Definitions

Pair bonding The formation of a close and lasting association between male and female animals; used particularly in the cooperative rearing of young.
Paleontology the scientific study of fossils
Palp a fleshy process from the mouthparts, see spiders and insects
Palpigradi microwhip scorpions
Pangea The single, huge landmass during the Permian - Triassic.
Papilla plural = papillae A small, fleshy protuberance on an animal's body (see tardigrada). Papillae often have sensory functions such as detecting food.
Parallel evolution the independent acquisition in 2 or more related descendant species of similar derived character states evolved from a common ancestral condition
Parapodium plural = parapodia A leg-like flap in some worms, used for locomotion or creating a water current.
Parasite An animal that lives on or inside another animal, and feeds on its host, or on food its host has swallowed. Parasites may weaken their host, but usually do not kill them.
Parasitic castration the reproductive death of a host organism resulting from a parasitic infection, e. g. Mermis nigrescens
Parasitic male A dwarf male that lives a parasitic existence attached to the body of its female, usually having well developed reproductive organs, but an otherwise degenerate body form, e. g. Bonella vridis
Parasitism Symbiosis in which members of one species exist at the expense of members of another species, usually without causing their deaths.
Parasitoid A parasite that slowly kills the victim. The death of the victim occurs near the end of the parasite's larval development.
Parasitology the study of parasites and parasitism
Parasocial Bees and wasps. A colony in which all the nest sharing females are of the same generation.
Parthenogenesis reproduction by means of eggs that develop without fertilisation
Pathogenic capable of producing disease
Pauropoda a Class in the phylum Uniramia
Peanut worm an animal in the Phylum Sipuncula
Pearly nautilus Nautiloidea
Pea weevil a beetle in the Bruchidae family
Pectinate comb-like, having comb-like teeth
Pectines a sensory comb-like structure as seen in some scorpions
Pedicel of insects, the slender part of the abdomen best seen in Hymenoptera
Pedicellaria Minute pincer-like organs on the surface of certain echinoderms.
Pedipalps In arachnids the second pair of appendages at the front of the body. They can be used for walking, sperm transfer, or capturing prey, depending on species.
Pelagic living in the upper waters of the open sea
Pentastomida Tongue worms
Pentatomidae Shield bugs
Periodicity the periodic or rhythmic occurrences of an event
Peristalsis waves of contraction of circular and longitudinal muscles passing along a tubular organ (e.g. the gut) having a propulsive effect.
Permeability Having pores or spaces allowing fluid to pass through. The measure of the freedom of entry of new members into a community or society.
Pertubation a disturbance: a departure of a biological system from a steady state
Pesticide a chemical agent that kills insects and other animal pests
Petiolate having a stalk
Petiole A stalk. In Hymenoptera the narrow abdominal segment(s) that form the waist.
Petrification a process of fossilization where the tissues are preserved by impregnation with carbonate or silicate minerals
Phagocytosis the ingestion of solid particulate matter by a cell
Pharynx The first part of the gut from where the gill slits open. The muscular and sometimes eversible first part of the gut.
Phasmida the order of stick and leaf insects
Phenology The study of temporal aspects of recurrent natural phenomena, and their relation to weather and climate, e. g. the first sighting each year of a Bombus terrestris queen in a particular location.
Phenotype the expressed traits of an organism
Pheromone A chemical substance, usually a glandular secretion, which is used in communication within species. One individual releases the material as a signal and another responds after tasting or smelling it.
Phoresy one animal exploiting another by using it as a means of transport, e.g. the mites that hitch a ride on bumblebees
Photic zone The top slice of a body of water where light penetrates sufficiently for photosynthesis to occur
Photoreceptor a cell sensitive to light
Photosynthesis the process whereby plants build up complex organic substances from simple ones using the sun's energy.
Phototaxis A movement away (negative) or towards (positive) light where light is the stimulus.
Phylum one of the major taxonomic divisions of the animal kingdom
Phytophage a plant eater
Pieridae The family of butterflies containing the Whites and Brimstones
Pill bug Actually not a bug at all, but the woodlouse Armadillidium vulgare
Placozoa A phylum of multi-cellular animals
Plankton the small plants and animals living free in the surface waters of lakes and oceans.
Plant secondary compounds They are compounds produced by the plants that have no nutritional value to the particular plant, but often affect the health or welfare of another organism, e.g. a herbivore.
Platyhelminthes Flatworms, flukes and tapeworms
Plecoptera Stoneflies
Plumose feathery - as seen in some insect antennae
Pneumostome the opening to the lung in pulmonate gastropods, most easily seen in slugs
Pogonophora Beard worms
Poikilothermic Animals whose body temperature varies and fluctuates with that of the surrounding environment; cold-blooded.
Pollen The male element of flowering plants. Usually a fine dust produced by the anthers. Pollen is eaten by many insects including bumblebees.
Pollen basket Stiff hairs on the hindmost leg of a female bee arranged so that they form a basket which can be packed with pollen.
Pollination The placement of pollen onto the stigma of a carpel by wind or animal vectors, a prerequisite to fertilisation.
Polyandry mating system of one female with more than one male
Polychaeta bristleworms
Polygamy more than one mate at a time
Polygny A mating system involving one male and many females
Polymorphic A population in which 2 or more morphs are present in readily noticeable frequencies
Polyp a simple animal with upwardly-directed mouth, fringe of tentacles, and a simple gut
Polyphagous feeding on a wide variety of different foods
Polyphyletic Pertaining to a taxon whose members were derived from two or more ancestral forms not common to all members.
Polyplacophora chitons - a class of mollusc
Polyploid having more than 2 sets of homologous chromosomes
Polyzoa a.k.a. Bryozoa
Pond skater Gerridae, a water bug in the Hemiptera
Population A group of individuals of one species that live in a particular geographic area.
Population biology The study of the spatial and temporal distribution of organisms
Population dynamics the study of changes within a population, and the factors causing the changes
Population genetics The scientific study of gene pools and genetic variation in biological populations.
Porifera sponges
Preadaptation A structure that evolves and functions in one environmental context, but can perform additional functions when placed in some new environment.
Posterior the rear or tail end
Potter wasp a wasp in the Eumenidae family
Praying mantis an insect in the Dictyoptera order, a mantid
Predation the consumption of one animal (the prey) by another (the predator)
Predator an animal that preys on other organisms
Prepupa A resting (non-feeding) stage that some insects pass through before forming a pupa.
Priapidula A Phylum of marine worm-like animals
Prey Any animal that is eaten by a predator
Primary consumers Herbivores. Organisms in the trophic level that eat plants and algae.
Primary producers Autotrophs. Photosynthetic and chemosynthetic organisms.
Primary succession A type of ecological succession that occurs in an area where there were originally no organisms, e.g. on newly created volcanic islands.
Primitive ancient; little evolved; of characteristics similar to those possessed by the ancestral types
Primordial primitive, primary, original
Proboscis A trunk-like process, sometimes eversible, and usually arising from the head
Progeny the offspring of a single mating, or of an asexually reproducing individual
Proglottid a compartment of a tapeworm's body
Profitability of a prey item A predator will rank items according to their size and quality, against search/handling time. The predator usually consumes those items that have the highest ratio of size, quality : search, handling time; though it will consume some less profitable items as it samples.
Prokaryote Lacking a discrete nucleus in the cell, e.g. bacteria.
Prokaryotic used of an organism lacking a discrete nucleus separated from the cytoplasm by a membrane, e. g. bacteria
Prolegs the soft, unjointed legs found in some invertebrates, e.g. caterpillars
Promiscuous a mating system where neither sex is restricted to a single mate
Pronotum The upper surface of the front segment of an insect's thorax. It may be enlarged to form a shield over the head as in some beetles.
Prosobranchia a subclass of the Gastropods (snails) that have a horny or calcareous plate called an operculum which is used to close the shell opening
Prosoma The front part of the body in some animals, e.g. spiders, where the head and thorax are fused.
Prothorax The front or first of the three segments of an insect's thorax.
Protist A single-celled organism living in water or moist habitats. The cell is usually relatively large and more complex than bacterial cells. Some use photosynthesis to get their energy; others eat. A typical, much-studied protist is Paramecium.
Proventriculus In insects, a muscular dilation of the foregut armed internally with chitinous teeth
Proximal situated towards, or near the point of attachment
Pseudocoelomates Animals whose body cavity is not completely lined by mesoderm, e.g. Nematoda, Rotifera.
Pterostigma A coloured area near the leading edge of some insect wings, e.g. dragonflies.
Pubescent with short, fine hairs
Pulmonate Having lungs, not gills, e.g. pulmonate snails
Punctuated equilibrium A theory of evolution advocating spurts of relatively rapid change followed by long periods of stasis.
Pupa The inactive instar or stage of the holometabolous insect during which development into adult form is completed.
Puparium the case which houses the pupa
Pupate the process of becoming a pupa
Pupation the formation of a pupa by metamorphosis
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