Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
Evolution of elephants essays
Effects of species extinction
Don’t take our word for it - see why 10 million students trust us with their essay needs.
Recommended: Evolution of elephants essays
The rapid evolution of the family Elephantidae throughout time has been extensively researched in the past decades and has resulted in many new discoveries and lineages between the genuses of Elephantidae. Throughout evolution, a majority of the species of Elephantidae have become extinct, leaving only Loxodonta africana, Loxodonta cyclotis, and Elephas maximus. The number of these species, however, has dwindled significantly in the past years due to the high number of deaths of elephants due to poaching. The continuation of poaching has a possibility of a new evolutionary event within the elephants, elephants without tusks.
Ancestors of the extant Loxodonta africana and Elephas maximus
The family of Elephantidae shows a high rate of evolution, early stages of which were confined to Africa, while later stages occurred in Eurasia (Kalmykov & Mashchenko, 2006). Numerous studies have been conducted to understand the phylogeny of Elephantidae, and many of the researches have concluded different answers. Maglio, Beden, and Todd each concluded their research with phylogenetic trees that contrasted with each other.
According to Maglio (1972), the lineages of Loxodonta, Elephas, and Mammuthus all evolved from the ancestor Primelephas gomphotheroides. Loxodonta first evolved from the Primelephas in the Pliocene time period, leaving an Elephas-Mammuthus lineage. Soon after the separation of the Elephas lineage and Mammuthus lineage took place during the Pliocene time period. Very little evolution has occurred within the Loxodonta genus in the past two and a half million years, since the only ancestor of the living Loxodonta africana is Loxodonta adaurora. The Elephas lineage however has numerous events of evolution within the genus. Ac...
... middle of paper ...
...ith elephants. If poaching continues to increase as it has in the past, the elephants may not only lose their tusks, but they may also become extremely endangered or extinct.
Works Cited
Cressey, D. 2013. Tusk tracking will tackle illegal trade. Nature 494:411-412.
Kalmykov, N.P. and E.N. Mashchenko. 2006. New data on the migration of the family Elephantidae (mammalia, proboscidea) in Eurasia. Doklady Biological Sciences 406:103-105.
Kioko, J., E. Zink, M. Sawdy, and C. Kiffner. 2013. Elephant (Loxodonta africana) demography and behavior in the Tarangire-Manyara ecosystem, Tanzania. South African Journal of Wildlife Research 43:44-51.
Maglio, V.J. 1972. Evolution of Mastication in the Elephantidae. Evolution 26:638-658
Todd, N. E. 2010. New phylogenetic analysis of the family Elephantidae based on cranial- dentalmorphology. The Anatomical Record 293:74-90.
Ceratopsians and Pachycephalosaurs Around 144 million years ago, began the emergence of the Ornithischian dinosaurs during the Cretaceous period and diversified into North America and Asia. Ornithischians were classified as having a hip structure similar to that of birds, although they are not the descendants of birds. Marginocephalians, meaning "fringed heads" are a group of Ornithischians that have a distinctive skull structure, consisting of a slight shelf or bony frill on the back of the skull, a unique palate, and a short hip structure. These herbivores include two major groups: the Ceratopsians and the Pachcephalosaurians. These plant-eaters include the Ceratopsians, horned dinosaurs such as the Triceratops, Styrachosaurus, Pentaceratops, and the Protoceratops.
Not only are giraffes the tallest animals in the world, they are also one of the most recognizable. Their characteristic long necks quickly captivate any audience. That being said, it is not commonly known that there are thought to be nine subspecies of Giraffa camelopardalis. In fact, there is increasing evidence that these could potentially be separate species in their own right. This paper will discuss where giraffes fit in the Tree of Life and identify the giraffe’s closest relatives, differentiate and analyze the similarities and differences between the nine subspecies, and, finally, explore any debate revolving around the phylogeny of the subspecies.
The name ‘Liopleurodon’ is derived from Greek. It means “smooth-sided teeth”. The name was given by Henri Emile Sauvage. Sauvage gave this name because in 1873, he found the fossils of three teeth which were just 7 centimeter in length. The two species of Liopleurodon are L. ferox and L. pachydeirus Out of the two species, L. forex is quite known and famous. The fossils of both the species are found in the countries of England and France. L. pachydeirus is a very rare species as its fossils are not discovered in very good numbers. On the other hand, the fossils of L. ferox species are found in comparatively good number. The scientists have more knowledge about L. ferox because of the availability of the skeletons; some of which are more complete or less.
Besides humans, who occupy each continent, majority primates live in tropical regions of the Africa ,Asia and also America(Anon ,1911). They are very different in size from Madame Berthe's mouse lemur, which is only 30 g (1 oz.), whereas the eastern lowland gorilla, is over 200 kg (440 lb.). According to fossil evidence, the early predecessor of primates might have been existed in the late Cretaceous period which was between 145.5 and 65.5 million years ago; an early close primate relative known from ample that still remains is the Late Paleocene Plesiadapis, circa 55–58 million years ago (Chatterjee, Ho, Barnes and Groves ,2009). The primate branch might be even older than first thought, emerging in mid-Cretaceous era which was around 85 million years ago as being suggested by the molecular clock study (Chatterjee et al. 2009).
Poaching threatens the dying out of endangered species. Lions have virtually disappeared in Africa causing animal activists to protest for stricter rules on hunting big game. Damian Aspinall, director of the Aspinall Foundation, said,
First, poaching is a huge game being played. It hurts the animals or species that are being targeted, which causes them to increase their chances of extinction. Orietta C. Estrada, an animal and environmental writer, explains that poaching "is a crime fueled by a lucrative black market trade of animal parts"(onegreenplanet). To these people, it is all about the money. They do not bother to think about how much pain this creature may feel. The only thing they desire to obtain is the big dollars. The animals that are affected by this monstrous act are elephants, tigers, rhinoceros, Tibetan antelopes, gorillas, and great apes(animalpoachers.weebly). The most they have done with dealing with the poachers is give them a cruel punishment for being caught. It does not work because it still happens today and the animals are still dying and becoming
Cohn, Jeffrey P. "Do Elephants Belong In Zoos?" Bioscience 56.9 (2006): 714-717. Academic Search Premier. Web. 24 Mar. 2014.
The common name is the African Elephant, the scientific name is Loxodonta Africana, the phylum is Vertebrata, the class is Mammalia, the order is Proboscidea, and the family is Elephantidae. The Closest Relatives to the African Elephant are: the Asian Elephant, mammoths, primitive proboscidean (mastodons), sea cows, and hyraxes. Scientists believe that the African Elephant evolved from one of its closest relatives, the Sea Cow. The geographical location and range of the African elephant covers all of central and southern Africa. In Ethiopia there are isolated populations that exist around Lake Chad in Mali and Mauritania. Also in Kenya, Rhodesia, Tanzania, Zambia, Uganda, Zaire, and in National parks located in South Africa, as well as several other countries. African Elephants, originally, were found in all of the Sub-Saharan African habitats except desert steppes. Elephants still occupy diverse habitats such as: temperate grassland, tropical savanna and grass lands, temperate forest and rainforest, tropical rainforest, tropical scrub forest, and tropical deciduous forest despite their drastic decline in numbers. However, their migratory patterns and habitat use have changed, due to the fact that they are restricted to protected areas. The elephant can exist in many types of environments but it prefers places that have many trees and bushes, which the elephant needs both for food and shade. They also like warm areas that have plenty of rainfall.
The fossil record of horses extends back to an odd-toed ungulate mammal belonging to the taxonomic family Equidae, a dog-like ancestor 55 to 42 million years ago in the genus Hyracotherium in North America. Hyracotherium had a primitively little face , four-toed forefeet, three-toed hind feet, an arched back, small brain, and higher hindquarters than forehand. Later genus has increased in body size, brain complexity, the size of cheek teeth, lengthening of the face, and reduction of toe number. However, even though horses got larger over time but these trends are not seen in all of the horse lines. Genus such as Hipparion existed from 23 to 2 million years ago, showed gains in size, But some later genus such as Archeohippus, and Calippus got smaller again (Boundless, 2016),(Encyclopedia of Life,2015), (equineworld.co.uk, 2014), (Molen, M.
The times did a first of its kind analysis of 390 elephant fatalities at accredited U.S. zoos for the past 50 years (Berens 3). It found that most of the elephants died from injury or disease linked to conditions of their captivity from chronic foot problems caused by standing on hard surfaces to musculoskeletal disorders from inactivity caused by being penned or chained for days and weeks at a time. Of the 321 elephant deaths for which The Times had complete records, half were by age 23, more than a quarter before their expected life spans of 50 to 60 years. For every elephant born in a zoo, on average another two die. At that rate, the 288 elephants inside the 78 U.S. zoos could be “demographically extinct” within the next 50 years because there’ll be too few fertile females left to breed, according to zoo industry research (Berens 4).
A new disease has recently been discovered that is now hindering elephants’ ability to survive even further. This is a major problem because according to Science Magazine, as of 1997, there are only an estimated 291 Asian elephants and 193 African elephants left in North American zoos. Since this survey was conducted, this number has declined significantly. It is now estimated that for every elephant that is born in a zoo, another three die. In the wild, female elephants are constantly pregnant or nursing.
An estimated number of 500,000 4 rhinos were roaming across Africa and Asia at the beginning of the 20th century, however this number declined to 70,000 4 by 1970 and down to 29,000 4 rhinos in the wild r...
...lled by poachers. Even the White Rhino population was hit hard because of poachers seeking their priceless horns. The Los Angeles Times reported that,” The world’s largest surviving population of white rhinos suffered its heaviest toll on record last year when poachers killed more than one- thousand of the threatened animals to feed an international market for trinkets and potions made from their horns” (Williams 1). According to the WWF, The population of the White Rhino has diminished to a mere twenty- thousand. The worst part is the rare tusks are being used for the most unbelievably useless products. The number of White Rhinos are so scarce that even the killing of one- thousand is a huge blow to the delicate and slowly increasing population. It is truly disappointing that such a majestic species is being sacrificed due to the high demand of their rare tusks.
Grubb, P. 2005, "Giraffe camelopardalis", In Wilson, D. E.; Reeder, D. M. Mammal Species of the World, Johns Hopkins University Press.
Due to lack of the lack of management and resources in the conservation programs has led to a further increase in poaching which has triggered to drastic decline in elephant populations. According to the Huffington post, a reputable news source, it reports, “an estimated 22,000 elephants were illegally killed across Africa in 2012”. In February alone there were as many as “650 elephants killed in a matter of days” If the elephant death continues at such a rapid rate it could lead to their demise. “Elephant poaching could wipe out 20 percent of African population in [the] next decade” (Huffington Post). An extinction in elephants would mean the possibly of many other species becoming endangered of going extinct as well.