Am nevoie de un referat cu 3 specii pe cale de disparitie.
Referatul trebuie sa fie in limba engleza si sa fie de o pagina
!!!!!!! Dau coroana.!!!!!!!!
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Elephants. Tigers. Gorillas. Panda. Blue whales. What do these amazing creatures have in common? They are some of the largest, strongest and most beloved animals on the planet. All these are also endangered species.
An animal or plant is on the verge of extinction when there are so few living specimens on the planet that the entire species is in danger of disappearing forever. When none of a species survives anywhere on Earth, it is considered extinct. Unfortunately, one of eight species of birds, one of four mammals, one of three amphibians and one of five plants are endangered.
Scientists estimate that there are between 7 and 10 million species on Earth. The total sum of all these species is called Earth's biodiversity. Biodiversity includes an incredible range of living organisms, from centipedes to dolphins, to snake bells.
How did so many species arrive? It didn't happen overnight.
The earth is old and wonderful - about 4.5 billion years old. And life on Earth has lasted over 2 billion years. From the oldest single-celled creatures, species have evolved in amazing ways. Think a little at your feet. There are creatures with four legs (lions, dogs, elephants), eight legs (spiders), two legs (pigeons, humans) and no legs (snakes, worms, whales). The famous biologist, Charles Darwin, once called the variety of life on Earth "the most endless forms." The species of the world have evolved and adapted to survive in all types of environments and ecosystems. They live in oceans and deserts, in pastures and caves, almost anywhere on Earth.
Polar bears
The polar bears in the picture use summer ice in the Arctic Sea as a platform for seal hunting. But due to global warming, this specialized habitat is shrinking.
Of course, there have been many changes in world biodiversity over time. Part of the evolution process means that some species will disappear, and new ones will evolve to fit in changing environments. But this process usually happens over very long periods of time. Typically, only a few species disappear within 100 or even 1000 years.
However, during Earth's history there were some extreme events that killed a large number of species. These events are called mass extinctions. A mass extinction that you probably know is the disappearance of dinosaurs. A catastrophic event - most likely a large asteroid that hit Earth 65 million years ago - created such a disaster that 75% of the world's species have disappeared. There have been five mass extinctions in the history of our planet.
Unfortunately, if you look at the rate at which animals have disappeared in the last 500 years and the increasing number of species that have disappeared or are in danger of extinction, it seems that we are at the beginning of another mass extinction. In fact, some scientists already call it the sixth extinction. What is the extreme event that causes the sixth disappearance? The answer is: human beings.
Most people love animals, but many things we do as humans are not good for other species.