Portal:Biology

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Introduction

A panoramic view from a ridge located between Segla and Hesten mountain summits in the island of Senja, Troms, Norway in 2014
A panoramic view from a ridge located between Segla and Hesten mountain summits in the island of Senja, Troms, Norway in 2014

Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments.

Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations. Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the scientific method to make observations, pose questions, generate hypotheses, perform experiments, and form conclusions about the world around them.

Life on Earth, which emerged more than 3.7 billion years ago, is immensely diverse. Biologists have sought to study and classify the various forms of life, from prokaryotic organisms such as archaea and bacteria to eukaryotic organisms such as protists, fungi, plants, and animals. These various organisms contribute to the biodiversity of an ecosystem, where they play specialized roles in the cycling of nutrients and energy through their biophysical environment. (Full article...)

The eukaryotes (/jˈkærits, -əts/ yoo-KARR-ee-ohts, -⁠əts) constitute the domain of Eukarya or Eukaryota, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, and many unicellular organisms are eukaryotes. They constitute a major group of life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes.

The eukaryotes seemingly emerged within the Asgard archaea, and are closely related to the Heimdallarchaeia. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as flagellated cells. The leading evolutionary theory is they were created by symbiogenesis between an anaerobic Asgard archaean and an aerobic proteobacterium, which formed the mitochondria. A second episode of symbiogenesis with a cyanobacterium created the plants, with chloroplasts. (Full article...)
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Side view of the Yellow-winged Darter (Sympetrum flaveolum)

Major topics

History History of biology | timeline of biology and organic chemistry | history of ecology | history of evolutionary thought | history of geology | history of model organisms | history of molecular biology | history of paleontology
Overview Biology | science | life | properties (adaptationenergy processinggrowthorderregulationreproduction, and response to environment) | hierarchy of life (atommoleculeorganellecelltissueorganorgan systemorganismpopulationcommunityecosystembiosphere) | reductionistic | emergent property | mechanistic | scientific method | theory | law | peer review | biology journals
Chemical basis Matter | elements | compounds | atoms | molecules | chemical bonds | carbon | organic compounds | macromolecules | carbohydrate | protein | protein structure | protein folding | lipid | DNA | RNA
Cells Prokaryote | eukaryote | cell wall | cell membrane | cytoskeleton | mitochondrion | chloroplast | nucleus | endoplasmic reticulum | Golgi apparatus | cell cycle | mitosis | metabolism | cell signaling | protein targeting | metabolism | enzyme | glycolysis | citric acid cycle | electron transport chain | oxidative phosphorylation |photosynthesis |meiosis  | mitosis
Genetics (Intro) Classical genetics | mendelian inheritance | gene | phenotype | genotype | ploidy | alternation of generations | molecular genetics | gene expression | gene regulation | genome | karyotype | DNA replication | transcription | translation | recombination | chromosome | epigenetics | splicing | mutation | genetic fingerprint | chromatin | ecological genetics | population genetics | quantitative genetics
Evolution (Intro)  | omne vivum ex ovo | Natural selection | genetic drift | sexual selection | speciation | mutation | gene flow | evolution of sex | biogeography | cladistics | species | extinction | tree of life | phylogenies | three-domain system
Diversity Bacteria | archaea | plants | angiosperms | fungi | protists | Animals | deuterostome | insects | molluscs | nematodes | parasitism | Primate | mammal | vertebrate | craniata | chordate | viruses
Plant form and function Epidermis | flower | ground tissue  | leaf | phloem | plant stem | root | shoot | vascular plant | vascular tissue | xylem
Animal form and function Tissues | fertilization | embryogenesis | gastrulation | neurulation | organogenesis | differentiation | morphogenesis | metamorphosis | ontogeny  | Development | senescence  | reproduction | oogenesis | spermatogenesis
Ecology Ecosystem | biomass | food chain | indicator species | habitat | species distribution | Gaia theory | metapopulation  | life cycle | Life history | altricial - precocial | sex ratio | altruism | cooperation - foraging | learning | parental care | sexual conflict | territoriality | biosphere | climate change | conservation | biodiversity | nature reserve | edge effect | allee effect | corridor | fragmentation | pollution | invasive species | in situ - ex situ | seedbank
Research methods Laboratory techniques | Genetic engineering | transformation | gel electrophoresis | chromatography | centrifugation | cell culture | DNA sequencing | DNA microarray | green fluorescent protein | vector | enzyme assay | protein purification | Western blot | Northern blot | Southern blot | restriction enzyme | polymerase chain reaction | two-hybrid screening | in vivo - in vitro - in silico | Field techniques | Belt transect | mark and recapture | species discovery curve
Branches Anatomy | biotechnology | botany | cell biology | ecology | evolutionary biology | genetics | marine biology | microbiology | molecular biology | mycology | neuroscience | paleontology | phycology | physiology | protistology | virology | zoology
Awards Nobel Prize in Physiology or Medicine
See also Template:History of biology

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Stephen Jay Gould (/ɡld/; September 10, 1941 – May 20, 2002) was an American paleontologist, evolutionary biologist, and historian of science. He was one of the most influential and widely read authors of popular science of his generation. Gould spent most of his career teaching at Harvard University and working at the American Museum of Natural History in New York. In 1996, Gould was hired as the Vincent Astor Visiting Research Professor of Biology at New York University, after which he divided his time teaching between there and Harvard.

Gould's most significant contribution to evolutionary biology was the theory of punctuated equilibrium developed with Niles Eldredge in 1972. The theory proposes that most evolution is characterized by long periods of evolutionary stability, infrequently punctuated by swift periods of branching speciation. The theory was contrasted against phyletic gradualism, the popular idea that evolutionary change is marked by a pattern of smooth and continuous change in the fossil record. (Full article...)

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