Plant Printouts

EnchantedLearning.com Botany and Paleobotany Dictionary

Plants

DATING FOSSILS Dating a fossil is determining when that organism was alive. Paleontologists use many ways of dating individual fossils in geologic time, including stratigraphy, observations of the fluctuations of the Earth's magnetic field, radioisotope-dating, and looking at nearby index fossils.	DECIDUOUS Deciduous plants lose their leaves seasonally, usually for the dry season. Some deciduous plants include ash, beech, hickory, maple, and oak.	DECOMPOSER Decomposers are organisms like fungi and some bacteria that break down and digest the remains of organisms.
DECOMPOSITION Decomposition is the decay or breakdown of things into more basic elements. For example, after a plant dies, it decomposes into organic nutrients.	DEFORESTATION Deforestation is the loss of forest. Deforestation has many causes, including man's cutting down trees, forest fires, severe drought, changes in sea level, disease, etc.	DEHISCENCE Dehiscence is the opening or splitting of a structure on some plants in order to release seeds or pollen grains.
DEHISCENT FRUIT A dehiscent fruit splits open when it is maturite, causing the dispersal of its seeds. Some dehiscent fruits include cotton, poppy, peanuts, milkweed, magnolia, and all beans.	DEHYDRATE To dehydrate is to lose a lot of water. Plants can become dehydrated in dry, hot weather.	DENDROCHRONOLOGY Dendrochronology is the science in which tree rings are studied to determine conditions in the past.
DENDROCLIMATOLOGY Dendroclimatology is the science in which tree rings are studied to determine climate changes in the past.	DESERT A desert is a very dry area that receives less than 10 inches (25 cm) of rainfall each year. Desert organisms have adapted to life with little water.	DETRIVORE A detrivore (or detritus feeder) is an organism that eats the dead remains of other organisms (detritus). Examples of detrivores include some bacteria and fungi.
DIASPORE A diaspore (also called a disseminule) is a part of a plant that is separated from the plant and dispersed (sent or taken away from the plant) for reproduction. Diaspora include seeds, fruits, and spores.	DICHOTOMOUS KEY A dichotomous key is a method for determining the identity of sometihing (like a butterfly, a plant, or a rock) by going through a series of choices that lead the user to the correct name of the item. At each step of the process, the user is given two choices; each alternative leads to another questions until the identification is completed. For example, a question in a dichotomous key for trees might be something like, "Does it have flat or needle-like leaves?" Dichotomous means "divided in two parts".	DICHOTOMOUS VENATION Dichotomous venation is a pattern of leaf veins in which the veins branch in two over and over again. Ferns are dichotomousy veined. A few angiosperms and gymnosperms (like gingkos) have dichotomous venation.
DICOT A dicot (Class Magnoliopsida) is a type of flowering plant (an angiosperm) whose seed has two embryonic leaves (cotyledons). The leaf veins are usually net-like (and not parallel). Taproots are often present. Beans and peas are examples of dicots.	DICTYOSTELE A dictyostele is a siphonostele (a cylinder of vascular tissue) that has two or more overlapping leaf gaps (as in ferns). It is a divided stele located in the outer cortex (instead of in the center of the stem). Dictyosteles are composed of individual vascular bundles.	DIMORPHISM Dimorphism means having two forms. It usually means that an organism has two different types, for example, males and females of some species look different, and are said to be sexually dimorphic.
DIOECIOUS A dioecious plant has the male and female flowers on different plants. For example, date trees are dioecious. (Compare with monoecious.)	DIPLOID A diploid cell has the same number of chromosomes that most other cells of that organism have (except the gametes, like the sperm and the egg, which are haploid).	DIRT Dirt is another name for soil. Soil is a natural, constantly-changing substance that is made up of minerals, organic materials, and living organisms. Plants grow in soil.
DISPERSAL Dispersal is the process in which an organism spreads out geographically. Seeds are dispersed by the winds and by animals.	DISPERSERS Dispersers are animals that spread plant seeds. Some dispersers include birds, insects, bats, and furry animals like monkeys.	DISSEMINULE A disseminule (also called a diaspore) is a part of a plant that is separated from the plant and dispersed (sent or taken away from the plant) for reproduction. Dissemules include seeds, fruits, and spores.
DNA DNA (short for deoxyribonucleic acid) is a complex organic molecule that carries the genetic information of an organism. DNA is the primary constituent of chromosomes. DNA is made up of two strands of nucleotides arranged in a double helix; each nucleotide contains a nucleobase—adenine, cytosine, guanine, or thymine. DNA's chemical instructions are carried throughout the cell by a related kind of molecule, RNA.	DOGGER EPOCH The Dogger epoch was the middle part of the Jurassic period, about 180 to 159 million years ago.	DOMINANT The dominant plant is the most adundant species in an area, for example, pine trees are dominant in a pine forest.
DORMANCY Dormancy is a period in which a plant has no active growth in response to harsh environmental conditions (like droughts or cold seasons).	DOUBLE COMPOUND LEAF A double compound leaf is a leaf in which each leaflet of a compound leaf is made up of secondary leaflets.	DRIP TIP The drip tip is the long, sharply-pointed tip on some rainforest plant leaves that allows water to flow quickly off the leaf surface. In the rainforest, many leaves have a drip tip. Without it, water would build up on the leaf.

Plant Printouts

EnchantedLearning.com Botany and Paleobotany Dictionary

Plants

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