Endoskeleton Definition Endoskeletons are the structures that support and protect an organism’s internal organs and tissues within the interior of the body. Endoskeletons can be complex, shaped and function differently depending on the animal’s requirements. Mineralized tissue in the form of bone and cartilage makes up the endoskeleton of most vertebrates. During embryogenesis, the mesoderm … Read more

Simple Cuboidal Epithelium Definition Simple cuboidal epithelium consists of a monolayer of epithelial cells that appear to be square-shaped in cross section. With large, rounded, centrally located nuclei, all the cells of this epithelium are directly attached to the basement membrane. Types of Simple Cuboidal Epithelia This epithelium can be classified based on the location … Read more

Gymnosperm Definition Gymnosperms are a group of plants which produce seeds that are not contained within an ovary or fruit. The seeds are open to the air and are directly fertilized by pollination. “Gymnosperm”, from the Greek, gymnos, “naked” and sperma, “seed”, develop their seeds on the surface of scales and leaves, which often grow … Read more

Euthymic Definition Euthymic is the state of being in euthymia, which is a relatively neutral mood that is neither extremely happy nor extremely sad. It comes from the Greek words eu, meaning good, and thymos, meaning spirit. It is usually used in the context of mental health, especially when referring to bipolar disorder, which is … Read more

Energy Pyramid Definition An energy pyramid (sometimes called a trophic pyramid or an ecological pyramid) is a graphical representation, showing the flow of energy at each trophic level in an ecosystem. The width of each bar represents the units of energy available within each trophic level; the height is always the same. The flow of … Read more

Chemical Formula Definition Chemical formulas use atomic symbols and numerical subscripts to indicate the number and type of atoms in a molecule. Chemical formulas are simple representations of molecules that exist in three dimensions. Chemical formulas describe substances down to the atoms that make them up. The empirical formula, the molecular formula, and the structural … Read more

Bilateral Symmetry Definition Bilateral symmetry refers to creatures with body forms that are mirror reflections along a midline called the sagittal plane. The internal organs, however, are not necessarily distributed symmetrically. The great majority of animals possess bilateral symmetry; sometimes known as plane symmetry, this is a characteristic that applies to 99% of all creatures, … Read more

What are Mendel’s Laws of Heredity? Mendel’s laws of heredity refer to biological concepts of heredity first uncovered by the Austrian monk Gregor Mendel, who lived in the early 1800s.  Mendel conducted experiments crossing various sizes and colors of pea plants and recording the outcomes of these crosses – revolutionized the understanding of heredity. Taken … Read more