Feeders

FEEDING ADAPTATIONS

Terrestrial plants have tough cell walls (why?) so breaking the cell walls and digesting cellulose are problems to be overcome.
Some animals have symbiotic micro-organisms in their g-i tract that produce cellulase and allow digestion of cellulose into substances their hosts can absorb. E.g. Termites & herbivorous mammals (compare these with locusts and grasshoppers).
Compare terrestrial herbivorous, carnivorous and omnivorous mammals in the following categories: (1) dentition and (2) length and structure of the intestines.Aquatic plants are supported by surrounding water, they have little tough supporting tissues and are easily digested.Thus aquatic herbivores need no special adaptations except that some aquatic plants are tiny and are strained from the water so some of the herbivores aremicrophagous (filter) feeders, e.g. baleen whale, sponges, molluscs, some crustaceans, some birds (e.g. flamingo)
Filter feeding is non-selective, everything which is filtered is ingested, what can be used is digested & the remainder is egested.Macrophagous feedersIncludes animals that have mechanisms for
(a) Ingestion of inactive masses e.g. earthworms and detritus feeders
(b) Scraping, boring, biting, chewing e.g. sea-urchins, snails, insects and vertebrates
(c) Capture and swallowing of prey e.g. fish, snakes, birds, bats
There is an extensive range of modifications for acquiring food (radula, teeth, beaks, fangs)
Fluid feedersHave modifications for piercing or sucking, e.g. some worms (leeches), insects (mosquito), birds (_ _ _ _ _ _ _ _ _ _ _) and mammals (_ _ _ _ _ _ _ _ _ _).