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Plant Printouts
EnchantedLearning.com
Botany and Paleobotany Dictionary
yucca
Plants
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Click on an underlined word for more information on that subject.
If the plant term you are looking for is not in the dictionary, please e-mail us.

O


OMNIVORE

Omnivores are animals that eat both animals and plants.

ORDER

In Linnean classification, an order is a group of related or similar organisms. An order contains one or more families. A group of similar orders forms a class.

ORDOVICIAN PERIOD

(pronounced or-da-VISH-ee-en) The Ordovician Period lasted from 505 to 438 million years ago. Primitive plants appear on land, as do the first corals, primitive fishes, seaweed and fungi. Graptolites, bryozoans, gastropods, bivalves, and echinoids also appear. There were high sea levels at first, then global cooling and glaciation, and extensive volcanism. North America was under shallow seas. The Ordovician ended in huge extinction, probably due to glaciation. The Ordovician was named for an ancient tribe (the Ordovices) that lived in northern Wales.

ORGAN

An organ is a specialized tissue (a group of cells) in multicellular organisms that performs a particular function. For example, the ovary is an organ that produces ovules.

ORGANELLE

An organelle is membrane-bound structure within a plant's cell (and all eukaryotic cells) where specialized metabolic tasks occur. Some organelles include the nucleus, nucleolus, mitochondria, the ER (endoplamic reticulum), and lysosomes.

OSMOSIS

Osmosis is a process in which water moves across a semi-permeable membrane in order to equalize the concentration of the solution on both sides. For example, water will move across a cell membrane from areas of low salinity (a hypotonic solution) to areas of high salinity (a hypertonic solution) to equalize the concentrations (and create two isotonic solutions).

OSMOTIC PRESSURE

Osmotic pressure is a phenomenon in which water exerts pressure against a membrane (when it is bordered by solutions of differing concentrations).

OSMOTIC POTENTIAL

Osmotic potential is the potential of water to move into a region by the process of osmosis, the potential of the water to travel from a hypotonic (low concentration) solution to a hypertonic (high concentration) solution.

OUTCROPPING

An outcropping is a place where the bedrock (the underlying rock) is exposed on the Earth's surface.

OVARY

An ovary is a female reproductive organ in plants that produces ovules.

OVERBURDEN

The overburden is the rock that lies on top of a fossil.

OVULE

An ovule is the female reproductive cell of flowering plants and cone-bearing plants. After the ovule is fertilized by the male pollen, the ovule becomes a seed.
fir
Plant Printouts
EnchantedLearning.com
Botany and Paleobotany Dictionary
yucca
Plants
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Click on an underlined word for more information on that subject.
If the plant term you are looking for is not in the dictionary, please e-mail us.

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