The Vertebrate Anatomy ( chapter 2)

• The first skeletal structure in vertebrates is the notochord, which extends from the midbrain to the tip of the tail.
• The dorsal hollow central nervous system, or neurocoele, is a central lumen or canal of the CNS that arises from the neural groove.
• The post anal tail is a posterior elongation of the body extending beyond the anus, mostly for locomotory function to chordates that retain this characteristic.
• Pharyngeal slits, or gill slits, are a glandular groove in the floor of the pharynx that appear early in embryonic development.
• Chordates are animals that have a notochord during the embryo stage at least.
• Acraniates are chordates without a cranium.
• Craniates are chordates with a cranium.
• Vertebrates are chordates with vertebrae.
• The typical regional components of the craniate body are the head, trunk, and post anal tail.
• The head of a craniate is typically associated with special sense organs, the brain, jaws, gills, and has a greater degree of cephalization than in any other group of animals.
• The trunk of a craniate is associated with the coelom, which houses most of the viscera, and consists of the body wall, which surrounds the coelom, and consists chiefly of muscle, vertebral column, ribs, and paired pectoral and pelvic appendages.
• Morphological homology is when species (correctly) placed in the same taxonomic category show anatomical similarities.
• The very existence of DNA in every living thing on earth is, in itself, strong evidence of common ancestry.
• The most striking vertebrate adaptation is the transition from water to land.
• The similarities of embryo development of different species are remnants of the embryonic development features of those species' common ancestor.
• Haeckel was the first to notice that the embryonic forms of different species had amazing physical similarities.
• Behavioral adaptations are adaptive behavior based on environmental stimuli and respond to life needs, including seasonal migration of animals, hibernation, aestivation, huddling (penguins), nocturnal, and staying in group.
• Humans did not evolve from monkeys, but share a common ancestor with them.
• Structural adaptations are physical features of the organisms that are helpful for their survival in a natural habitat, including color of the skin, body shape, body covering, body size, limbs for motility, and thick skin of reptiles.
• Evolution is a process of gradual "remodeling" of a body plan by both random events and natural selection.
• Monkeys still exist because they descended from successful ancestors.
• Homology is a characteristic shared by two species (or other taxa) that are similar because of common ancestry.
• The deepest level of homology: The molecules that carry the instructions for making and running our bodies are encoded in our DNA.
• Evolution proceeds by incremental changes to the raw material that's already present in any given population of organisms.
• Once on land, vertebrates evolved to occupy diverse habitats and live very active lifestyles.
• The tail of a craniate starts at the anus or vent and consists of the caudal continuation of the body wall muscles, axial skeleton, nerves, and blood vessels.
• The more closely related two species are, the more similar their DNA sequences.
• Ontogenetic homology is when species placed in the same taxonomic category show developmental (embryological) similarities.
• The evolutionary history of a species can be seen in its DNA sequences.
• Molecular homology is when species placed in the same taxonomic category show similarities in DNA, RNA and protein.
• All living things give birth to offspring that are fairly similar to themselves.
• Metamerism is the serial repetition of structures in the longitudinal axis of the body, clearly manifested in craniate embryos and is retained in many adult systems.
• Craniate characteristics include the cranium, three-part brain, neural crest and its derivatives.
• Pharyngeal pouches give rise to middle ear cavity of tetrapods, provide initial cells of immune system during fetal life and shortly after, and contain endocrine glands, other tissues, and circulating blood.
• During development, the head region of notochord is incorporated into the floor of skull, and the trunk and tail are surrounded by cartilaginous or bony vertebrae.
• Postanal tail appears in all embryonic stages and is still present in some adult chordates.
• In fishes and amphibians, notochord persists the length of the trunk and tail but is constricted within the centrum of each vertebra.
• Notochord is a rod of living cells ventral to cns and dorsal to alimentary canal, the first skeletal structure to appear in craniate embryos, and is derived from mesoderm.
• Pharyngeal pouches arise as diverticula of endoderm of foregut, grow toward the surface of animal, and establish the limits of pharynx.
• A question often posed by folks who do not understand evolutionary mechanisms is: "If humans evolved from monkeys, then why are there still monkeys?"