topic 2 unit 3 Flashcards
how do chemicals enter the environment?
from a natural process like photosynthesis, cellular respiration, and natural cycles
What is another way that chemicals enter teh environment
human activity such as pesticides and fertilizers, garbage, sewage, electricity, and natural gas
what are pesticides
are poisons that are designed to kill and undesirable tests that can damage crops and cause human diseases
what are the three types of pesticides called
herbicides which kill weeds
insecticides kill insects
fungicides which kill fungi
what was DDT good at?
was so successful in killing agricultural insect pests as well as insects that cause human disease.
who invented DDT?
Paul muller
why was DDT so important in WWII?
it completely removed the typhus threat to armies.
and it wiped out fleas, malaria, bubonic plaque and yellow fever
what is typhus?
a disease carried by Lice
why was DDT used in the 1950s
it was used widely to control the threat of malaria in many countries
What happened in 1960s because the use of DDT
scientists began to notice signs of trouble from DDT in animals that fed on insects. they began to die where DDT has been sprayed, such as beneficial insects like bees also died
what specific thing did scientists notice in the use of DDT in organism
it accumulated in the fat of organisms, and they were further alarmed because it did not break down in organisms
where did DDT stay for thousands and thousands of years
in the environment for many years
how would DDT have spread to areas where it was not sprayed?
as it does not degrade, DDT will have the opportunity to move in the air and through migration in the water that flows
How did high predatory animals accumulate high amounts of DDT in their bodies?
as predators they consume DDT from other animals
what problem did Predatory birds face when they had high levels of DDT?
they produced eggs with abnormal shells that cracked before the babies were ready to be born and many offspring died
what is biological magnification
when chemicals (toxins) are concentrated as they move up the food chain
what is bioaccumulation
when chemicals inthe body can’t be broken down so they accumulate in tissues overtime
give two reasons why banning DDT is a probelm for malaria ridden countries
- people will be in hospitals and increase the risk of malaria
- health care and economics
what is pesticide resistancy? why is this a problem?
being resistant means not being able to hurt you
for the insects there was a new population of resistant insects that will be alive and thats a problem because the insects are not dying.
when acid and base add they create
water and a salt
