Dinosaur+Extinction+(expert)

How did dinosaurs go extinct? Scientists have several different theories on how dinosauers went extinct.I am going to talk about three of them: **sand flies, infected vegetation,** and **meteors**.

The first one I am going to talk about is **sand flies**. Sand flies carry a disease called Lieshmaniasis (leash-ma-nigh-a-sis). It was transfered when the sand flies bit the dinosaurs. There are two types of leishmaniasis one is cutaneous lieshmaniasis. Symptoms of cutaneous lieshmaniasis are sores or ulcers on the skin. The other is called visceral lieshmaniasis. It mainly targets the internal organs. It causes the spleen to swell and sometimes bone marrow loss. The sand flies would into the dinosaurs skin with thier knife like proboscides. Then they transfer lieshmaniasis to the dinosaurs. The dinosaurs would then get sick and die. Then another dinosaur would walk by and find the dead dinosaur and eat it. The dinosaur that ate the dead one would get sick and die and the pattern would keep going. Another reason scientists believe dinosaurs went extinct is **infected vegetation**. Bugs would lay eggs on the leaves the herbivores ate and make them sick. The sickness would cause them to die. then carnivores would find the dead body and eat it. They would get sick, die and the pattern keeps going.

The last one i am going to talk about is **meteors**. Scientists think that a chain of meteors hits the earth every hundred million years. This may have happened during the time of dinosaurs and caused thier extinction. Now you know several different theories on how dinosaurs went extinct.

Biblioghraphy: Sand Fly pic: by [|**Fernanda Colla**] (© All Rights reserved) http://www.flickr.com/photos/11833528@N07/1530231385 Meteor pic: by [|**quapan**] (Creative Commons License: [|Attribution]) http://www.flickr.com/photos/9361468@N05/1357630710