Evolution Of Invasive Species

The number of wild animals on Earth has halved in the past 40 years . Creatures across the land, rivers, and the seas are destroyed as humans killed them for food in unsuitable numbers, while polluting or destroying their habitats.

The last mechanism of extinction is habitat fragmentation. This is the process by which habitat loss results in the division of large, continuous habitats into smaller, more isolated remnants. A perfect example of this is the Sumatran Rhino that was such a big population that was considered a pest until their habitat was fragmented. This decreased their population and when put in captive breeding they decreased even

The scale and pace of change is dramatic; for example, the extinction of species is occurring at around 100-fold pre-human rates4. The population sizes of vertebrate species have, on average, declined by half over the last 45 years5. More than 2.3 million km2 of primary forest has been felled since 20006. About

Many species vital to ensuring that today’s environment will thrive are becoming extinct. If a species is slowly dwindling, and in imminent danger of becoming nonexistent, this species is considered to be endangered. “One in four mammals, one in eight birds, one third of all amphibians and 70% of the world’s assessed plants on the… IUCN Red List are in jeopardy” (IUCN, 2016). According to the International Union for Conservation of Nature, or IUCN, upwards of 16,000 species are threatened with extinction, including both plants and animals (IUCN, 2016). Before becoming endangered, a species will show warning signs, either by starting to lose biological diversity or by losing the habitats for that species to flourish in, or in the worst case, both. The word endangered can sometimes be confused with threatened, extirpated, or extinct. Extirpated refers to the state of a species where its population has died out in a certain area or range, but other populations of said species still exist elsewhere (Olden, Julian D., 2008). When a species is considered threatened, or vulnerable, this refers to the state of the species being susceptible to endangerment and extinction (“Extinction crisis escalates”). So if a species is threatened, the first signs of endangerment come along, which are similar signs to that of a species in danger of becoming threatened, including lack of genetic diversity, or overhunting may be evident. (“Extinction crisis escalates”). When a species is labelled

Extinction: Most species become extinct because they can’t cope with the environmental change, and also because of introduced species that turned into competitors for

Forests have been cut, crops planted, pastures seeded, and urban areas paved. One of the most troubling consequences of human modification of ecosystems is an ongoing loss of species and therefore a loss of biodiversity around the world. The current extinctions have a human cause: habitat loss (such as clearing of tropical rainforests); the introduction of invasive species; unregulated hunting and fishing; and pollution of water, air, and

Some of the ways we have extinguished species include, climate change, air pollution causing ocean acidification, accidental imports of plants animals or fungi, fragmenting and destroying habitats, and poaching and killing animals for resources. I agree with Kolbert. We humans are making the planet difficult for other species to live in. One of the ways that we are killing species is accidental or intentional imports of plants and animals. Kolbert talked about the Pangea.

Deforestation of rainforests as such, physically kills of plant species, and these plants and the environment they form are the habitats that are vastly inhabited by all types of living matter, from elephants in the African jungles, to the beetles that live in logs. An approximation of extinct species of mammals would be about 60, since 1600. 125 species of birds have also become extinct since then. Currently, there are around 1000 to 1100 species of birds and mammals that are facing extinction, or on the brink of extinction. Including plants and invertebrates too would bring this number to 20 000. This is solely to do with the fact that Europeans use whatever land available to make way for industrial, commercial and residential use.

Some may say, were not the main reason behind most of the extinction, landslides, volcanoes, and earthquakes destroying habitats, like the dinosaurs is causing the extinctions. The Ice Age killed off the saber-toothed cats, giant ground sloths, mastodons, and mammoths. Us humans killed 322 animals to extinction in just 500 years alone, due to destroying habitats, air pollution, and

Since the beginning of life itself, some species have lived and prospered while other species have gone extinct never to be seen again by mankind. Because of this, some would claim that extinction is natural and not significantly problematic to the world that we live in. Others, however, understand that due to climate change, habitat loss, and poaching, more and more species are becoming endangered which leads to a chain reaction that can be devastating to ecosystems. Species such as the Chinook salmon, gorillas, tropical sharks, and polar bears are all directly affected by climate change, species such as northern spotted owls, Sumatran tigers, and lemurs are greatly harmed due to habitat loss, and species such as the sea turtle, Javan rhinoceros, African elephant, and the Red-Fronted Macaw are all affected by poaching driving them all closer and closer to becoming extinct.

It’s clear that a great extinction is coming from the evidence of the destruction of other species around us. The choices made by the human race have too often negatively affected the surrounding species. Tracy Wilson, the site director for HowStuffWorks.com, in an article for Animal Planet, states that

Habitat destruction, deforestation, ozone depletion, global warming, and poaching. These actions and ecological happenings are creating a world where animals are going extinct at rapid rates. Our world is on the brink of what scientists believe is the sixth mass extinction. Unlike the five previous mass extinction, the latest one killing a majority of the dinosaurs, the main causes for this current extinction are anthropogenic reasons, not natural events.

Over 98% of all organisms that have lived on Earth are now extinct. A mass extinction event occurs when a large number of species die out within a small time frame (relative to the age of Earth). Mass extinctions are intensively studied for both cause and effect, as there is usually room for debate regarding catalysts that precede the extinction and the massive influx of new biological species that follows. There have been five major mass extinctions, dubbed the “Big Five,” that have wiped out at least 50% of the species living at those times. The most well known mass extinction of the Big Five, with the decimation of every species of non-avian dinosaur, is the Cretaceous-Paleogene

Deforestation for agricultural purposes and the expansion of human habitats is happening around the world. This

The health of the earth degrades with the destructive activity of human beings. A recent study by a group of scientists looked at twenty four different services that the earth’s ecosystems provide for humans, ecosystem services, and found that fifteen of them are in need of desperate help (Gazette 31 March 2005). These services are vital to the survival of both human and nonhuman life and include filtering water and providing nutrient rich soils and ocean waters. Many of the members of these various ecosystems are also decreasing in numbers. In a British survey of bird populations found that in the 200 birds of Britain tracked there was about a 54% population decrease between the 1968-1971 tacking period and the 1988-1991 tacking period. In two other surveys of 254 native plant species from the same area there was a decrease of about 28% during the past 40 years. Humans are pushing the sixth mass extinction (Gazette March 19, 2004).