Difference Between Plants and Humans

The difference between plants and humans are highly evident. However, both groups of living organisms are made up of similar cellular components. Eukaryotic cells have genetic material within their cellular nucleus and are the basic unit of plants and humans. In fact, both groups of living things have descended from unicellular nucleated organisms, called protists. Through time, these protists evolved into multicellular organisms to which plants and humans now belong.

Because of this common origin, plants and humans also share similar internal components. First, both contain cell membranes, which are the outer boundary of the cell. This cellular structure limits chemicals and other substances that can enter into the cell. Another structure that is common to both plants and humans is the presence of a mitochondrion. This organelle is often referred to as the “powerhouse” of the cell because it provides chemical constituents that are used for cellular metabolism. Lastly, both plants and animals have a nucleus, wherein DNA is stored. Despite all these similarities, why do plants and humans look so different? This article will discuss the differences between plants and humans based on scientific research.

Structural differences

Cell Wall

In addition to a cell membrane, plants have a specialized cell wall. This is composed of cellulose, a dense substance with multiple units of sugar. Because of its dense characteristic, this enables plants to appear rigid and sturdy. In contrast, human cells do not have a cell wall and are less rigid than plant cells.

Cell Shape

Plants are composed of a homogenous group of cells, which are rectangular in shape. Humans on the other hand, have various cell shapes in different parts of the human body.

Vacuole

A vacuole is a special organelle wherein cellular food is stored. Compared to humans, plants have a single large vacuole, which is centrally located. It occupies majority of the cell. This is the reason why plants are able to store water. Humans also have vacuoles, but not as prominent as what plant cells have.

Chloroplast

Plants have a specialized organelle called chloroplasts. This cellular structure enables plants to derive its energy source from sunlight through a process called photosynthesis. This is the most significant difference among plants and humans because humans do not contain chloroplasts. Plants are capable of making their own food, while humans depend on other living things for survival.

Centrioles

Centrioles are special cellular organelles that are composed of the tubulin protein. This is an important structure that functions for cellular replication. Human cells have centrioles, while not only a few plant species possess this organelle. Higher forms of plants, such as flowering plants and conifers do not have a centriole. Examples of plants with centrioles include moss and liverworts.

Vascular tissue

In humans, vascular tissue is composed of blood vessels such as arteries, veins and capillaries. These structures function to carry blood to different parts of the body to function for cellular metabolism. In contrast, plants do not have blood and blood vessels. Vascular tissue in plants is comprised of xylem and phloem. Xylem is an elongated, rigid-walled and tubular structure that transports water and nutrients from roots to branches and foliage. Xylem can be seen in plant barks, flower stems and tree trunks. Phloem, on the other hand, is an elongated tubular structure that similarly function to transport nutrients from the sap to different parts of the plant.

Lysosomes

Lysosomes are special organelles that functions to dispose unwanted substances within the cell. Aside from this, lysosomes have important functions in cellular metabolism, such as cellular digestion and protein synthesis. Compared to plants, lysosomes are important parts of the human cell for survival. In fact, humans with dysfunctional lysosomes develop an illness, called lysosomal storage disease, wherein toxic materials build up within the body. This form of illness threatens human survival. On the other hand, plant cells do not have lysosomes. Plant waste products, such as excess carbon dioxide and water evaporate through the stomata of leaves.

Locomotion

Natural plant habitats range from woodlands, grasslands, heathland and wetlands. Compared to humans, plants are confined to a singular habitat because they do not have any organs for locomotion. Humans, on the other hand, have a specialized nervous and muscular system that both used for mobility. Majority of humans live on landforms, although there are some groups of people who have built houses on lakes and other bodies of water.

Summary

Plants and humans are eukaryotic multicellular living organisms that both evolved from unicellular protists. Because of this, they share similar structural characteristics, wherein their cells have a nucleus, cellular membranes and a mitochondrion. However, they also have specialized cellular structures that are unique for their survival. The most important difference between plants and humans is the presence of a specialized organelle in plants, called chloroplast. This enables the process of photosynthesis, wherein plants are able to manufacture their own food for survival. On the other hand, humans do not have a chloroplast, and they are unable to make their own food for survival.

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