{"id":9567,"date":"2026-06-01T21:33:48","date_gmt":"2026-06-01T21:33:48","guid":{"rendered":"https:\/\/kapdec.com\/help\/?p=9567"},"modified":"2026-06-01T21:33:48","modified_gmt":"2026-06-01T21:33:48","slug":"extinction","status":"publish","type":"post","link":"https:\/\/kapdec.com\/help\/extinction\/","title":{"rendered":"Extinction"},"content":{"rendered":"

Unit : Natural selection<\/strong><\/h2>\n

Chapter: Extinction<\/strong><\/h3>\n

Reference:<\/em><\/strong> Extinction, Effect of extinction, Causes of Extinction, Asteroid Strikes, Climate Change, Disease, Loss of habitat, Lack of Genetic Diversity, Better Adapted Competition, Pollution, Relation between speciation and extinction, Relation between extinction and adaptive radiation<\/em><\/p>\n

Learning objectives<\/strong><\/p>\n

    \n
  • To understand the cause and effect of extinction<\/li>\n<\/ul>\n

    Extinction<\/strong><\/p>\n

    When a species becomes extinct, all its genetic heritage is lost. The species evolve into new species in order to adapt to the environmental changes or changes in the genetic heritage. Over 99% of all the species that once lived on the Earth, amounting to over five billion species, are estimated to be extinct. As per the estimations on the number of current species, a range from 10 -14 million, of which more than 1.2 million have been studied and more than 86% have not yet been discovered. This could happen naturally due to a change in the climate or because of human activities like overhunting or the destruction of habitat.<\/p>\n

    Effect of extinction<\/strong><\/p>\n

    As species go extinct, they are taken out of the food chain. Animals that ate the newly-extinct species must find new food sources or starve. This can damage the populations of other plants or animals. Furthermore, if a predator goes extinct, its prey's population can proliferate, unbalancing local ecosystems.<\/p>\n

    Causes of Extinction<\/strong><\/p>\n

    The important causes of extinction include:<\/p>\n

    Asteroid Strikes<\/strong><\/p>\n

    A meteor strike on the Yucatan peninsula in Mexico led to the disappearance of dinosaurs millions of years ago. Most of the mass extinctions, such as KT extinction or Permian-Triassic extinction, were caused due to such events. Astronomers constantly keep an eye on comets or meteors that could lead to the end of human civilization.<\/p>\n

    Climate Change<\/strong><\/p>\n

    Climate change is yet another factor that could destroy terrestrial organisms. During the end of the last ice age, most of the megafauna were unable to adapt to the changing warm temperatures. They died due to a lack of food and hunting by early humans. Even modern civilization is stepping towards the threat of extinction due to global warming.<\/p>\n

    Disease<\/strong><\/p>\n

    Various epidemics had been the cause of the epidemic of a large population of humans and animals on earth. The Black Death wiped out one-third of the European population in the Middle Ages.<\/p>\n

    Loss of habitat<\/strong><\/p>\n

    Every animal has its own comfort zone where it can breed and raise its young ones. For e.g., a bird is comfortable only on the branch of a tree. Due to the expansion of human civilization and industrialization, the forests have been destroyed, which are an abode to most animals. Due to lack of space and eventually food, the populations of many organisms have been minimised.<\/p>\n

    Lack of Genetic Diversity<\/strong><\/p>\n

    Once the number of species starts decreasing, the gene pool of that species grows smaller. Eventually, there is a lack of genetic diversity. For e.g., due to habitat loss, the African cheetahs have a considerably low genetic diversity.<\/p>\n

     <\/p>\n

    Better Adapted Competition<\/strong><\/p>\n

    The better-adapted populations win over the ones that lag. For e.g., the pre-historic mammals were better adapted than the dinosaurs. The ones which are well-adapted survive, while the others become extinct.<\/p>\n

    Pollution<\/strong><\/p>\n

    The pollution from industries and vehicles has led to a drastic change in the oxygen levels in the atmosphere as well as water. This has led to the extinction of most of the aquatic as well as terrestrial species.<\/p>\n

    Relation between speciation and extinction<\/strong><\/p>\n

    Species with smaller geographical ranges are more vulnerable to extinction. Species with narrow habitat breadths are more vulnerable to extinction. Body size is an important predictor of extinction risk, but depends on the threat. The relationship between most traits and extinction remains elusive.<\/p>\n

    Relation between extinction and adaptive radiation:<\/strong><\/p>\n

    Many ecosystems are no longer occupied by species after a mass extinction because they have gone extinct. Some species will adapt to their new habitats when new habitats become available. During these periods, evolutionary processes move quickly. To fill those accessible habitats, many new species evolve.<\/p>\n

     Summary <\/strong><\/p>\n

      \n
    • The genetic diversity is lost completely when a species become extinct<\/li>\n
    • Due to extinction, the balance of ecosystem is lost and in turn it affects all the members of the food chain<\/li>\n
    • The cause of extinction is habitat loss, climate change, asteroid strikes, pollution, better adapted conditions.<\/li>\n
    • Species with smaller geographical ranges are more vulnerable to extinction.<\/li>\n
    • Many ecosystems are no longer occupied by species after a mass extinction because they have gone extinct.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

      Unit : Natural selection Chapter: Extinction Reference: Extinction, Effect of extinction, Causes of Extinction, Asteroid Strikes, Climate Change, Disease, Loss of habitat, Lack of Genetic Diversity, Better Adapted Competition, Pollution, Relation between speciation and extinction, Relation between extinction and adaptive radiation Learning objectives To understand the cause and effect of extinction Extinction When a species […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[629],"tags":[],"class_list":["post-9567","post","type-post","status-publish","format-standard","hentry","category-ap-biology"],"_links":{"self":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9567","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/comments?post=9567"}],"version-history":[{"count":0,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9567\/revisions"}],"wp:attachment":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/media?parent=9567"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/categories?post=9567"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/tags?post=9567"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}