Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
Insects or Insecta are hexapod invertebrates and the largest group within the arthropod phylum. Definitions and circumscriptions vary; as used here, the term Insecta is synonymous with Ectognatha. Insects have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes and one pair of antennae. Insects are the most diverse group of animals; the total number of extant species is estimated at between ten million. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans. Nearly all insects hatch from eggs. Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts; the immature stages differ from the adults in structure and habitat, can include a passive pupal stage in those groups that undergo four-stage metamorphosis. Insects that undergo three-stage metamorphosis lack a pupal stage and adults develop through a series of nymphal stages.
The higher level relationship of the insects is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm; the most diverse insect groups appear to have coevolved with flowering plants. Adult insects move about by walking, flying, or sometimes swimming; as it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles, composed of the front & rear on one side with the middle on the other side. Insects are the only invertebrates to have evolved flight, all flying insects derive from one common ancestor. Many insects spend at least part of their lives under water, with larval adaptations that include gills, some adult insects are aquatic and have adaptations for swimming; some species, such as water striders, are capable of walking on the surface of water. Insects are solitary, but some, such as certain bees and termites, are social and live in large, well-organized colonies.
Some insects, such as earwigs, show maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances. Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyrid beetles communicate with light. Humans regard certain insects as pests, attempt to control them using insecticides, a host of other techniques; some insects damage crops by feeding on sap, fruits, or wood. Some species are parasitic, may vector diseases; some insects perform complex ecological roles. Insect pollinators are essential to the life cycle of many flowering plant species on which most organisms, including humans, are at least dependent. Many insects are considered ecologically beneficial as predators and a few provide direct economic benefit. Silkworms produce silk and honey bees produce honey and both have been domesticated by humans.
Insects are consumed as food in 80% of the world's nations, by people in 3000 ethnic groups. Human activities have effects on insect biodiversity; the word "insect" comes from the Latin word insectum, meaning "with a notched or divided body", or "cut into", from the neuter singular perfect passive participle of insectare, "to cut into, to cut up", from in- "into" and secare "to cut". A calque of Greek ἔντομον, "cut into sections", Pliny the Elder introduced the Latin designation as a loan-translation of the Greek word ἔντομος or "insect", Aristotle's term for this class of life in reference to their "notched" bodies. "Insect" first appears documented in English in 1601 in Holland's translation of Pliny. Translations of Aristotle's term form the usual word for "insect" in Welsh, Serbo-Croatian, etc; the precise definition of the taxon Insecta and the equivalent English name "insect" varies. In the broadest circumscription, Insecta sensu lato consists of all hexapods. Traditionally, insects defined in this way were divided into "Apterygota" —the wingless insects—and Pterygota—the winged insects.
However, modern phylogenetic studies have shown that "Apterygota" is not monophyletic, so does not form a good taxon. A narrower circumscription restricts insects to those hexapods with external mouthparts, comprises only the last three groups in the table. In this sense, Insecta sensu stricto is equivalent to Ectognatha. In the narrowest circumscription, insects are restricted to hexapods that are either winged or descended from winged ancestors. Insecta sensu strictissimo is equivalent to Pterygota. For the purposes of this article, the middle definition is used; the evolutionary relationship of insects to other animal groups remains unclear. Although traditionally grouped with millipedes and centiped
Institute of Food and Agricultural Sciences
The Institute of Food and Agricultural Sciences is an agriculture, life science and invasive species research facility in Florida affiliated with University of Florida. It is a partnership between federal and county governments that includes an extension office in each of Florida's 67 counties, 13 research and education centers, several demonstration sites, the University of Florida College of Agricultural and Life Sciences, the Center for Tropical Agriculture, portions of the University of Florida College of Veterinary Medicine, the Florida Sea Grant program, the International Program for Food and Natural Resources. IFAS research and development covers natural resource industries that have a $101 billion annual impact; the program is ranked #1 in the nation by the NSF. Because of this mission and the diversity of Florida’s climate and agricultural commodities, IFAS has facilities located throughout Florida. Starting June 1, 2010 IFAS will be under the leadership of Dr. Jack Payne, named Senior Vice President for agriculture and natural resources for the University of Florida on February 26, 2010.
The UF/IFAS research mission is to invent and develop knowledge to enhance the agriculture and natural resources of Florida. Faculty members pursue fundamental and applied research that furthers understanding of natural and human systems. Research is supported by state and federally appropriated funds and supplemented by grants and contracts; the Institute of Food and Agricultural Sciences was awarded $166 million in annual research expenditures in sponsored research for 2018. The Florida Agricultural Experiment Station administers and supports research programs in UF/IFAS; the research program was created in 1887 by federal legislation known as the Hatch Act, a follow-up to the 1862 Morrill Act that established U. S. land-grant universities. The research programs support 350 full-time equivalent faculty members in 16 academic departments on UF’s Gainesville campus and at 13 research and education centers around the state. Most IFAS research can be accessed via the searchable UF/IFAS Electronic Data Information Source.
IFAS supports one of the nation's largest collections of food safety facilities and faculty in the country, is integral in maintaining the National Food Safety Database. Along with researchers specializing in controlling spread of pathogens such as E. coli and Salmonella, IFAS has uniquely specialized research programs dedicated to the science of food packaging and a Center for Food Distribution and Retailing. IFAS microbiologist Lonnie Ingram holds several patents on a unique way to produce cellulosic ethanol using a genetically engineered form of E. coli to break down biomass. A cellulosic ethanol power plant utilizing this method began construction in Louisiana in 2007. Florida is the state most indundated with invasive animal species. Nearly 85 percent of new plants entering the country travel through Miami; as such, much of the UF Department of Entomology and Nematology as well as a Center for Aquatic and Invasive Plants have been dedicated to fighting this problem. IFAS is part of the University of Florida's Emerging Pathogens Institute.
IFAS has been involved in dealing with emerging food safety issues such the recent surge of E. coli and Salmonella infections due to bacteria on fresh produce served at restaurants and grocery stores. Established in 1917 IFAS' Citrus Research and Education Center is the largest citrus research institution in existence with more than 40 laboratories, 250 employees, over 220 acres of groves and greenhouses. Dr. Gary Butcher is recognized as one of the foremost experts on poultry pathogens in the United States; the 1914 Smith-Lever Act provided federal support for land-grant institutions to offer educational programs to enhance the application of useful and practical information beyond their campuses through cooperative extension efforts with states and local communities. UF/IFAS Extension provides Floridians with lifelong learning programs in cooperation with county government, the United States Department of Agriculture, Florida A&M; the wide breadth of educational programming offered in each county responds to the local needs of residents, regulatory agencies, community organizations, industry.
Programs promote sustainable agriculture, teaching environmental stewardship, understanding of food nutrition and safety and parenting skills, providing leadership for youth development through programs like 4-H. By partnering with local government, advisory committees, concerned citizens, commodity groups and the youth of Florida, UF/IFAS Extension creates an important link between the public and research conducted on campus and at 13 research and education centers. Solutions for Your Life is the web site of University of Florida Extension, making IFAS faculty expertise available online under such categories as lawn and garden care, family life and consumer choices, community development, the environment, youth development; the web site is focused on providing relevant solutions. In addition to facilities on the University of Florida campus and Extension offices in each of Florida’s 67 counties, IFAS has 1,255 buildings, 3,190,448 square feet gross, 16,591 acres throughout the state; these facilities are used for teaching and demonstration: 16 on-campus academic departments 13 Research & Education Centers located throughout the state Florida Cooperative Extension Service offices in all 67 counties 6 Research sites/demonstration
Flies are insects with a pair of functional wings for flight and a pair of vestigial hindwings called halteres for balance. They are classified as an order called Diptera, that name being derived from the Greek δι- di- "two", πτερόν pteron "wings"; the order Diptera is divided with about 110 families divided between them. The earliest fly fossils found so far are from the Triassic, about 240 million years ago. Many insects, such as the butterfly, contain the word are not Dipterans; the word "fly" is sometimes used colloquially and non-scientifically as a name for any small flying insect: the term "true fly" is sometimes invoked to make clear the insect being referenced is a Dipteran. Flies have a mobile head, with a pair of large compound eyes, mouthparts designed for piercing and sucking, or for lapping and sucking in the other groups; the suborder Nematocera have long antennae. Flies have only a single pair of wings to fly; the hindwings evolved into advanced mechanosensory organs, which act as high-speed sensors of rotational movement and allow them to perform advanced aerobatics.
Claws and pads on their feet enable them to cling to smooth surfaces. The life cycle of flies consists of the eggs, larva and the adult. Flies undergo complete metamorphosis; the pupa in higher dipterans is a tough capsule. Flies have short lives: for example, the adult housefly lives about a month; the source of nutrition for adult flies is liquified food, including nectar. Flies are of human importance, they are important pollinators, second only to their Hymenopteran relatives. They may have been responsible for the first plant pollination in the Triassic. Mosquitoes are vectors for malaria, West Nile fever, yellow fever and other infectious diseases. Flies can be annoyances in some parts of the world where they can occur in large numbers and settling on the skin or eyes to bite or seek fluids. Larger flies such as tsetse flies and screwworms cause significant economic harm to cattle. Blowfly larvae, known as gentles, other dipteran larvae, known more as maggots, are used as fishing bait, as food for carnivorous animals, in medicine for debridement to clean wounds.
Fruit flies are used as model organisms in research. In culture, the subject of flies appears in religion, literature and music. Dipterans are insects that undergo radical metamorphosis, they belong to the Mecopterida, alongside the Mecoptera, Siphonaptera and Trichoptera. The possession of a single pair of wings distinguishes most true flies from other insects with "fly" in their names. However, some true flies such as Hippoboscidae have become secondarily wingless; the cladogram represents the current consensus view. The first true dipterans known are from the Middle Triassic around 240 million years ago, they became widespread during the Middle and Late Triassic. Phylogenetic analysis of times of divergence suggests that dipterans originated in the Permian, some 260 million years ago. Modern flowering plants did not appear until the Cretaceous, so the original dipterans must have had a different source of nutrition other than nectar. Based on the attraction of many modern fly groups to shiny droplets, it has been suggested that they may have fed on honeydew produced by sap-sucking bugs which were abundant at the time, dipteran mouthparts are well-adapted to softening and lapping up the crusted residues.
The basal clades in the Diptera include the enigmatic Nymphomyiidae. Three episodes of evolutionary radiation are thought to have occurred based on the fossil record. Many new species of lower Diptera developed in the Triassic, about 220 million years ago. Many lower Brachycera appeared in the Jurassic, some 180 million years ago. A third radiation took place among the Schizophora at the start of the Paleogene, 66 million years ago; the phylogenetic position of Diptera has been controversial. The monophyly of holometabolous insects has long been accepted, with the main orders being established as Lepidoptera, Coleoptera and Diptera, it is the relationships between these groups which has caused difficulties. Diptera is thought to be a member of Mecopterida, along with Lepidoptera, Siphonaptera and Strepsiptera. Diptera has been grouped with Siphonaptera and Mecoptera in the Antliophora, but this has not been confirmed by molecular studies. Diptera were traditionally broken down into two suborders and Brachycera, distinguished by the differences in antennae.
The Nematocera are recognized by their elongated bodies and many-segmented feathery antennae as represented by mosquitoes and crane flies. The Brachycera have rounder bodies and much sh
Carl Linnaeus known after his ennoblement as Carl von Linné, was a Swedish botanist and zoologist who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin, his name is rendered in Latin as Carolus Linnæus. Linnaeus was born in the countryside of Småland in southern Sweden, he received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and published the first edition of his Systema Naturae in the Netherlands, he returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect and classify animals and minerals, while publishing several volumes, he was one of the most acclaimed scientists in Europe at the time of his death. Philosopher Jean-Jacques Rousseau sent him the message: "Tell him I know no greater man on earth."
Johann Wolfgang von Goethe wrote: "With the exception of Shakespeare and Spinoza, I know no one among the no longer living who has influenced me more strongly." Swedish author August Strindberg wrote: "Linnaeus was in reality a poet who happened to become a naturalist." Linnaeus has been called Princeps botanicorum and "The Pliny of the North". He is considered as one of the founders of modern ecology. In botany and zoology, the abbreviation L. is used to indicate Linnaeus as the authority for a species' name. In older publications, the abbreviation "Linn." is found. Linnaeus's remains comprise the type specimen for the species Homo sapiens following the International Code of Zoological Nomenclature, since the sole specimen that he is known to have examined was himself. Linnaeus was born in the village of Råshult in Småland, Sweden, on 23 May 1707, he was the first child of Christina Brodersonia. His siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, Emerentia Linnæa, his father taught him Latin as a small child.
One of a long line of peasants and priests, Nils was an amateur botanist, a Lutheran minister, the curate of the small village of Stenbrohult in Småland. Christina was the daughter of the rector of Samuel Brodersonius. A year after Linnaeus's birth, his grandfather Samuel Brodersonius died, his father Nils became the rector of Stenbrohult; the family moved into the rectory from the curate's house. In his early years, Linnaeus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and showed flowers to Linnaeus and told him their names. Soon Linnaeus was given his own patch of earth. Carl's father was the first in his ancestry to adopt a permanent surname. Before that, ancestors had used the patronymic naming system of Scandinavian countries: his father was named Ingemarsson after his father Ingemar Bengtsson; when Nils was admitted to the University of Lund, he had to take on a family name. He adopted the Latinate name Linnæus after a giant linden tree, lind in Swedish, that grew on the family homestead.
This name was spelled with the æ ligature. When Carl was born, he was named Carl Linnæus, with his father's family name; the son always spelled it with the æ ligature, both in handwritten documents and in publications. Carl's patronymic would have been Nilsson, as in Carl Nilsson Linnæus. Linnaeus's father began teaching him basic Latin and geography at an early age; when Linnaeus was seven, Nils decided to hire a tutor for him. The parents picked a son of a local yeoman. Linnaeus did not like him, writing in his autobiography that Telander "was better calculated to extinguish a child's talents than develop them". Two years after his tutoring had begun, he was sent to the Lower Grammar School at Växjö in 1717. Linnaeus studied going to the countryside to look for plants, he reached the last year of the Lower School when he was fifteen, taught by the headmaster, Daniel Lannerus, interested in botany. Lannerus gave him the run of his garden, he introduced him to Johan Rothman, the state doctor of Småland and a teacher at Katedralskolan in Växjö.
A botanist, Rothman broadened Linnaeus's interest in botany and helped him develop an interest in medicine. By the age of 17, Linnaeus had become well acquainted with the existing botanical literature, he remarks in his journal that he "read day and night, knowing like the back of my hand, Arvidh Månsson's Rydaholm Book of Herbs, Tillandz's Flora Åboensis, Palmberg's Serta Florea Suecana, Bromelii Chloros Gothica and Rudbeckii Hortus Upsaliensis...."Linnaeus entered the Växjö Katedralskola in 1724, where he studied Greek, Hebrew and mathematics, a curriculum designed for boys preparing for the priesthood. In the last year at the gymnasium, Linnaeus's father visited to ask the professors how his son's studies were progressing. Rothman believed otherwise; the doctor offered to have Linnaeus live with his family in Växjö and to teach him physiology and botany. Nils accepted this offer. Rothman showed Linnaeus that botany was a serious sub
Ontario is one of the 13 provinces and territories of Canada and is located in east-central Canada. It is Canada's most populous province accounting for 38.3 percent of the country's population, is the second-largest province in total area. Ontario is fourth-largest jurisdiction in total area when the territories of the Northwest Territories and Nunavut are included, it is home to the nation's capital city and the nation's most populous city, Ontario's provincial capital. Ontario is bordered by the province of Manitoba to the west, Hudson Bay and James Bay to the north, Quebec to the east and northeast, to the south by the U. S. states of Minnesota, Ohio and New York. All of Ontario's 2,700 km border with the United States follows inland waterways: from the west at Lake of the Woods, eastward along the major rivers and lakes of the Great Lakes/Saint Lawrence River drainage system; these are the Rainy River, the Pigeon River, Lake Superior, the St. Marys River, Lake Huron, the St. Clair River, Lake St. Clair, the Detroit River, Lake Erie, the Niagara River, Lake Ontario and along the St. Lawrence River from Kingston, Ontario, to the Quebec boundary just east of Cornwall, Ontario.
There is only about 1 km of land border made up of portages including Height of Land Portage on the Minnesota border. Ontario is sometimes conceptually divided into Northern Ontario and Southern Ontario; the great majority of Ontario's population and arable land is in the south. In contrast, the larger, northern part of Ontario is sparsely populated with cold winters and heavy forestation; the province is named after Lake Ontario, a term thought to be derived from Ontarí:io, a Huron word meaning "great lake", or skanadario, which means "beautiful water" in the Iroquoian languages. Ontario has about 250,000 freshwater lakes; the province consists of three main geographical regions: The thinly populated Canadian Shield in the northwestern and central portions, which comprises over half the land area of Ontario. Although this area does not support agriculture, it is rich in minerals and in part covered by the Central and Midwestern Canadian Shield forests, studded with lakes and rivers. Northern Ontario is subdivided into two sub-regions: Northeastern Ontario.
The unpopulated Hudson Bay Lowlands in the extreme north and northeast swampy and sparsely forested. Southern Ontario, further sub-divided into four regions. Despite the absence of any mountainous terrain in the province, there are large areas of uplands within the Canadian Shield which traverses the province from northwest to southeast and above the Niagara Escarpment which crosses the south; the highest point is Ishpatina Ridge at 693 metres above sea level in Temagami, Northeastern Ontario. In the south, elevations of over 500 m are surpassed near Collingwood, above the Blue Mountains in the Dundalk Highlands and in hilltops near the Madawaska River in Renfrew County; the Carolinian forest zone covers most of the southwestern region of the province. The temperate and fertile Great Lakes-Saint Lawrence Valley in the south is part of the Eastern Great Lakes lowland forests ecoregion where the forest has now been replaced by agriculture and urban development. A well-known geographic feature is part of the Niagara Escarpment.
The Saint Lawrence Seaway allows navigation to and from the Atlantic Ocean as far inland as Thunder Bay in Northwestern Ontario. Northern Ontario occupies 87 percent of the surface area of the province. Point Pelee is a peninsula of Lake Erie in southwestern Ontario, the southernmost extent of Canada's mainland. Pelee Island and Middle Island in Lake Erie extend farther. All are south of 42°N – farther south than the northern border of California; the climate of Ontario varies by location. It is affected by three air sources: cold, arctic air from the north; the effects of these major air masses on temperature and precipitation depend on latitude, proximity to major bodies of water and to a small extent, terrain relief. In general, most of Ontario's climate is classified as humid continental. Ontario has three main climatic regions; the surrounding Great Lakes influence the climatic region of southern Ontario. During the fall and winter months, heat stored from the lakes is released, moderating the climate near the shores of the lakes.
This gives some parts of southern Ontario milder winters than mid-continental areas at lower latitudes. Parts of Southwestern Ontario have a moderate humid continental climate, similar to that of the inland Mid-Atlantic states and the Great Lakes portion of the Midwestern United States; the region has warm to cold winters. Annual precipitation is well distributed throughout the year. Most of this region lies in the lee of the Great Lakes. In December 2010, the snowbelt set a new record when it was h
Acer is a genus of trees and shrubs known as maple. The genus is placed in the family Sapindaceae. There are 128 species, most of which are native to Asia, with a number appearing in Europe, northern Africa, North America. Only one species, Acer laurinum, extends to the Southern Hemisphere; the type species of the genus is the sycamore maple, Acer pseudoplatanus, the most common maple species in Europe. The maples have recognizable palmate leaves and distinctive winged fruits; the closest relatives of the maples are the horse chestnuts. Most maples are trees growing to a height of 10–45 m. Others are shrubs less than 10 meters tall with a number of small trunks originating at ground level. Most species are deciduous, many are renowned for their autumn leaf colour, but a few in southern Asia and the Mediterranean region are evergreen. Most are shade-tolerant when young and are riparian, understory, or pioneer species rather than climax overstory trees. There are a few exceptions such as sugar maple.
Many of the root systems are dense and fibrous, inhibiting the growth of other vegetation underneath them. A few species, notably Acer cappadocicum produce root sprouts, which can develop into clonal colonies. Maples are distinguished by opposite leaf arrangement; the leaves in most species are palmate veined and lobed, with 3 to 9 veins each leading to a lobe, one of, central or apical. A small number of species differ in having palmate compound, pinnate compound, pinnate veined or unlobed leaves. Several species, including Acer griseum, Acer mandshuricum, Acer maximowiczianum and Acer triflorum, have trifoliate leaves. One species, Acer negundo, has pinnately compound leaves that may be trifoliate or may have five, seven, or nine leaflets. A few, such as Acer laevigatum and Acer carpinifolium, have pinnately veined simple leaves. Maple species, such as Acer rubrum, may be dioecious or polygamodioecious; the flowers are regular and borne in racemes, corymbs, or umbels. They have four or five sepals, four or five petals about 1 – 6 mm long, four to ten stamens about 6 – 10 mm long, two pistils or a pistil with two styles.
The ovary is superior and has two carpels, whose wings elongate the flowers, making it easy to tell which flowers are female. Maples flower in late winter or early spring, in most species with or just after the appearance of the leaves, but in some before the trees leaf out. Maple flowers are green, orange or red. Though individually small, the effect of an entire tree in flower can be striking in several species; some maples are an early spring source of nectar for bees. The distinctive fruits are called samaras, "maple keys", "helicopters", "whirlybirds" or "polynoses"; these seeds occur in distinctive pairs each containing one seed enclosed in a "nutlet" attached to a flattened wing of fibrous, papery tissue. They are shaped to carry the seeds a considerable distance on the wind. People call them "helicopters" due to the way that they spin as they fall. During World War II, the US Army developed a special air drop supply carrier that could carry up to 65 pounds of supplies and was based on the Maple seed.
Seed maturation is in a few weeks to six months after flowering, with seed dispersal shortly after maturity. However, one tree can release hundreds of thousands of seeds at a time. Depending on the species, the seeds can be green to orange and big with thicker seed pods; the green seeds are released in pairs, sometimes with the stems still connected. The yellow seeds are released individually and always without the stems. Most species require stratification in order to germinate, some seeds can remain dormant in the soil for several years before germinating; the genus Acer together with genus Dipteronia are either classified in a family of their own, the Aceraceae, or else classified as members of the family Sapindaceae. Recent classifications, including the Angiosperm Phylogeny Group system, favour inclusion in Sapindaceae; when put in family Sapindaceae, genus Acer is put in subfamily Hippocastanoideae. The genus is subdivided by its morphology into a multitude of subsections. Fifty-four species of maples meet the International Union for Conservation of Nature criteria for being under threat of extinction in their native habitat.
The leaves are used as a food plant for the larvae of a number of the Lepidoptera order.. In high concentrations, like the greenstriped mapleworm, can feed on the leaves so much that they cause temporary defoliation of host maple trees. Aphids are very common sap-feeders on maples. In horticultural applications a dimethoate spray will solve this. In the United States and Canada, all maple species are threatened by the Asian long-horned beetle. Infestations have resulted in the destruction of thousands of maples and other tree species in Illinois, New Jersey and New York. Maples are affected by a number of fungal diseases. Several are susceptible to Verticillium wilt caused by Verticillium species, which can cause significant local mortality. Sooty bark disease, caused by Cryptostroma species, can kill trees that are under stress due to drought. Death of maples can be caused by Phytophthora root rot and Ganoderma root decay. Maple leaves in late summer and autumn are disfigured by "tar spot" caused by Rhytisma species and mildew caused by Uncinula species, though these diseases do not have an adverse effect on th