Adaptation in the context of "Pteropod"

A hunter-gatherer or forager is a human living in a community, or according to an ancestrally derived lifestyle, in which most or all food is obtained by foraging, that is, by gathering food from local naturally occurring sources or by hunting game. This is a common practice among most vertebrates that are omnivores. Hunter-gatherer groups, usually a few dozen people, were and are nomadic or semi-nomadic. Hunter-gatherer societies are contrasted with more sedentary agricultural societies, which rely mainly on cultivating crops and raising domesticated animals for food production.

Hunting and gathering emerged with Homo erectus about 1.8 million years ago and was humanity's original and most enduring successful competitive adaptation in the natural world, occupying at least 90 percent of human (pre)history. Following the invention of agriculture, hunter-gatherers who did not change were displaced or conquered by farming or pastoralist groups in most parts of the world. In Western Eurasia, farming and metallurgical societies gradually replaced hunter-gatherers, but dense forests remained their last refuge until Bronze and Iron Age societies fully overcame them.

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.

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.

Evolutionary biology is a subfield of biology that analyzes the four mechanisms of evolution: natural selection, mutation, genetic drift, and gene flow. The purpose of evolutionary biology is to observe the diversity of life on Earth. The idea of natural selection was first researched by Charles Darwin as he studied bird beaks. The discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology. Huxley was able to take what Charles Darwin discovered and elaborate to build on his understandings.

The investigational range of current research has widened to encompass the genetic architecture of adaptation, molecular evolution, and the different forces that contribute to evolution, such as sexual selection, genetic drift, and biogeography. The newer field of evolutionary developmental biology ("evo-devo") investigates how embryogenesis is controlled, thus yielding a wider synthesis that integrates developmental biology with the fields of study covered by the earlier evolutionary synthesis.

An aquatic animal is any animal, whether vertebrate or invertebrate, that lives in a body of water for all or most of its lifetime. Aquatic animals generally conduct aquatic respiration by extracting dissolved oxygen in water via specialised respiratory organs called gills, through the skin or across enteral mucosae, although some are secondarily aquatic animals (e.g. marine reptiles and marine mammals) evolved from terrestrial ancestors that re-adapted to aquatic environments, in which case they actually use lungs to breathe air and are essentially holding their breath when living in water. Some species of gastropod mollusc, such as the eastern emerald sea slug, are even capable of kleptoplastic photosynthesis via endosymbiosis with ingested yellow-green algae.

Almost all aquatic animals reproduce in water, either oviparously or viviparously, and many species routinely migrate between different water bodies during their life cycle. Some animals have fully aquatic life stages (typically as eggs and larvae), while as adults they become terrestrial or semi-aquatic after undergoing metamorphosis. Such examples include amphibians such as frogs, many flying insects such as mosquitoes, mayflies, dragonflies, damselflies and caddisflies, as well as some species of cephalopod molluscs such as the algae octopus (whose larvae are completely planktonic, but adults are highly terrestrial).

A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. While each plant or crop has a specific growing season that depends on its genetic adaptation, growing seasons can generally be grouped into macro-environmental classes.

Axial tilt of the Earth inherently affect growing seasons across the globe.

Climate change adaptation is the process of adjusting to the effects of climate change, both current and anticipated. Adaptation aims to moderate or avoid harm for people, and is usually done alongside climate change mitigation. It also aims to exploit opportunities. Adaptation can involve interventions to help natural systems cope with changes.

Adaptation can help manage impacts and risks to people and nature. The four types of adaptation actions are infrastructural, institutional, behavioural and nature-based options. Some examples are building seawalls or inland flood defenses, providing new insurance schemes, changing crop planting times or varieties, and installing green roofs or green spaces. Adaptation can be reactive (responding to climate impacts as they happen) or proactive (taking steps in anticipation of future climate change).

Systems theory is the transdisciplinary study of systems, i.e. cohesive groups of interrelated, interdependent components that can be natural or artificial. Every system has causal boundaries, is influenced by its context, defined by its structure, function and role, and expressed through its relations with other systems. A system is "more than the sum of its parts" when it expresses synergy or emergent behavior.

Changing one component of a system may affect other components or the whole system. It may be possible to predict these changes in patterns of behavior. For systems that learn and adapt, the growth and the degree of adaptation depend upon how well the system is engaged with its environment and other contexts influencing its organization. Some systems support other systems, maintaining the other system to prevent failure. The goals of systems theory are to model a system's dynamics, constraints, conditions, and relations; and to elucidate principles (such as purpose, measure, methods, tools) that can be discerned and applied to other systems at every level of nesting, and in a wide range of fields for achieving optimized equifinality.

Cyanobacteria (/saɪˌænoʊbækˈtɪəriə/ sy-AN-oh-bak-TEER-ee-ə) are a group of autotrophic gram-negative bacteria of the phylum Cyanobacteriota that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" (from Ancient Greek κύανος (kúanos) 'blue') refers to their bluish green (cyan) color, which forms the basis of cyanobacteria's informal common name, blue-green algae.

Cyanobacteria are probably the most numerous taxon to have ever existed on Earth and the first organisms known to have produced oxygen, having appeared in the middle Archean eon and apparently originated in a freshwater or terrestrial environment. Their photopigments can absorb the red- and blue-spectrum frequencies of sunlight (thus reflecting a greenish color) to split water molecules into hydrogen ions and oxygen. The hydrogen ions are used to react with carbon dioxide to produce complex organic compounds such as carbohydrates (a process known as carbon fixation), and the oxygen is released as a byproduct. By continuously producing and releasing oxygen over billions of years, cyanobacteria are thought to have converted the early Earth's anoxic, weakly reducing prebiotic atmosphere, into an oxidizing one with free gaseous oxygen (which previously would have been immediately removed by various surface reductants), resulting in the Great Oxidation Event and the "rusting of the Earth" during the early Proterozoic, dramatically changing the composition of life forms on Earth. The subsequent adaptation of early single-celled organisms to survive in oxygenous environments likely led to endosymbiosis between anaerobes and aerobes, and hence the evolution of eukaryotes during the Paleoproterozoic.