Lecture 4 - Feeding part 1: Invertebrate feeding patterns Flashcards
Fundamental ways to obtain food
Herbivory
Carnivory
Detritivory
Symbiosis
Autotrophs
Synthesize complex molecules from simple inorganic substances
Heterotrophs
Obtain energy by consuming other organisms
Food materials
Plant
Animal
Symbiosis
Digestive systems
No gut cavity
Gut cavity present
Basic feeding modes
Deposit feeding
Suspension feeding
Plant material as food
Low quality
Low assimilation efficiency
What do animals require to eat plant material
Ability to bite and chew
Space and time
Special enzymes
Animal material as food
High quality
High assimilation efficiency
What do animals require to eat animal material
Sophisticated feeding strategies
Symbionts and their products as food
Host must accommodate the symbiont
How is very small food eaten?
Endocytosis followed by intracellular digestion
How is larger food eaten?
Digestive system
Extracellular digestion
No gut cavity
Food engulfed by endocytosis e.g., protozoans and sponges
Gut cavity
Some digestion by enzymes in gut
Ingest larger food masses
Greatly increase surface area for absorption
Types of gut
Simple sac-like gut
Tube-like gut
Simple sac-like gut
Single opening - 2-way flow
e.g., flatworms
Tube-like gut
Two openings, mouth and anus - 1-way flow
Allows specialisation of gut regions
Protozoans food sources
Deposit feeders Filter feeders Parasites Carnivores Herbivores
Filter feeder (Sponges)
Perforated tube
Small current created by choanocytes
Intracellular digestion
Carnivores (Cnidaria)
2-way sac-like gut
Intracellular and extracellular digestion
Capture prey using Cnidae
Cnidae used to sting or adhere prey
Flatworms (Carnivores and detritivores)
2-way sac-like gut Pharynx Wrap around prey or entangle in slime Food swallowed whole or in pieces Digestion first extracellular then engulfed
Platyhelminthes (flukes and tapeworms) - Parasites
No gut cavity
Neodermis and glycoproteins
Attachment using hooks/suckers
Annelids - segmented worms
True coelom
1-way gut
Wide range of feeding styles