Ecosystem in the context of Display behaviour

Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis).

Biology examines life across multiple levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including observation, experimentation, and mathematical modeling. Modern biology is grounded in the theory of evolution by natural selection, first articulated by Charles Darwin, and in the molecular understanding of genes encoded in DNA. The discovery of the structure of DNA and advances in molecular genetics have transformed many areas of biology, leading to applications in medicine, agriculture, biotechnology, and environmental science.

Urban areas usually experience the urban heat island (UHI) effect; that is, they are significantly warmer than surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak, under block conditions, noticeably during the summer and winter.The main cause of the UHI effect is from the modification of land surfaces, while waste heat generated by energy usage is a secondary contributor. Urban areas occupy about 0.5% of the Earth's land surface but host more than half of the world's population. As a population center grows, it tends to expand its area and increase its average temperature. The term heat island is also used; the term can be used to refer to any area that is relatively hotter than the surrounding, but generally refers to human-disturbed areas.

Monthly rainfall is greater downwind of cities, partially due to the UHI. Increases in heat within urban centers increases the length of growing seasons, decreases air quality by increasing the production of pollutants such as ozone, and decreases water quality as warmer waters flow into area streams and put stress on their ecosystems.

Human impact on the environment (or anthropogenic environmental impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the needs of society (as in the built environment) is causing severe effects including global warming, environmental degradation (such as ocean acidification), mass extinction and biodiversity loss, ecological crisis, and ecological collapse. Some human activities that cause damage (either directly or indirectly) to the environment on a global scale include population growth, neoliberal economic policies and rapid economic growth, overconsumption, overexploitation, pollution, and deforestation. Some of the problems, including global warming and biodiversity loss, have been proposed as representing catastrophic risks to the survival of the human species.

The term anthropogenic designates an effect or object resulting from human activity. The term was first used in the technical sense by Russian geologist Alexey Pavlov, and it was first used in English by British ecologist Arthur Tansley in reference to human influences on climax plant communities. The atmospheric scientist Paul Crutzen introduced the term "Anthropocene" in the mid-1970s. The term is sometimes used in the context of pollution produced from human activity since the start of the Agricultural Revolution but also applies broadly to all major human impacts on the environment. Many of the actions taken by humans that contribute to a heated environment stem from the burning of fossil fuel from a variety of sources, such as electricity, cars, planes, space heating, manufacturing, or the destruction of forests.

A coast (also called the coastline, shoreline, or seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, such as that caused by waves. The geological composition of rock and soil dictates the type of shore that is created. Earth has about 620,000 km (390,000 mi) of coastline.

Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor ecosystems, such as freshwater or estuarine wetlands, that are important for birds and other terrestrial animals. In wave-protected areas, coasts harbor salt marshes, mangroves, and seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic animals. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals (e.g. mussels, starfish, barnacles) and various kinds of seaweeds.

The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as oceans (in descending order: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Antarctic/Southern Ocean, and the Arctic Ocean), and are themselves mostly divided into seas, gulfs and subsequent bodies of water. The ocean contains 97% of Earth's water and is the primary component of Earth's hydrosphere, acting as a huge reservoir of heat for Earth's energy budget, as well as for its carbon cycle and water cycle, forming the basis for climate and weather patterns worldwide. The ocean is essential to life on Earth, harbouring most of Earth's animals and protist life, originating photosynthesis and therefore Earth's atmospheric oxygen, still supplying half of it.

Ocean scientists split the ocean into vertical and horizontal zones based on physical and biological conditions. Horizontally the ocean covers the oceanic crust, which it shapes. Where the ocean meets dry land it covers relatively shallow continental shelfs, which are part of Earth's continental crust. Human activity is mostly coastal with high negative impacts on marine life. Vertically the pelagic zone is the open ocean's water column from the surface to the ocean floor. The water column is further divided into zones based on depth and the amount of light present. The photic zone starts at the surface and is defined to be "the depth at which light intensity is only 1% of the surface value" (approximately 200 m in the open ocean). This is the zone where photosynthesis can occur. In this process plants and microscopic algae (free-floating phytoplankton) use light, water, carbon dioxide, and nutrients to produce organic matter. As a result, the photic zone is the most biodiverse and the source of the food supply which sustains most of the ocean ecosystem. Light can only penetrate a few hundred more meters; the rest of the deeper ocean is cold and dark (these zones are called mesopelagic and aphotic zones).

Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area. Phytogeography is the branch of biogeography that studies the distribution of plants, Zoogeography is the branch that studies distribution of animals, while Mycogeography is the branch that studies distribution of fungi, such as mushrooms.

Knowledge of spatial variation in the numbers and types of organisms is as vital to us today as it was to our early human ancestors, as we adapt to heterogeneous but geographically predictable environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, taxonomy, geology, physical geography, palaeontology, and climatology.

The Indus (/ˈɪndəs/ IN-dəs) is a transboundary river of Asia and a trans-Himalayan river of South and Central Asia. The 3,180 km (1,980 mi) river rises in western China, flows northwest through the disputed Kashmir region, first through the Indian-administered Ladakh, and then the Pakistani-administered Gilgit-Baltistan, bends sharply to the left after the Nanga Parbat massif, and flows south-by-southwest through Pakistan, before bifurcating and emptying into the Arabian Sea, its main stem located near the port city of Karachi.

The Indus River has a total drainage area of circa 1,120,000 km (430,000 sq mi). Its estimated annual flow is around 175 km/a (5,500 m/s), making it one of the 50 largest rivers in the world in terms of average annual flow. Its left-bank tributary in Ladakh is the Zanskar River, and its left-bank tributary in the plains is the Panjnad River which is formed by the successive confluences of the five Punjab rivers, namely the Chenab, Jhelum, Ravi, Beas, and Sutlej rivers. Its principal right-bank tributaries are the Shyok, Gilgit, Kabul, Kurram, and Gomal rivers. Beginning in a mountain spring and fed with glaciers and rivers in the Himalayan, Karakoram, and Hindu Kush ranges, the river supports the ecosystems of temperate forests, plains, and arid countryside.

Sustainable architecture is architecture that seeks to minimize the negative environmental impact of buildings through improved efficiency and moderation in the use of materials, energy, development space and the ecosystem at large. Sometimes, sustainable architecture will also focus on the social aspect of sustainability as well. Sustainable architecture uses a conscious approach to energy and ecological conservation in the design of the built environment.

The concept of sustainability, or ecological design, ensures that the use of current resources does not adversely affect future society's well-being or render it impossible to obtain resources for other uses in the long term.

Life is matter that has biological processes, such as signaling and the ability to sustain itself. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction. All life over time eventually reaches a state of death, and none is immortal. Many philosophical definitions of living systems have been proposed, such as self-organizing systems. Defining life is further complicated by viruses, which replicate only in host cells, and the possibility of extraterrestrial life, which is likely to be very different from terrestrial life. Life exists all over the Earth in air, water, and soil, with many ecosystems forming the biosphere. Some of these are harsh environments occupied only by extremophiles. The life in a particular ecosystem is called its biota.

Life has been studied since ancient times, with theories such as Empedocles's materialism asserting that it was composed of four eternal elements, and Aristotle's hylomorphism asserting that living things have souls and embody both form and matter. Life originated at least 3.5 billion years ago, resulting in a universal common ancestor. This evolved into all the species that exist now, by way of many extinct species, some of which have left traces as fossils. Attempts to classify living things, too, began with Aristotle. Modern classification began with Carl Linnaeus's system of binomial nomenclature in the 1740s.

In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them underpin biology as a whole. They affect a plethora of species, in all forms of environmental conditions, such as marine or terrestrial animals. Humans can make or change abiotic factors in a species' environment. For instance, fertilizers can affect a snail's habitat, or the greenhouse gases which humans utilize can change marine pH levels.

Abiotic components include physical conditions and non-living resources that affect living organisms in terms of growth, maintenance, and reproduction. Resources are distinguished as substances or objects in the environment required by one organism and consumed or otherwise made unavailable for use by other organisms. Component degradation of a substance occurs by chemical or physical processes, e.g. hydrolysis. All non-living components of an ecosystem, such as atmospheric conditions and water resources, are called abiotic components.

Ecological units refer to specific levels or degrees of organization within ecological systems. The units that are most commonly used and discussed within ecological systems are those at the levels of individuals, populations, communities, and ecosystems. These terms help distinguish between very specific, localized interactions, such as those occurring at the individual or population level, and broader, more complex interactions that occur at the community and ecosystem levels, providing a framework for understanding ecological structure and processes at different scales.

These ecological units are foundational to the field of ecology as they define and identify the key components and relationships within ecological systems at the different levels—providing cohesion in conversation and research. Additionally, these terms and the concept of ecological units as a whole are intertwined in ecological theory, understanding biodiversity, conservation strategies, and more. However, these ecological units have been met with some disagreements over the inconsistencies in the exact terminology and its uses. Arguments over stem from conflicting views from four different areas:

Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from soil by restricting the former term specifically to displaced soil.

Soil consists of a solid collection of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and a liquid phase that holds water and dissolved substances both organic and inorganic, in ionic or in molecular form (the soil solution). Accordingly, soil is a complex three-state system of solids, liquids, and gases. Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness, soil ecologists regard soil as an ecosystem.

Ecology (from Ancient Greek οἶκος (oîkos)  'house' and -λογία (-logía)  'study of') is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history.

Ecology is a branch of biology, and is the study of abundance, biomass, and distribution of organisms in the context of the environment. It encompasses life processes, interactions, and adaptations; movement of materials and energy through living communities; successional development of ecosystems; cooperation, competition, and predation within and between species; and patterns of biodiversity and its effect on ecosystem processes.

Environmental science is an academic field that integrates the physical, biological, and mathematical sciences to study the environment and solve environmental problems. It uses an integrated, quantitative, and interdisciplinary approach to analyze environmental systems and emerged from the fields of natural history and medicine during the Enlightenment. It is considered interdisciplinary because it is an integration of various fields such as: biology, chemistry, physics, geology, engineering, sociology, and ecology.

Environmental science came alive as a substantive, active field of scientific investigation in the 1960s and 1970s driven by, the need for a multi-disciplinary approach to analyze complex environmental problems, the arrival of substantive environmental laws requiring specific environmental protocols of investigation, and the growing public awareness of a need for action in addressing environmental problems. Events that spurred this development included the publication of Rachel Carson's landmark environmental book Silent Spring along with major environmental issues becoming public, such as the 1969 Santa Barbara oil spill, and the Cuyahoga River of Cleveland, Ohio "catching fire", also in 1969.

Marine microorganisms are defined by their habitat as microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism (or microbe) is any microscopic living organism or virus, which is invisibly small to the unaided human eye without magnification. Microorganisms are very diverse. They can be single-celled or multicellular and include bacteria, archaea, viruses, and most protozoa, as well as some fungi, algae, and animals, such as rotifers and copepods. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify viruses as microorganisms, but others consider these as non-living.

Marine microorganisms have been variously estimated to make up between 70 and 90 percent of the biomass in the ocean. Taken together they form the marine microbiome. Over billions of years this microbiome has evolved many life styles and adaptations and come to participate in the global cycling of almost all chemical elements. Microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. They are also responsible for nearly all photosynthesis that occurs in the ocean, as well as the cycling of carbon, nitrogen, phosphorus and other nutrients and trace elements. Marine microorganisms sequester large amounts of carbon and produce much of the world's oxygen.

Marine prokaryotes are marine bacteria and marine archaea. They are defined by their habitat as prokaryotes that live in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. All cellular life forms can be divided into prokaryotes and eukaryotes. Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, whereas prokaryotes are the organisms that do not have a nucleus enclosed within a membrane. The three-domain system of classifying life adds another division: the prokaryotes are divided into two domains of life, the microscopic bacteria and the microscopic archaea, while everything else, the eukaryotes, become the third domain.

Prokaryotes play important roles in ecosystems as decomposers recycling nutrients. Some prokaryotes are pathogenic, causing disease and even death in plants and animals. Marine prokaryotes are responsible for significant levels of the photosynthesis that occurs in the ocean, as well as significant cycling of carbon and other nutrients.