerobic respiration reactions.

34
Q

Mitochondrial DNA (mtDNA)

A

Circular DNA found in mitochondria.

35
Q

DNA (deoxyribonucleic acid)

A

A double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival.

36
Q

Nucleotide

A

The monomer subunit of nucleic acids. Made up of a nitrogen-containing base, a five-carbon sugar molecule (ribose in RNA and deoxyribose in DNA), and a phosphate group.

37
Q

Genome

A

The complete set of DNA housed within an organism.

38
Q

Nuclear DNA

A

DNA that is located in the nucleus of a cell.

39
Q

Phylogenetics

A

The study of the relatedness between organisms.

40
Q

Phylogenetic tree

A

A diagram used to show the relatedness between organisms.

41
Q

Evolutionary relationship

A

The relatedness of organisms based on shared ancestry.

42
Q

Lineage

A

A direct sequence of species that evolved from a common ancestor.

43
Q

Taxon (pl. taxa)

A

A unit of biological classification into which related organisms are classified. Taxa are arranged in a hierarchical rank from kingdom down to species, where members of a specific taxon typically share certain morphological characteristics.

44
Q

Root

A

Represents the most recent common ancestor for all members of a phylogenetic tree.

45
Q

Branch

A

A line on a phylogenetic tree that represents an evolutionary path.

46
Q

Node

A

The splitting point between two branches on a phylogenetic tree, representing a speciation event.

47
Q

Leaf

A

The end of a branch that shows the current (or final) form of a species.

48
Q

Adaptive radiation

A

The rapid divergent evolution of a species, thereby producing a wide array of species/forms.