digestion

• • what is animal nutrition

  the process by which food is taken in for make use in different body functions
• Animal nutrition is the process by which food is taken in for use in different body functions.
• Typically, food is broken into smaller molecules and absorbed prior to utilization.
• Animals are heterotrophs.
• Commensalism is a close association between two living organisms of different species which is beneficial to one and does not affect the other, neither harmful or beneficial.
• Barnacles attached to whales are an example of Commensalism.
• Tapeworms and humans, Lice and humans are examples of Commensalism.
• Heterotrophic nutrition is the process by which the organisms obtain organic food molecules by ingesting other organisms or by substances derived from other organisms.
• Other than animals, fungi and majority of bacteria are heterotrophs.
• There are two types of heterotrophic nutrition namely, holozoic nutrition and symbiosis.
• Holozoic nutrition is the most common mode of nutrition where animals ingest food into their alimentary canal.
• Holozoic nutrition consists of five main stages: Ingestion, Digestion, Absorption, Assimilation, and Elimination/Ejection.
• Ingestion is the first stage in holozoic nutrition where the act of eating or feeding happens.
• Food sources differ among animal species and they possess different modes of ingestion according to the diet or environment.
• Digestion is the second stage in holozoic nutrition where food is broken down into molecules small enough to pass through the membranes and enter the cells of organisms.
• Digestion could occur mechanically (by teeth or muscle contractions) and chemically (by enzymes).
• During mechanical digestion, food is broken down into smaller fragments thus increasing the surface area for efficient chemical digestion.
• During chemical digestion, enzymes break bonds in large molecules into small molecules.
• The last two stages of food processing occur after the food is digested.
• Absorption is the stage in holozoic nutrition where the animal's cells take up small molecules such as simple sugars and amino acids.
• Assimilation is the process of utilization of absorbed nutrients for various functions of the body.
• Fluid feeders suck nutrient-rich fluid from a living host using well-adapted mouth parts.
• Bulk feeders are animals which eat comparatively large pieces of food.
• Mutualism is a cose association between two living organisms of different species which benefits both partners, such as cellulose digesting microorganisms in Ruminants and Termites.
• Filter feeders strain suspended food particles from the surrounding watery medium using mechanisms such as capturing, trapping, etc.
• Inside the gills of filter feeders, cilia sweep the food particles to the animal's mouth in a film of mucus.
• Maggots (fly larvae) are an example of substrate feeders, burrowing into animal carcasses.
• Filter-feeding clams feed by filtering particles and food in the water.
• Substrate feeders live inside their food source or on the food source, eating its way through the food.
• Examples of filter feeders include clams and oysters which feed on small pieces of food in the water that passes over their gills.
• The leaf miner caterpillar is an example of a substrate feeder, eating through the soft tissues of a leaf.
• Bulk feeders have different types of adaptations to tear the food or to capture the prey, such as jaws, teeth, tentacles, claws, poisonous fangs.
• Parasitism is a cose association between two living organisms of different species which is beneficial to one (parasite) and harmful to the other (host), with parasites living either within or on the host and deriving its nourishment.
• Symbiosis is an ecological relationship between organisms of two different species that live closely together, divided into three groups: Mutualism, Parasitism, and Commensalism.
• Examples of fluid feeders include mosquitoes which suck human blood, Aphids which suck phloem sap of plants, and Bees and hummingbirds which suck honey from flowers.
• Elimination/Ejection is the process where undigested materials are passed out from the alimentary canal.
• Coordination


  Between stimuli and responses needed to maintain constant internal environment inside the body of an organism for existence
• Systems contributing to coordination

  • Nervous system
  • Endocrine system
• Animals unlike plants have two different but related systems for coordination of body function
• Nervous system and endocrine system

  • They are the two systems for coordination of body function in animals