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