Plants are the only living thing on Earth that sustains all of life. They make up a vast area of this planet, although the area covered by plants decreases daily. All organisms are made of cells. Are plants any different?
Yes, plants are multicellular organisms. Although unicellular plants also do exist. They are few in comparison to the wide array of multicellular plants. Multicellular plants are a result of evolution. These reproduce slower than unicellular ones, but they expand and take up more space. These are also more beneficial to the environment.
Plants are spectacular species. Some plants amaze you, but then there is another plant to amaze you more. Let us learn more about the nature of plants.
What Are Plants?
Plants have provided us with shelter and food since the world’s inception. They have also been habitats for many organisms and have sustained their populations. Plants happen to be the only organisms that are independent and make their own food. They only rely on the providence of air, water, and sunlight.
Types Of Plants
Most of the plants that we see are big, visible, and green. However, plants extend to all types. Let us discuss the two major distinct types of plants.
Unicellular Plants
As the name suggests, these plants have “uni” cells; “uni” means one. They are single-celled. This one cell is responsible for all the major functions of the plant. These major processes include homeostasis, reproduction, and metabolism. The cell also gets energy, uses energy, regulates waste, and transports materials. Most unicellular organisms cannot be seen by the naked eye, so a microscope is needed. An example of a unicellular plant is algae. The naked eye can see algae, but that is because multiple algae stay together, making it easier to view.
Multicellular Plants
As is evident, a multicellular plant consists of multiple cells. The number of cells that combine to form plants can vary across the categories and sizes of plants. This type of plant is visible to the naked and can be larger than most humans or expand over meters. These plants make their own food and ensure their own survival. The reproductive parts of the plants are the flowers.
Specialization Of Cells
In multicellular organisms, there are thousands to millions of cells exist. A plant in itself could have multiple different multicellular parts or organs. Due to this, each cell has been designated to do a specific job.
The process is often also referred to as cell differentiation. Specialization of cells occurs after cell division. Each cell is distinguished based on the function that it is assigned. In the plant, stem, leaves, and root cells are the most commonly known specialized cells.
For example, root cells are specialized to carry out functions specific to the root. They absorb water and minerals from the soil. Stem cells are specialized to transport these nutrients and water. They also play a role in photosynthesis.
Reproduction In Multicellular Plants
Asexual Reproduction
Asexual reproduction does not involve the use of the reproductive parts of the plant that aid the reproductive process. Some ways that this occurs are as follows:
- Vegetative Propagation – This is when new plants grow from the already existing plant. It usually grows from the vegetative part of the plant; hence, the name of the process.
- Budding – A bud is formed from the already existing cell. The bud eventually leaves the cell and becomes an entity of its own.
- Fragmentation – This is when a plant is divided due to reasons, and then the two parts grow on their own as singular organisms.
- Spore Formation – Spores float in the air and begin growing in an adequate environment
Sexual Reproduction
The steps of sexual reproduction are as follows:
- Pollination – The pollen grains fall on the stigma of a similar flower
- Fertilization – After the fusion of gametes, a zygote is formed.
- Fruit formation – The ovary is the fruit.
- Fruit dispersal – Animals or insects carry the fruit around and disperse it for further reproduction.
Here is a video on sexual reproduction in plants: https://www.youtube.com/watch?v=HP21hIVJhWI
Evolution Of Plants
Plants have been around for the longest time before humans walked this land. Several questions are posed as to why two different types of plants came into existence. Were unicellular plants not enough?
To answer this question, there are evolutionary explanations. In environments where the only survival ensured was that of the fittest. Examples of animal evolution in animals due to the need for survival are scattered across books. For example, it is reported that birds learned to fly as a consequence of evolution in order to survive.
Similarly, plants had to adapt to the competitive environment as well. While unicellular plants fared well, they were not specialized enough to carry out functions adequately. As a result, cells grouped together and delegated certain functions to each cell. This resulted in cell specialization and has made the survival of plants through the centuries possible.
The threat to the survival of plants was predation. Another reason for evolution was to grow and expand. Every living wants to expand through spaces and integrate. Plants did the same and succeeded after being multicellular.
Why Do Unicellular Plants Still Exist?
The number of unicellular plants is relatively low, but they still do exist. One thing that is important to understand is that each organism plays a role in the ecosystem. Unicellular plants have existed for a purpose and have not been threatened. An example of a unicellular plant is algae. This is not prey, and so has fared well.
Final Thoughts
Plants are multicellular, but unicellular plants also exist. Plants evolved into multicellular plants from unicellular ones as they were faced with a need to survive, reproduce, expand, and integrate successfully into the environment. Groups of cells joined together to form multicellular plants, which later developed cell specialization to run survival processes efficiently. They also formed complex reproductive systems for expansion. The evolution of plants did not completely erase unicellular plants.
