Mode of Nutrition

• Calories- a measure of the energy content in food.
• Nutritional Requirements of

  Animals:

  1. Carbohydrates
  2. Proteins
  3. Fats
  4. Essential Nutrients
• Carbohydrates- Provide energy, broken down into glucose for cellular

  activities.
• Proteins: Essential for tissue building, repair, and enzyme synthesis,

  sourced from dietary amino acids.
• Fats: Supply concentrated energy, aid in vitamin absorption, and

  maintain cell structure.
• Essential nutrients: Including amino acids, fatty acids, vitamins, and

  minerals, crucial for proper physiological function.
• Cells uptake nutrients through:

  1. Phagocytosis
  2. Pinocytosis
  3. Receptor-mediated endocytosis:
• Phagocytosis: Engulfing large particles for digestion.
• Pinocytosis: Absorbing fluids and solutes into small vesicles.
• Receptor-mediated endocytosis: Selectively taking in molecules

  bound to receptor proteins on cell surfaces
• Different Types of Animals Based

  on Feeding Mechanisms

  1. Substrate-Feeders
  2. Filter-Feeders
  3. Fluid-Feeders
  4. Bulk-Feeder
• Substrate-Feeders: are animals that live on or inside their food source, consuming it as

  they go along.
• Filter-Feeders: are animals that catch small food particles by filtering them from water

  or air using special structures.
• Fluid-Feeders: are animals that consume liquid nutrients. They typically feed by sucking

  fluids from their prey or food sources.
• Bulk-Feeders: are animals that consume large pieces of food, often swallowing them whole

  or in large chunks. They usually have adaptations like strong jaws or specialized teeth for

  tearing and chewing food.
• Different Types of Digestive

  Compartments in Animals

  1. Food vacuoles in unicellular organisms:
  2. Gastrovascular cavity or incomplete digestive system:
  3. Complete digestive system:
• Food vacuoles in unicellular organisms: are membrane-bound structures that serve to engulf and digest food particles, aiding in

  nutrient uptake and energy production.
• Gastrovascular cavity or incomplete digestive system: Is a simple digestive and circulatory system found in cnidarians and flatworms. It consists of

  a central cavity with a single opening that serves as both a mouth and an anus. Nutrients are

  distributed throughout the organism

  '

  s body directly from this central cavity.
• Complete digestive system: A system found in all animals where digestion occurs in a specialized digestive tract,

  typically consisting of a mouth, esophagus, stomach, intestines, and anus. This system allows

  for the ingestion, digestion, absorption, and elimination of food through a series of

  specialized organs and structures.
• The Accessory Organs

  1. Liver
  2. Pancreas
  3. Gallblader
• Liver: The liver

  '

  s main job within the digestive system is to process the nutrients absorbed from

  the small intestine. Bile from the liver secreted into the small intestine also plays an

  important role in digesting fat and some vitamins.
• Pancreas: The pancreas secretes digestive enzymes into the duodenum that break down protein,

  fats, and carbohydrates.
• Gallblader: The gallbladder stores and concentrates bile from the liver, and then releases it into the

  duodenum in the small intestine to help absorb and digest fats.
• Nutrients are essential needs for growth and life maintenance, this

  includes vitamins, minerals, carbohydrates, proteins, and fats.
• Autotrophs: Make their own organic nutrients from inorganic sources

  through processes like photosynthesis or chemosynthesis. Examples

  include plants, algae, and some bacteria.
• Heterotrophs: Depend on consuming organic matter produced by other

  organisms for nutrients. They include animals, fungi, and most bacteria,

  which obtain energy by breaking down organic molecules through

  processes like digestion and cellular respiration.
• Herbivores: Eat only plants as their primary source of nutrition. Some examples include cows, rabbits, deer, and horses.
• Carnivores: Consume mostly animal flesh as their primary source of nutrition. Common examples include lions, tigers, wolves, sharks, and eagles.
• Specialized Absorptive Roots

  1. Root Hair
  2. Root Nodules
  3. Mycorrhizae
• Root Hair - Root hair, or absorbent hairs, are outgrowths of epidermal cells,

  specialized cells at the tip of a plant root. They are lateral extensions of a

  single cell and are only rarely branched. They are found in the region of

  maturation, of the root.
• Root Nodules - Plant root nodules are the knob-like structures formed

  especially on and from roots of leguminous plants, as a result of symbiotic

  infection by nitrogen-fixing bacteria such as Rhizobium.
• Mycorrhizae - The word “

  mycorrhiza

  ”

  means fungal root. To be more

  specific, mycorrhizae are fungi that have a symbiotic relationship with the

  roots of many plants. The fungi which commonly form mycorrhizal

  relationships with plants are ubiquitous in the soil.
• Nutritional Adaptation by Plants

  1. Symbiosis of plants and soil microbes
  2. Symbiosis of plants and fungi
  3. Parasitism
  4. Predation
• Symbiosis of plants and soil microbes

  The symbiosis between plants and soil microbes refers to a mutually beneficial

  relationship where both organisms benefit from each other

  '

  s presence.
• Symbiosis of plants and fungi

  The fungi colonize the root system of a host plant, providing increased water and

  nutrient absorption capabilities while the plant provides the fungus with

  carbohydrates formed from photosynthesis.
• 
  

  Parasitism is generally defined as a relationship between the two living species in

  which one organism benefits at the expense of the other.

  The organism that is benefitted is called the parasite, while the one that is harmed is

  called the host.
• Predation is an interaction in which one organism, the predator, eats all or part of

  the body of another organism, the prey. Herbivory is a form of predation in which

  the prey organism is a plant.