Effective range of radiocarbon dating
They have moist scaleless skin which is used to supplement the lungs in gas exchange.The eggs are soft and vulnerable to drying, therefore reproduction commonly occurs in water.
For example, an allometric relation exists between brain size and body size, such that (in this case) animals with bigger bodies tend to have bigger brains.analogous structures: Structures in different species that look alike or perform similar functions (e.g., the wings of butterflies and the wings of birds) that have evolved convergently but do not develop from similar groups of embryological tissues, and that have not evolved from similar structures known to be shared by common ancestors. Note: The recent discovery of deep genetic homologies has brought new interest, new information, and discussion to the classical concepts of analogous and homologous structures.anatomy: (1) The structure of an organism or one of its parts. ancestral homology: Homology that evolved before the common ancestor of a set of species, and which is present in other species outside that set of species. anthropoid: A member of the group of primates made up of monkeys, apes, and humans.ammonoid: Extinct relatives of cephalopods (squid, octopi, and chambered nautiluses), these mollusks had coiled shells and are found in the fossil record of the Cretaceous period.amniotes: The group of reptiles, birds, and mammals.
acquired trait: A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large muscles of a weightlifter).