This topic contains a solution. Click here to go to the answer

Author Question: Which of the following categories includes manatees and dugongs? A) Cetacean B) Cnidaria C) ... (Read 46 times)

fox

  • Hero Member
  • *****
  • Posts: 540
Which of the following categories includes manatees and dugongs?
 A) Cetacean
  B) Cnidaria
  C) Sirenia
  D) Teleost

Question 2

What is DDT? What affect did it have on the population of brown pelicans in the 1960s?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

adf223

  • Sr. Member
  • ****
  • Posts: 304
Answer to Question 1

C

Answer to Question 2

 DDT is a chlorinated hydrocarbon. It was used as a pesticide until it was discovered it was causing damage to the ecosystem.
 The damage caused by DDT was high due to biological amplification. This occurs when levels of synthetic chemicals increase and concentrate into the flesh of organisms in higher trophic levels. The DDT began in plankton, but became stronger in concentration as the food web reached the brown pelican.
 The brown pelicans began to decline in number because the DDT softened the shells of the eggs. The eggs would crack before a chick would hatch. Then the adults would abandon the nest. The population declined rapidly.
 Rachel Carson wrote the book Silent Spring which discussed this very case in a way that was easy for everyone to understand. She began environmental activism and conservation in a way. She definitely changed the perspective about the impacts of humans on ecosystems




fox

  • Member
  • Posts: 540
Reply 2 on: Aug 22, 2018
Thanks for the timely response, appreciate it


frankwu0507

  • Member
  • Posts: 322
Reply 3 on: Yesterday
Excellent

 

Did you know?

Amphetamine poisoning can cause intravascular coagulation, circulatory collapse, rhabdomyolysis, ischemic colitis, acute psychosis, hyperthermia, respiratory distress syndrome, and pericarditis.

Did you know?

Looking at the sun may not only cause headache and distort your vision temporarily, but it can also cause permanent eye damage. Any exposure to sunlight adds to the cumulative effects of ultraviolet (UV) radiation on your eyes. UV exposure has been linked to eye disorders such as macular degeneration, solar retinitis, and corneal dystrophies.

Did you know?

The B-complex vitamins and vitamin C are not stored in the body and must be replaced each day.

Did you know?

Never take aspirin without food because it is likely to irritate your stomach. Never give aspirin to children under age 12. Overdoses of aspirin have the potential to cause deafness.

Did you know?

Congestive heart failure is a serious disorder that carries a reduced life expectancy. Heart failure is usually a chronic illness, and it may worsen with infection or other physical stressors.

For a complete list of videos, visit our video library