Biology paper 2 possible questions??

Question 1

Succession

Answer 1

• How an ecosystem changes over time (change in species diversity and habitat diversity)
• Relies on environment being made less hostile by present species via death and decomposition leading to it being outcompeted and replaced by larger better adapted species.

Question 2

Describe valves opening and closing

Answer 2

• Pressure keeps blood flowing one way
• Valves prevent unwanted backflow of blood
• Higher blood pressure above valve forces it open
• Lower blood pressure beneath valve
• Lower blood pressure can’t open valve
• Higher blood pressure beneath valve forces it closed -cusps of valve fit closely together

Question 3

Left ventricle

Answer 3

• Pumps blood to the rest of the body
• Thick muscular wall
• Contracts to create enough pressure

Question 4

Unidirectional flow

Answer 4

• Shows that mammals have a double circulatory system

- Blood travels through the heart twice in one circulation of the body

Question 5

Nutrient cycle

Answer 5

• Saprobiontic microorganisms break down producers and molecules when they die - release nutrient in its original simple form