Understanding Nutrition, Stimuli, and Reproduction in Living Organisms
Nutrition in Living Organisms
Living things need energy to keep the body functioning and to produce substances for growth and development. This energy is obtained from external sources; the collection of nutrients is food.
Autotrophic Nutrition
This type of nutrition is found in plants, algae, and many bacteria. Autotrophic organisms can produce their own food (organic matter) from simple substances like water and carbon dioxide (inorganic raw materials) obtained from the environment.
Heterotrophic Nutrition
This type of nutrition is carried out by animals and other organisms that obtain food from other beings because they cannot produce it themselves, as plants do. That is, they feed on organic matter.
Processes in Heterotrophic Nutrition
The mechanism of nutrition in heterotrophic organisms involves several processes:
Digestion
The process by which ingested food is transformed so that the body can use it as nutrients.
Circulation or Transportation
The transport of digested substances, the end nutrients, to all parts of the body. Many organisms have a means of transporting nutrients, such as blood.
Respiration
Organisms take oxygen from the air, which is transported throughout the body. Oxygen combines with food to produce energy. This energy can be used for many activities (growth, movement, storage, reproduction, etc.).
Excretion
All these processes produce waste that must be disposed of by the body. Excretion is the process through which the body expels this waste.
Interaction with the Environment
Living organisms depend on and are closely linked to their environment.
The environment continuously sends messages in the form of odors, temperature changes, vibrations, noises, chemicals, environmental humidity, etc., containing information. This set of messages is called stimuli. Faced with these stimuli, organisms must react and respond. To capture stimuli, animals possess senses such as sight, smell, etc. To process information and prepare a response, they have a nervous system.
The survival of any living being depends on being able to capture these stimuli and react appropriately.
Reproduction
Living organisms have the ability to originate new individuals of their own species. This is called reproduction and aims at the perpetuation of the species. In nature, there are a variety of reproductive mechanisms, which can be grouped into two broad categories: asexual reproduction and sexual reproduction.
Asexual Reproduction
This occurs when new individuals arise from a single specialized cell (such as spores) or a fragment of an organism. It is a form of reproduction in which only one individual is involved.
Sexual Reproduction
In this case, reproduction occurs from two specialized sex cells, gametes, which unite to form a new being. In the vast majority of cases, the gametes belong to two different individuals, male and female. However, sometimes the same individual possesses both sexes. In these cases, we speak of hermaphrodite organisms, such as earthworms or many flowering plants.
Other Definitions
Unicellular: Consisting of a single cell.
Multicellular: Consisting of more than one cell.
Scientific names are written in Latin.