Topic 4 Ecology: Interactions between Organisms and their Environment

Question 1

1. Freshwater fish: these fish live in a hypo-osmotic environment which causes an excess intake of water. Thus, the fish seldom drink and excrete dilute urine
2. Saltwater fish: live in a hyper-osmotic environment. The fish are constantly drinking and excreting salt across their gills
3. Arthropods: secrete solid uric acid crystals to conserve water
4. Plants: possess waxy cuticles on the leaf surface and stomata. Stomata are on the lower leaf surfaces only. Leaves are shed in winter. Desert plants have have extensive root systems, fleshy stems, spiny leaves, extra thick cuticles, and few stomata

Answer 1

Osmoregulation

Question 2

1. Cold-blooded (poikilothermic): vast majority of plants and animals are poikilothermic. This means their body temperature is close to that of their surroundings, so their metabolism is radically affected by the environmental temperature
2. Warm-blooded (homeothermic): homeothermic organisms make use of the heat produced by respiration. Physical adaptations like fat, hair, and feathers retard heat loss. Mammals and birds are warm-blooded

Answer 2

Thermoregulation