Lecture 10 Slides

Lecture 10 Slides - Lecture 10 Pesticides and herbicides as...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 10 Lecture 10 Pesticides and herbicides as disruptors of endocrine function Bioloical basis of sexual differentiation and sexual preference
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Atrazine controversy (see related link) Objections raised to Hayes’ studies: Viruses can account for declines in amphibian populations Multiple deformities lumped together- hermaphroditism and pigmentation of gonads Site selection for field studies inappropriate Other studies find a higher threshold for atrazine effects Atrazine’s effects on amphibians may be to increase susceptability to parasites and depend upon crowding Hayes’ response: Syngenta bought favorable research from consultants Atrazine effects shown in lab studies where viruses not a factor Controls were crowded, underfed to raise baseline levels of abnormality Results have been replicated in other labs (Atrazine banned in Europe on the basis of this work).
Background image of page 2
Field studies at 8 U.S. localities done to correlate levels of atrazine and its derivatives with gonadal malformations in Leopard frogs ( Rana pipiens ) Gonadal abnormalities are not correlated with hghest levels of atrazine - but Atrazine derivatives may Contribute to the effect
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Are sperm counts declining in Human populations? Travison et al. 95% CI
Background image of page 4
Atrazine was re-licensed by EPA, with warning label modified after resistance by Syngenta
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
A New Theory To Explain The Frog Decline? Dennis Avery and Alex Avery Scientists around the world are worried about frogs. Many frog populations are in decline, and we don't know why. We've found some small clues: something called the ranovirus is hampering efforts to restore leopard frog populations in Alberta, Canada, where they were once abundant. The chytrid fungus, which has caused frog die-offs in Australia, Africa, and Central America, has also been found in the United States. Some false leads have also been run down. When Minnesota school kids found deformed frogs in some local ponds, the finger of accusation was pointed at pesticides. Now, the deformities have been traced to a natural parasite, the trematode, which burrows into the just-forming leg joints of tadpoles. The absence of yellow-legged frogs in some California mountain lakes had been blamed on pesticide-laden dust rising from the intensively farmed San Joaquin Valley. However, when the fish management teams stopped stocking the mountain lakes with hungry trout, the frogs returned in large numbers. Pesticides are still a favorite bogyman of concerned frog lovers on Internet blogs, however, and
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/18/2008 for the course BIO 105 taught by Professor Adler,irschick,podos during the Fall '08 term at UMass (Amherst).

Page1 / 25

Lecture 10 Slides - Lecture 10 Pesticides and herbicides as...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online