Cretaceous extinction also known as Paleogene extinction was a period of time when suddenly around three quarter of the animal and plant species began to get extinct from the land. The event happened around 66 million years ago and is considered as the end of cretaceous era that lead to the beginning of Mesozoic era.
Reasons for the mass extinction:
- Scientists think that a major asteroid or comet hit the surface of earth which deteriorated the earth’s environment, especially by making it difficult for plants to perform the process of photosysnthesis. This is called as Impact hypothesis and scientists think that it was the reason of extinction of so many species because they found debris of asteroid in the land.
- There could also be some other reasons like climate changes,volcanic eruptions and changes in the sea level which made the environment unfavorable for the survival of living organisms.
- One of the best known organism that is thought to extinct in cretaceous period was dinosaur.
Extinction of Dinosaurs:
As stated above the exact cause of dinosaur extinction can not be stated with confidence. This is because cretaceous period was the time when so many unfavorable circumstances took place like diseases, geologic events ,climate change etc.
However, the most believed theory is that some Asteroid hit the surface of earth and turned the climate very very old. Therefore, those amazing creatures were not able to survive that climate.
Hope it help!
An example of a haploid cell is the sperm cell. A haploid cell has a complete set of chromosomes. Through meiosis, a haploid cell called the gametes is produced. Haploid cells could also refer to the number of chromosomes in an egg or a sperm cell.
The correct answer is fixed migration pattern.
Extinction means termination of last member of a particular species. This can be due to various factors. The reason could be natural or human interventions. The best characteristics of an organism to be less likely to face extinction are the fixed migration pattern. Migration of that particular species in a fixed pattern will make them adapt different environment. This saves the species from natural extinction. Even if the species of a particular geographical area dies the migrated species will be alive to breed and save the species from extinction.
