Body design of animals

Question 1

Factors correlated with body design

Answer 1

1. Environments (Es)
2. Body size
3. Mode of existence
4. Constraints of the genome - limitation by ancestral design

Question 2

Marine E

Answer 2

Diverse habitats:
•eulittoral zone - rock pools
•deep sea hydrothermal vents
•coral reefs
•photic zone where light reaches, algae and plants live
•aphotic zone - less abundant food sources

Question 3

Advantages of the sea

Answer 3

• lots of space
• high productivity - more around shores, and shallow water (light and run offs from land)
• coastal upwellings - nutrients
• sea temp keep constant, temperate changes with seasons (not so great in tropics)
• isosmotic with body fluids of many = can have simple structures
• buoyancy - supports huge animals
• fertilisation and development
• produce waste as ammonia

Question 4

Freshwater

Answer 4

• less constant temp and o2
• requires osmoregulation
• turbidity, velocity and volume can change - freezing, drying
• still provides support for body
• eggs retained in parent or attached to bottom on water
• waste as ammonia

Question 5

Estuarine

Answer 5

• marine can tolerate FW or vice versa
• productive Es
• often very silty (run off from land)
• seasonal variation in salinity
• provides support
• waste as ammonia

Question 6

Terrestrial

Answer 6

• problems with preventing water loss
• no external fertilisation - gametes need to be protected
• excrete urea or uric acid
• daily and seasonal temp variation

Question 7

Size of animal

Answer 7

• body size increases - SA:V decreases
• smaller can rely on diffusion - problem of water loss
• larger animals require other mechanisms like waste, oxygen transport etc.

Question 8

Mode of existence

Answer 8

•free-moving 
-bilaterally symmetrical 
-cephalisation
•attached/sedentary 
-radially symmetrical 
-NS distributed around body