1. Bellwork: How are humans adapted for the diet that we eat?

2. Animal behavior
27.1 Feeding and digestion

3. What different ways can animals obtain food?
All animals are heterotrophic
There are 5 different ways that animals can obtain food
Filter Feeders
Detritivores
Carnivores
Herbivores
Nutritional symbionts

4. What do filter feeders eat?
Often Algae and small animals, plankton etc….
They often utilize modified gills or structures like nets
Invertebrate filter feeders are often small or colonial
Spend their adult life in one spot
Larger filter feeders, such as a whale shark, will feed whilst swimming

5. What is Detritus?
Detritus is made up of decaying bits of plants and animal material
Detritivores feed on detritus
Energy is also obtained from the bacteria, algae and other micro-organisms that grow on and around it
Example – earthworm
Often essential component of an ecosystem

6. How do carnivorous invertebrates catch their food?
Through poison tipped darts or venomous fangs
All carnivores eat other animals
Often utilize teeth, claws, speed and/or stealth to bring down prey

7. How can a herbivore live on such a simple diet?
Animals need complex digestive systems to live on just leaves/grass
Due to low nutritional content
Can contain poisons
Hard parts can damage teeth
Some herbivores live on nuts, seeds and fruits
Many mammals and birds
High energy compounds

8. What does symbiosis mean?
Dependency of one species on another
A symbiont is an organism involved in symbiosis
Parasitic Symbionts
Within or on host organism
Some simply nuisance, some cause serious disease
Mutualsitic Symbionts
Both participants benefit
What examples can you remember?

9. How do animals process food?
By either intracellular or extracellular digestion
Intracellular
Food digested in specialized cells that pass nutrients to other cells by diffusion
Example - sponge
Extracellular
Food broken down in digestive system not specific cells
Food can then be absorbed and nutrients taken where they need to go

10. Extracellular digestion explained…
Gastrovascular cavities
Single opening for food ingestion and expelling of wastes
Cells lining the cavity will secrete enzymes and absorb digested food
Other cells surround food particles to digest them
Nutrients transported to cells in the body
Digestive tracts
Many invertebrates and all vertebrates have a digestive tract – two openings
Specialized structures perform different tasks – stomach, intestine etc..
Solid waste disposal
Some indigestible material will always be left – must be expelled

11. How are mouth parts adapted for different diets?
The mouthparts and digestive systems of many different organisms have evolved many adaptations to different food types
Eating meat
Designed to capture food, hold it, and slice/dice
Eating plant leaves
Adapted to rasping/grinding

12. How can digestive tracts be specialized?
Carnivorous invertebrates typically have short digestive tracts that produce fast acting, meat-digesting enzymes
No animal produces enzymes for breaking down cellulose
Some herbivores have very long intestines or specialized pouches for harboring microbial symbionts
Cattle have a pouchlike extension of their esophagus, called a rumen
Where symbiotic bacteria digest cellulose
Animals with rumina (like cattle) often regurgitate partially digested food and ‘re- chew’

13. Key Points questions What is a nutritional symbiont?
How would a coral be affected if all of its symbiotic algae die?
What are the two types of digestion that animals use to breakdown and absorb food?
What are the major differences between gastrovascular cavities and digestive tracts?
What is the relationship between a ruminant and its microbial symbionts?