Chemical influences on animal growth

Lead poisoning

• Inhibits the action of some enzyme, e.g. catalase

• Reduces plant growth• Causes learning difficulties in young children• Sources include petrol and lead piping

First symptoms of lead poisoning: vomiting, clumsiness, irritability and

headaches.

• http://news.bbc.co.uk/1/hi/world/asia-pacific/8202429.stm

• http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/7055037.stm

Iron

• Component of : - haemoglobin- many enzymes and

cytochromeShortage leads to anemia

Iron deficiency

Calcium

• Obtained from milk products• Component of shells, bones and teeth• Needed for blood clotting

Vitamin D

• Obtained from milk• Formed in the skin when exposed to sunlight• Promotes the absorption of calcium from the

intestine• Required fro bone formation• Shortage leads to deformed bones in young

children (rickets)

Rickets (Vitamin D deficiency)

• http://www.thachers.org/rickets_photos.htm

Rickets (Vitamin D deficiency)

• http://news.bbc.co.uk/1/hi/england/1936208.stm

Drugs

• Many drugs taken during pregnancy can pass across the placenta and affect the foetus

• -Thalidomide: anti-nausea drug, causes limb deformities

Drugs

• Many drugs taken during pregnancy can pass across the placenta and affect the foetus

• -Thalidomide: anti-nausea drug, causes limb deformities

• Alcohol: may retard growth and mental development. In extreme cases, foetal alcohol syndrome develops

Drugs

• Many drugs taken during pregnancy can pass across the placenta and affect the foetus

• -Thalidomide: anti-nausea drug, causes limb deformities

• Alcohol: may retard growth and mental development. In extreme cases, foetal alcohol syndrome develops

• Nicotine: may retard growth and mental development