Echinoderm microfossil dating
The term refers to a spatial gradient in any measurable characteristic—for example, allele frequency or the mean of a quantitative trait.Subdivision of molecules, cells, or genetic functions into discrete spatial or temporal units.Member of a major subdivision within the protostomes that includes the arthropods, nematodes, and several smaller phyla.Members of this group possess an external covering called a cuticle that molts as the animal grows.These are common in the genomes of some bacterial pathogens.Member of a major animal phylum of solitary gelatinous marine animals commonly called comb jellies or sea gooseberries (phylum Ctenophora).It is calculated as the ratio of the minimum number of evolutionary state changes (aka steps) that could be seen from all possible trees divided by the actual number of changes on the tree being examined.Loci made up of microsatellite repeats (e.g., ATATATAT) in which, when the number of copies of the repeat changes, the phenotype of the cell changes drastically.
A A Drosophila chromosome that carries multiple inversions, recessive lethals, and dominant markers.
The length of a particular branch in an evolutionary tree.
In certain types of evolutionary trees, the branch length is used to represent the amount of evolutionary change or time.
Any worm of the phylum Chaetognatha, commonly called an arrowworm.
This is a transparent marine worm with horizontal lateral and caudal fins and a row of movable curved spines at each side of the mouth. Used in phylogenetic analysis and to study the evolution of traits over time.
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Members of this group have rows of small combs composed of cilia that are used for locomotion.