Factors that classified species endangeredby Alesandra Ibobo | 19-05-2018 22:05 |
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1.jpg) 8.jpg) 2.jpg) An endangered specie is a type of organism that is threatened by extinction. Species become endangered for two main reasons: loss of habitat and loss of genetic variation. A loss of habitat can happen naturally. Dinosaurs for instance lost their habitat 65 million years ago. The hot dry climate of cretaceous period change very quickly most likely because of an asteroid striking the earth. The impact of asteroid force debris into atmosphere reducing the amount of heat and light that reach the earth surface. The dinosaurs were unable to adopt the new cooler habitat, Dinosaurs became endangered. Human activities can also contribute to loss of habitat, such as development, housing industry and agriculture. Development eliminates habitat and nature species. In the Amazon rainforest developers have clear thousands of acres of land, remove trees and vegetation. Rainforest provide habitat for other species, tree crown provide habitat in the top layer of a rainforest, insect, butterflies and monkeys. If the trees are cut down, in this course habitat loss many animals have a range of hunches of square kilometres. The mountain lion of North America for instance has a range of 1000 square kilometers to successfully live and reproduce a single mountain lion patrols this much territory area such as Los Angeles, California and Vancouver as these area expand into wilderness. The mountain lion habitat became smaller that means it will support fewer mountain lion. Loss of genetic variation Genetic variation is the diversity found within species. Its why human beings may have blond, red, brown, black hair. Genetic variation allows species to adopt to change in environment, the greater species, the greater the population of the species, the greater its variation in breeding is the reproduction with close family members. Disease is much more common and deadly among in breed group because no new information is introduced to the group so they don't have resistance to disease. Cheetah are endangered species nature to Africa / Asia. These big cats have very genetic variation. Biologist say that during the last ice age cheetah went through a long period of inbreeding as a result, there are very few genetic differences between cheetah. They cannot adapt to new environment so their fewer survival to maturity. Human activity Over hunting and overfishing have reduce the population of many animals. Two different species of animals cannot make healthy offspring with that genetic variation shrink. Factor that classified species as endangered Population reduction rate Geographic range Population size Population restrictions Probability of extinction Population reduction rate: A specie is classified as endangered when its population has declined between 50 to 70 percent. It is measured over 10years of three generation of the species. It is also declared when the cause of its decline is not known or it is also known. Geographic range: An endangered species' extent of occurrence is less than 5000 square kilometers (1,930 square miles). An endangered species area of occupancy is less than 500 square kilometers (193 square miles). Population size: A species is classified as endangered when there are fewer than 2,500 mature individuals, when a species population declines by at least 20 percent within 5 years or 2 generation. Population restriction: when it population is restricted to less than 250 mature individual when a species population is low, it area of occupancy is not considered than it is classified as endangered. Probability of extinction: In the wild is at least 20 percent within 20 years or 5 generation is which ever is longer
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