Biology

Parapneuroptera

Paraneoptera — the insect superorder containing lice, thrips and true bugs

Parasitism

Parasitism: biological interactions, types, and impacts

Parasitism is a biological relationship in which one organism benefits at the expense of another. This article explains definitions, types, life cycles, ecological roles, human exa

Parasitoid

Parasitoid (insect life strategy)

Parasympathetic nervous system

Parathyroid glands

Paraves

Paraves: the clade linking birds and their closest dinosaur relatives

Parazoa

Parazoa: the basal animal group including sponges and placozoans

Parenthesome

Parietal lobe

Parotoid gland

Parthenogenesis

Parthenogenesis: asexual reproduction by unfertilized eggs

Pasteurella multocida

Pathogen

Pectinase

Pectinina

Pectinina (bivalve suborder)

Pediococcus

Pelvis

Pelvis (human anatomy): structure, function and development

Pelycosaur

Pelycosaurs: early synapsids that preceded therapsids and mammals

Penicillium

Penicillium — overview, biology, uses and significance

Penis

Penis: structure, function, and variation across animals

Peppered moth evolution

Peppered moth evolution: industrial melanism, genetics, and scientific significance

Pepsin

Pepsin: the principal gastric protease

Peptide

Peptide (biochemistry): short amino‑acid chains, structure and uses

Peripheral nervous system

Peristalsis

Peroxisome

Pest (biology)

Pesticide

Petri dish

Petri dish: design, history, and uses in microbiology and education

Phagocyte

Pharmacokinetics

Phenotype

Phenotype — observable characteristics and biological expression of organisms

Pheromone

Phospholipid

Photoreceptor cell

Photosynthesis

Photosynthesis: How Organisms Convert Light into Chemical Energy

Photosynthesis is the process by which plants, algae and some bacteria use sunlight to produce sugars and oxygen from water and carbon dioxide, forming the base of most ecosystems.

Phototroph

Phycology

Phylogeny

Phylogeny: the study and representation of evolutionary relationships

Phylum

Phylum (biology): rank, definition, and role in classifying life

Physiology

Physiology: function, levels, methods, and medical relevance

Pimple

Pineal gland

Pithovirus

Pithovirus — a giant amoeba-infecting virus discovered in Siberian permafrost

Pituitary gland

Pituitary gland: structure, function, development, and clinical relevance

Placenta

The placenta is a temporary organ that develops in the uterus during pregnancy to support the developing fetus by exchanging gases, nutrients, wastes and hormones between mother an

Plankton

Planococcaceae