Anatomy
YIGDAL
Terms
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- Stabilizing Selection
- type of natural selection in which the average for of the trait is favored and becomes more common.
- Genetic Drift
- changes in the gene pool of a small population due to chance. Tends to reduce genetic variation.
- Convergent
- The adaptive evolution of superficially similar structures, such as the wings of birds and insects, in unrelated species subjected to similar environments. Also called convergent evolution.
- Segmentation
- the act of dividing or partitioning
- Microevolution
- evolution resulting from small specific genetic changes that can lead to a new subspecies
- Ozone
- a colorless gas (O3) soluble in alkalis and cold water
- Gill Slits
- found in the region between the mouth and hte digestive tube as a pair of openings to the outside.
- Dorsal
- belonging to or on or near the back or upper surface of an animal or organ or part
- Epithelium
- membranous tissue covering internal organs and other internal surfaces of the body
- Paraphyletic
- pertaining to a grouping of species that consists of an ancestral species and some, but not all, of its descenants
- Dorsal Tubular Nerve Chord
- Hollow nerve chord on the backside of the animal. the hollow portion of the nerve chord is filled with fluid that nourishes the nerve cells, and in the vertebrates the vertebrae surround and protect the nerve chord creating the spine.
- Polyphyletic
- descendants of more than one most recent common ancestor
- Acoelomates
- animals w/o coelem
- Connective Tissue
- binds and supports other tissues; characterized by sparse cells in an extracellular gel matrix
- Cnidaria
- Diploblastic; digestive cavity w/ tentacles; jellyfish, hydras, sea anemones
- Endostyle
- a longitudinal ciliated groove on the ventral wall of the pharynx which produces mucus to gather food particles
- Prokaryote
- a unicellular organism having cells lacking membrane-bound nuclei
- Malthus
- an English economist who argued that increases in population would outgrow increases in the means of subsistence (1766-1834)
- Echinoderms
- Invertebrates that have spiny skin and tube feet such as sea stars, urchins and sand dollars
- Anterior
- of or near the head end or toward the front plane of the body
- Prostomates
- first mouth, then anus
- Chemical Evolution
- The formation of complex organic molecules from simpler inorganic molecules through chemical reactions in the oceans during the early history of the Earth; the first step in the development of life on this planet.
- Notochord
- a flexible rodlike structure that forms the supporting axis of the body in the lowest chordates and lowest vertebrates and in embryos of higher vertebrates
- Platyhelminthes
- Flatworms, flukes; first triploblasts and bilateria; acoelomates; can be parasitic; regeneration
- Analogous
- corresponding in function but not in evolutionary origin
- Directional Selection
- when natural selection favors a single allele and therefore, allele frequency continuously shifts in one direction
- Ectoderm
- the outer germ layer that develops into skin and nervous tissue
- Cephalization
- concentration of feeding organs, sensors, and neural structures at the anterior end, the part of the body most likely to make first contact with food or threatening stimuli.
- Speciation
- evolution of a new species. occurs when organisms in a species can no longer interbreed (geographic isolation and reproductive isolation).
- Founder Effect
- when a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool isn't reflective of the source population
- Coelomate
- Animal that possesses a true coelom
- Sexual Reproduction
- reproduction involving the union or fusion of a male and a female gamete
- Arthropods
- A group of organisms that have jointed appendages, an exoskeleton, bilateral symmetry, and reproduce sexually; insects, arachnids, millipedes and cenitpedes, and crustaceans
- Complete Digestive System
- food processing occurs within a tube-like enclosure, the alimentary canal, running lengthwise through the body from mouth to anus. Ingested food usually travels in only one direction
- Incomplete Digestive System
- a single opening to a pouch-like cavity serves as both mouth and anus
- Muscle Tissue
- composed of long cells that are capable of contracting usually when stimulated by nerve signals
- Homologous
- having the same evolutionary origin but serving different functions
- Divergent
- The evolutionary tendency or process by which animals or plants that are descended from a common ancestor evolve into different forms when living under different conditions.
- Eukaryote
- an organism consisting of cells that have a nucleus enclosed by a membrane.
- Macroevolution
- evolution on a large scale extending over geologic era and resulting in the formation of new taxonomic groups
- Nerve Tissue
- carry messages back and forth between the brain and every other part of the body.
- Endoskeleton
- the internal skeleton
- Adaptive Radiation
- the evolution of many diversely adapted species from a common ancestor upon introduction to various new environmental opportunities and challenges
- Mollusks
- A group of soft bodied organisms that usually have shells, have very developed brains, and are divided into three classes- bivalve (clams), cephalopod (octopi and squid), and gastropod (snails)
- Posterior
- at or near the hind end in quadrupeds or toward the spine in primates
- Bilateral Symmetry
- Characterizing a body form with a central longitudinal plane that divides the body into two equal but opposite halves
- Porifera
- Sponges; sessile; diploblastic; pores; radial symmetry
- Chordates
- an animal phylum that has a notochord, a dorsal hollow nerve cord, and gill slits at some time in its life cycle
- Monophyletic
- ALL descendants came from one common ancestor
- Radial Symmetry
- Characterizing a body shaped like a pie or barrel, with many equal parts radiating outward like the spokes of a wheel; present in cnidarians and echinoderms
- Coelom
- a body cavity completely lined with mesoderm
- Ventral
- toward or on or near the belly (front of a primate or lower surface of a lower animal)
- Mesoderm
- the middle germ layer that develops into muscle and bone and cartilage and blood and connective tissue
- Disruptive Selection
- a descriptive term used to describe changes in population genetics that simultaneously favor individuals at both extremes of the distribution
- Pseudocoelomates
- An animal whose body cavity is not completely lined by mesoderm
- Annelids
- segmented worms
- Exoskeleton
- the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs
- Deuterostomates
- anus first, then mouth
- Endoderm
- The innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract
- Natural Selection
- Genetic change or changes in the frequencies of certain traits in populations due to differential reproductive success between individuals
- Aerobic Respiration
- chemical process where oxygen is used to make energy from carbohydrates (sugars)