Little penguin
The little penguin is the smallest species of penguin. It grows to an average of 33 cm in height and 43 cm in length, though specific measurements vary by subspecies, it is found on the coastlines of southern Australia and New Zealand, with possible records from Chile. In Australia, they are called fairy penguins because of their small size. In New Zealand, they are more known as little blue penguins or blue penguins owing to their slate-blue plumage; the little penguin was first described by German naturalist Johann Reinhold Forster in 1781. Several subspecies are known; the holotypes of the subspecies E. m. variabilis and Eudyptula minor chathamensis are in the collection of the Museum of New Zealand Te Papa Tongarewa. The white-flippered penguin is sometimes considered a subspecies, sometimes a distinct species, sometimes a morph. Genetic analyses indicate that the Australian and Otago little penguins may constitute a distinct species. In this case the specific name minor would devolve on it, with the specific name novaehollandiae suggested for the other populations.
This interpretation suggests that E. novaehollandiae individuals arrived in New Zealand between AD 1500 and 1900 while the local E. minor population had declined, leaving a genetic opening for a new species. Mitochondrial and nuclear DNA evidence suggests the split between Eudyptula and Spheniscus occurred around 25 million years ago, with the ancestors of the white-flippered and little penguins diverging about 2.7 million years ago. Like those of all penguins, the little penguin's wings have developed into flippers used for swimming; the little penguin grows to between 30 and 33 cm tall and weighs about 1.5 kg on average. The head and upper parts are blue in colour, with slate-grey ear coverts fading to white underneath, from the chin to the belly, their flippers are blue in colour. The dark grey-black beak is 3–4 cm long, the irises pale silvery- or bluish-grey or hazel, the feet pink above with black soles and webbing. An immature individual will have lighter upperparts. Like most seabirds, they have a long lifespan.
The average for the species is 6.5 years, but flipper ringing experiments show in exceptional cases up to 25 years in captivity. The little penguin breeds along the entire coastline of New Zealand, southern Australia. Australian colonies exist in New South Wales, Tasmania, South Australia, Western Australia. Little penguins have been reported from Chile and South Africa, but it is unclear whether these birds were vagrants; as new colonies continue to be discovered, rough estimates of the world population are around 350,000-600,000 animals. Overall, little penguin populations in New Zealand have been decreasing; some colonies have gone extinct and others continue to be at risk. Some new colonies have been established in urban areas; the species is not considered endangered in New Zealand, with the exception of the white-flippered subspecies found only on Banks Peninsula and nearby Motunau Island. Since the 1960s, the mainland population has declined by 60-70%. Australian little penguin colonies exist on offshore islands, where they are protected from feral terrestrial predators and human disturbance.
Colonies are found from Port Stephens in northern New South Wales around the southern coast to Fremantle, Western Australia. An endangered population of little penguins exists in Sydney's North Harbour; the population is protected under the NSW Threatened Species Conservation Act 1995 and has been managed in accordance with a Recovery Plan since the year 2000. The population once has decreased to around 60 pairs of birds; the decline is believed to be due to loss of suitable habitat, attacks by foxes and dogs and disturbance at nesting sites. The largest colony in New South Wales is on Montague Island. Up to 8000 breeding pairs are known to nest there each year. A population of about 5,000 breeding pairs exists on Bowen Island; the colony has increased from 500 pairs in 1979 and 1500 pairs in 1985. During this time, the island was leased; the island was vacated in 1986 and is controlled by the federal government. In South Australia, many little penguin colony declines have been identified across the state.
In some cases, colonies have declined to extinction, while others have declined from thousands of animals to few. A report released in 2011 presented evidence supporting the listing of the statewide population or the more monitored sub-population from Gulf St. Vincent as Vulnerable under South Australia's National Parks & Wildlife Act 1972; as of 2014, the little penguin is not listed as a species of conservation concern, despite ongoing declines at many colonies. Tasmanian little penguin population estimates range from 110,000–190,000 breeding pairs of which less than 5% are found on mainland Tasmania. Ever-increasing human pressure is predicted to result in the extinction of colonies on mainland Tasmania; the largest colony of little penguins in Victoria is located at Phillip Island, where the nightly'parade' of penguins across Summerland Beach has been a major tourist destination, more a major conser
Binomial nomenclature
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi
Falkland Islands
The Falkland Islands is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about 300 miles east of South America's southern Patagonian coast, about 752 miles from the northern tip of the Antarctic Peninsula, at a latitude of about 52°S; the archipelago, with an area of 4,700 square miles, comprises East Falkland, West Falkland and 776 smaller islands. As a British overseas territory, the Falklands have internal self-governance, the United Kingdom takes responsibility for their defence and foreign affairs; the Falkland Islands' capital is Stanley on East Falkland. Controversy exists over the Falklands' discovery and subsequent colonisation by Europeans. At various times, the islands have had French, British and Argentine settlements. Britain reasserted its rule in 1833. In April 1982, Argentine forces temporarily occupied the islands. British administration was restored two months at the end of the Falklands War. Most Falklanders favour the archipelago remaining a UK overseas territory, but its sovereignty status is part of an ongoing dispute between Argentina and the United Kingdom.
The population consists of native-born Falkland Islanders, the majority of British descent. Other ethnicities include French and Scandinavian. Immigration from the United Kingdom, the South Atlantic island of Saint Helena, Chile has reversed a population decline; the predominant language is English. Under the British Nationality Act 1983, Falkland Islanders are British citizens; the islands lie on the boundary of the subantarctic oceanic and tundra climate zones, both major islands have mountain ranges reaching 2,300 feet. They are home to large bird populations, although many no longer breed on the main islands because of competition from introduced species. Major economic activities include fishing and sheep farming, with an emphasis on high-quality wool exports. Oil exploration, licensed by the Falkland Islands Government, remains controversial as a result of maritime disputes with Argentina; the name "Falkland Islands" comes from Falkland Sound, the strait that separates the two main islands.
The name "Falkland" was applied to the channel by John Strong, captain of an English expedition which landed on the islands in 1690. Strong named the strait in honour of Anthony Cary, 5th Viscount of Falkland, the Treasurer of the Navy who sponsored his journey; the Viscount's title originates from the town of Falkland, Scotland—the town's name comes from a Gaelic term referring to an "enclosure", but it could less plausibly be from the Anglo-Saxon term "folkland". The name "Falklands" was not applied to the islands until 1765, when British captain John Byron of the Royal Navy, claimed them for King George III as "Falkland's Islands"; the term "Falklands" is a standard abbreviation used to refer to the islands. The Spanish name for the archipelago, Islas Malvinas, derives from the French Îles Malouines—the name given to the islands by French explorer Louis-Antoine de Bougainville in 1764. Bougainville, who founded the islands' first settlement, named the area after the port of Saint-Malo; the port, located in the Brittany region of western France, was in turn named after St. Malo, the Christian evangelist who founded the city.
At the twentieth session of the United Nations General Assembly, the Fourth Committee determined that, in all languages other than Spanish, all UN documentation would designate the territory as Falkland Islands. In Spanish, the territory was designated as Islas Malvinas; the nomenclature used by the United Nations for statistical processing purposes is Falkland Islands. Although Fuegians from Patagonia may have visited the Falkland Islands in prehistoric times, the islands were uninhabited when Europeans first discovered them. Claims of discovery date back to the 16th century, but no consensus exists on whether early explorers discovered the Falklands or other islands in the South Atlantic; the first recorded landing on the islands is attributed to English captain John Strong, who, en route to Peru's and Chile's littoral in 1690, discovered the Falkland Sound and noted the islands' water and game. The Falklands remained uninhabited until the 1764 establishment of Port Louis on East Falkland by French captain Louis Antoine de Bougainville, the 1766 foundation of Port Egmont on Saunders Island by British captain John MacBride.
Whether or not the settlements were aware of each other's existence is debated by historians. In 1766, France surrendered its claim on the Falklands to Spain, which renamed the French colony Puerto Soledad the following year. Problems began when Spain discovered and captured Port Egmont in 1770. War was narrowly avoided by its restitution to Britain in 1771. Both the British and Spanish settlements coexisted in the archipelago until 1774, when Britain's new economic and strategic considerations led it to voluntarily withdraw from the islands, leaving a plaque claiming the Falklands for King George III. Spain's Viceroyalty of the Río de la Plata became the only governmental presence in the territory. West Falkland was left abandoned, Puerto Soledad became a prison camp. Amid the British invasions of the Río de la Plata during the Napoleonic Wars in Europe, the islands' governor evacuated the archipelago in 1806. Thereafter, the archipelago was visited only
Punta Tombo
Punta Tombo is a peninsula into the Atlantic Ocean 110 km south of Trelew in Chubut Province, where there is a large colony of Magellanic penguins - the largest such colony in South America. It is a short distance north of Camarones; the 2.1 km2 Punta Tombo Provincial Reserve has been protected since 1979, according to a provincial decree, it is one of the main tourist attractions in Chubut. Punta Tombo is part of the new marine national park at Golfo San Jorge; the 3 km long, 600 m wide peninsula is covered with sand and gravel. In late September, with the arrival of spring, thousands of Magellanic penguins migrate to Punta Tombo from southern Brazil to nest, they stay at the site until April, incubating their eggs, raising their chicks, preparing for migration. Couples stand in front of their nests, protecting the eggs from birds and other predators, one adult goes to the sea for food. Other important nearby colonies are Cabo Dos Bahías. A variety of other wildlife can be encountered in the area, including seabirds and guanacos.
In the 19th Century, British mariners knew Punta Tombo as "Tombas". Punta Ninfas Península Valdés Citations ReferencesClayton, Jane M. Ships employed in the South Sea Whale Fishery from Britain: 1775-1815: An alphabetical list of ships.. ISBN 978-1908616524 Puntatombo.com Destinations Patagonia.com.ar Punta Tombo, images
Chile
Chile the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, the Drake Passage in the far south. Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez and Easter Island in Oceania. Chile claims about 1,250,000 square kilometres of Antarctica, although all claims are suspended under the Antarctic Treaty; the arid Atacama Desert in northern Chile contains great mineral wealth, principally copper. The small central area dominates in terms of population and agricultural resources, is the cultural and political center from which Chile expanded in the late 19th century when it incorporated its northern and southern regions. Southern Chile is rich in forests and grazing lands, features a string of volcanoes and lakes; the southern coast is a labyrinth of fjords, canals, twisting peninsulas, islands.
Spain conquered and colonized the region in the mid-16th century, replacing Inca rule in the north and centre, but failing to conquer the independent Mapuche who inhabited what is now south-central Chile. After declaring its independence from Spain in 1818, Chile emerged in the 1830s as a stable authoritarian republic. In the 19th century, Chile saw significant economic and territorial growth, ending Mapuche resistance in the 1880s and gaining its current northern territory in the War of the Pacific after defeating Peru and Bolivia. In the 1960s and 1970s, the country experienced severe left-right political polarization and turmoil; this development culminated with the 1973 Chilean coup d'état that overthrew Salvador Allende's democratically elected left-wing government and instituted a 16-year-long right-wing military dictatorship that left more than 3,000 people dead or missing. The regime, headed by Augusto Pinochet, ended in 1990 after it lost a referendum in 1988 and was succeeded by a center-left coalition which ruled through four presidencies until 2010.
The modern sovereign state of Chile is among South America's most economically and stable and prosperous nations, with a high-income economy and high living standards. It leads Latin American nations in rankings of human development, income per capita, state of peace, economic freedom, low perception of corruption, it ranks high regionally in sustainability of the state, democratic development. Chile is a member of the Organisation for Economic Co-operation and Development, joining in 2010, it has the lowest homicide rate in the Americas after Canada. Chile is a founding member of the United Nations, the Union of South American Nations and the Community of Latin American and Caribbean States. There are various theories about the origin of the word Chile. According to 17th-century Spanish chronicler Diego de Rosales, the Incas called the valley of the Aconcagua "Chili" by corruption of the name of a Picunche tribal chief called Tili, who ruled the area at the time of the Incan conquest in the 15th century.
Another theory points to the similarity of the valley of the Aconcagua with that of the Casma Valley in Peru, where there was a town and valley named Chili. Other theories say Chile may derive its name from a Native American word meaning either "ends of the earth" or "sea gulls". Another origin attributed to chilli is the onomatopoeic cheele-cheele—the Mapuche imitation of the warble of a bird locally known as trile; the Spanish conquistadors heard about this name from the Incas, the few survivors of Diego de Almagro's first Spanish expedition south from Peru in 1535–36 called themselves the "men of Chilli". Almagro is credited with the universalization of the name Chile, after naming the Mapocho valley as such; the older spelling "Chili" was in use in English until at least 1900 before switching to "Chile". Stone tool evidence indicates humans sporadically frequented the Monte Verde valley area as long as 18,500 years ago. About 10,000 years ago, migrating indigenous Peoples settled in fertile valleys and coastal areas of what is present-day Chile.
Settlement sites from early human habitation include Monte Verde, Cueva del Milodón and the Pali-Aike Crater's lava tube. The Incas extended their empire into what is now northern Chile, but the Mapuche resisted many attempts by the Inca Empire to subjugate them, despite their lack of state organization, they fought against his army. The result of the bloody three-day confrontation known as the Battle of the Maule was that the Inca conquest of the territories of Chile ended at the Maule river. In 1520, while attempting to circumnavigate the globe, Ferdinand Magellan discovered the southern passage now named after him thus becoming the first European to set foot on what is now Chile; the next Europeans to reach Chile were Diego de Almagro and his band of Spanish conquistadors, who came from Peru in 1535 seeking gold. The Spanish encountered various cultures that supported themselves principally through slash-and-burn agriculture and hunting; the conquest of Chile began in earnest in 1540 and was carried out by Pedro de Valdivia, one of Francisco Pizarro's lieutenants, who founded the city of Santiago on 12 February 1541.
Although the Spanish did not find the extensive gold and silver they sought, they recognize
Yellow-eyed penguin
The yellow-eyed penguin or hoiho is a penguin native to New Zealand. Thought related to the little penguin, molecular research has shown it more related to penguins of the genus Eudyptes. Like most other penguins, it is piscivorous; the species breeds along the eastern and south-eastern coastlines of the South Island of New Zealand, as well as Stewart Island, Auckland Islands, Campbell Islands. Colonies on the Otago Peninsula are a popular tourist venue, where visitors may observe penguins from hides, trenches, or tunnels. On the New Zealand mainland, the species has experienced a significant decline over the past 20 years. On the Otago Peninsula, numbers have dropped by 75% since the mid-1990s and population trends indicate the possibility of local extinction in the next 20 to 40 years. While the effect of rising ocean temperatures is still being studied, an infectious outbreak in the mid 2000s played a large role in the drop. Human activities at sea may have an equal if not greater influence on the species' downward trend.
The yellow-eyed penguin is the sole extant species in the genus Megadyptes. Thought related to the little penguin, new molecular research has shown it more related to penguins of the genus Eudyptes. Mitochondrial and nuclear DNA evidence suggests it split from the ancestors of Eudyptes around 15 million years ago; the yellow-eyed penguin was described by Jacques Bernard Hombron and Honoré Jacquinot in 1841. The Māori name is hoiho; this is a mid-sized penguin. Weights vary through the year being greatest, 5.5 to 8 kg, just before moulting and least, 3 to 6 kg, after moulting. The males are larger than the females, it paler yellow iris with black feather shafts. The chin and throat are brownish-black. There is a band of bright yellow running from its eyes around the back of the head; the juvenile has a greyer head with no band and their eyes have a grey iris. The yellow-eyed penguin may be long lived, with some individuals reaching 20 years of age. Males are longer lived than females, leading to a sex ratio of 2:1 around the age of 10–12 years.
This penguin nests in forest or scrub, among native flax and lupin, on slopes or gullies, or the shore itself, facing the sea. These areas are sited in small bays or on headland areas of larger bays, it is found in New Zealand, on the south-east coast of the South Island most notably on Otago Peninsula, Foveaux Strait, Stewart Island, sub-Antarctic islands of Auckland and Campbell Islands. It expanded its range from the sub-Antarctic islands to the main islands of New Zealand after the extinction of the Waitaha penguin several hundred years ago. In spring 2004, a undescribed disease killed off 60% of yellow-eyed penguin chicks on the Otago peninsula and in North Otago; the disease has been linked to an infection of Corynebacterium, a genus of bacteria that causes diphtheria in humans. It has been described as diphtheritic stomatitis. However, it seems; the primary pathogen remains unknown. A similar problem has affected the Stewart Island population; the yellow-eyed penguin forages predominantly over the continental shelf between 2 km and 25 km offshore, diving to depths of 40 m to 120 m Breeding penguins undertake two kinds of foraging trips: day trips where the birds leave at dawn and return in the evening ranging up to 25 km from their colonies, shorter evening trips during which the birds are away from their nest longer than four hours or range farther than 7 km.
Yellow-eyed penguins are known to be an exclusive benthic forager that searches for prey along the seafloor. Accordingly, up to 90% of their dives are benthic dives; this means that their average dive depths are determined by the water depths within their home ranges. Around 90% of the yellow-eyed penguin's diet is made up of fish, chiefly demersal species that live near the seafloor. Other species taken are cephalopods such as arrow squid. Jellyfish including species in the genera Chrysaora and Cyanea were found to be sought-out food items, while they had been thought to be only accidentally ingested. Similar preferences were found in little penguin and Magellanic penguin. Whether yellow-eyed penguins are colonial nesters has been an ongoing issue with zoologists in New Zealand. Most Antarctic penguin species nest in large high density aggregations of birds. For an example see the photo of nesting emperor penguin. In contrast yellow-eyed penguins do not nest within visual sight of each other. While they can be seen coming ashore in groups of four to six or more individuals disperse along track to individual nests sites out of sight of each other.
The consensus view of New Zealand penguin workers is that it is preferable to use habitat rather than colony to refer to areas where yellow-eyed penguins nest. Nest sites are selected in August and two eggs are laid in September; the incubation duties are shared by both parents. For the first six weeks after hatching, the chicks are guarded during the day by one parent while the other is at sea feeding; the foraging adult returns at least daily to feed the chicks and relieve the partner
Animal
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
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