Ch. 6 Lesson 3How do changes
cause more changes?
pesticide•poison that kills insects
Mosquitoes spread diseases- Mosquitoes spread diseases- malaria & West Nile virusmalaria & West Nile virus
Some mosquitoes develop adaptations to survive pesticides.
They inherited genes that allow them to survive around the
pesticide.
antibiotics• medicines used to kill disease-causing bacteria
Some bacteria develop adaptations to survive antibiotics-
makes diseases harder to treat.
extinct• species where no members
of its kind are alive
dodo bird
fossils• sources of evidence of past
extinctions of plants & animals
bald eagle1. pesticides (DDT)
washed into rivers & streams
2. fish - DDT 3. eagle ate fish 4. caused birds to lay thin
shelled eggs5. 1972-DDT banned6. population began to
recover
DDTDDTdichlorodiphenyltrichloroethane
DDT makes birds’ shells thin
Bald eagles could not adapt to
pesticide.Bald Eagle Web Cam