| oceanic crust |
Crust that underlies the oceans
(excluding continental shelves); it is 5–7 km
thick and consists of basalt and gabbro |
|
| ocelli |
Simple eyes found on many invertebrates. Their function is to detect light and movement, but not shape or form. They are usually found in clusters of 4 - 6 |
|
| oestridae |
family of flies and larvae which lay eggs on the eyes or in the nasal passages of animals |
|
| oestrus |
the period when a female will mate for the purpose of fertilisation |
|
| olfactory |
pertaining to the sense of smell |
|
| oligarchy |
a social system dominated by several large males e.g. a baboon troop |
|
| omasum |
the third compartment of a ruminant stomach. It is a muscular segment that mixes food mechanically |
|
| omnivore |
an organism showing tendencies to eat both plant and animal matter |
|
| oocysts |
the infective spore stage in the life cycle of protozoa |
|
| ootheca |
A packet of invertebrate eggs. Usually with reference ti insects |
|
| organic |
once living or alive |
|
| ornithischia |
Herbivorous branch of the two great
dinosaur lineages, possessing a four-pronged
(tetra-radiate) pelvic structure, and including
such well-known forms as Stegosaurus,
Iguanodon, Triceratops, Parasaurolophus, etc. |
|
| orthognathous |
spiders that actively move around hunting. They can but do not spin webs for prey capture |
|
| osmosis |
the movement of a liquid across a selectively permeable membrane |
|
| osteophagia |
the practice of herbivores consuming bones |
|
| osteophagy |
the practice of eating bones, where the behaviour is not common. E.g. antelope eating bones |
|
| oviduct |
a portion of the female reproductive system |
|
| oviparous |
egg laying |
|
| ovipositor |
an anterior (rear) appendage of female Arthropoda that is used to lay eggs into exact locations. It may be modified into a stinging apparatus e.g. wasps |
|
| ovoviviparous |
refers to species (mostly reptiles)that incubate their eggs internally. Their offspring hatch from these internal eggs and then emerge from the cloaca giving the false impression that they give birth to live young. Snake examples include Puff Adder and Rinkhals |
|
| oxidation |
when oxygen combines with a metallic substance in a chemical reaction |
|
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