Autotrophs & heterotrophs
Autotrophs- called producers. They have the ability to produce their own food. Although plants constitute the majority of autotrophs, some organisms create organic food through a series of inorganic chemical reactions. There are two types of autotrophs:
These are plants containing the chlorophyll pigment, and prepare their own food by acquiring energy from sunlight, and using carbon dioxide and water. Such autotrophs undergo the process of photosynthesis for preparing glucose molecules, and hence are called phototrophs. Most plants, algae, phytoplanktons, and some bacteria, fall under this category.
Some autotrophs obtain energy through a series of chemical reactions, preparing energy-containing organic molecules by converting inorganic substances into energy. They are known as chemotrophs. Some bacteria living in extreme conditions utilize inorganic substances like hydrogen sulfide to generate chemical energy.
Heterotroph-Heterotrophs are also called consumers. They do not have the capacity to produce their own food, and depend on the autotrophs for their survival, either directly or indirectly. Heterotrophs obtain the food molecules prepared by plants and other producers. They consume the food, and use the energy to carry out their metabolic activities. Here are the various types of heterotrophs:
➤ Herbivores, like cattle, deer, and elephants, obtain their food directly from plants.
➤ Carnivores like lion, snakes and sharks, feed on other animals.
➤ Omnivores like humans consume both plants and animals for fulfilling their energy requirements.
➤ Detritivores like earthworms, eat up the remains of dead plants and animals.
➤ Decomposers like fungi, breakdown organic matter by secreting enzymes.
➤ Scavengers like vultures, eat dead animals.