Start What is relative dating of fossils

What is relative dating of fossils

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.

Peaks on the landscape correspond to genotypic frequencies at which the average fitness is high, valleys to genotypic frequencies at which the average fitness is low. adaptive logic: A behavior has adaptive logic if it tends to increase the number of offspring that an individual contributes to the next and following generations.

If such a behavior is even partly genetically determined, it will tend to become widespread in the population.

Amphibian larvae are aquatic, and have gills for respiration; they undergo metamorphosis to the adult form.

Most amphibians are found in damp environments and they occur on all continents except Antarctica.

Allometric relations can be studied during the growth of a single organism, between different organisms within a species, or between organisms in different species. amino acid: The unit molecular building block of proteins, which are chains of amino acids in a certain sequence.

allopatric speciation: Speciation that occurs when two or more populations of a species are geographically isolated from one another sufficiently that they do not interbreed. There are 20 main amino acids in the proteins of living things, and the properties of a protein are determined by its particular amino acid sequence.

Also used to describe the process of genetic change within a population, as influenced by natural selection.

adaptive landscape: A graph of the average fitness of a population in relation to the frequencies of genotypes in it.

allometry: The relation between the size of an organism and the size of any of its parts.

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.

Right: A crushed ammonite from the Shales-with-Beef Member, found on the foreshore beneath Black Ven.