Video Transcript
What are the two major types of nutrition? (A) Autotrophic and heterotrophic. (B) Autotrophic and phototrophic. (C) Heterotrophic and chemotrophic. Or (D) chemotrophic and phototrophic.
This question asks us to identify the two major types of nutrition. You’ve probably heard the word “nutrition” used before in the context of food. More specifically, nutrition is the assimilation of food materials by living
organisms, referring to how all living things take in and use nutrients to gain
energy and essential molecules for our various life processes. There are very diverse ways that organisms can obtain their nutrition, so let’s
review a few examples to try and answer this question.
The major ways that organisms obtain their nutrition can be divided into organisms
that are capable of synthesizing organic matter themselves from simple inorganic
materials and those that rely on consuming other organisms or organic matter. Humans are an example of organisms that rely on other living or once-living organisms
to obtain our nutrition. Everything we eat, whether it is plant matter like fruit and vegetables, fungal
matter like mushrooms, or animal matter like meat and fish, was once a living
organism.
We classify organisms that obtain their nutrition in the form of organic matter from
another living or once-living organism as heterotrophic. The prefix hetero- means different, and the suffix -trophic means food, describing
how heterotrophic organisms obtain their food by consuming other different living
organisms or the organic matter from other once-living organisms. There are plenty of other examples of heterotrophs. For example, bees feed on the sugar in nectar that is produced by a plant, another
living organism.
Now, let’s take a look at the other major type of nutrition. Most plants need light, inorganic materials like carbon dioxide, and water and
minerals that they can absorb from soil. These plants are described as autotrophic organisms. The prefix auto- means self, describing the fact that autotrophic organisms are able
to produce their own food in the form of sugars. Organisms that can obtain nutrition using light like most plants do in this way are
called phototrophs or sometimes photoautotrophs. The prefix photo- means light, indicating that these organisms use photosynthesis to
synthesize, or produce, sugars using light energy and simple inorganic
materials.
There are other examples of autotrophs, such as chemotrophs, sometimes called
chemoautotrophs. The prefix chemo- refers to chemicals, describing how chemotrophs like certain
bacteria can convert chemicals in their environment that are often toxic to other
organisms into sugars that they can use in cellular respiration to release
energy. As phototrophic and chemotrophic nutrition are both examples of autotrophic nutrition
and are not the two major types, we can eliminate options (B), (C), and (D). We can also deduce the correct answer to this question. The two major types of nutrition are (A) autotrophic and heterotrophic.
