HOW THE FIRST PLANTS AND ANIMALS EVOLVED AND BECAME DEPENDENT ON EACH OTHER

Plants are the living organisms that grow in the earth and have a stem, leaves and roots. They play an important role in the cycle of nature and without them; there could be no life on the earth. Plants are the primary producers that maintain all life forms or other living organisms on earth. They manufacture their own food during the process of photosynthesis.

Animals refer to any living organisms that are not plant including people. Animals cannot manufacture their own food; they depend on plants both directly and indirectly for their survival, meaning that in order for them to get their food; they have to depend on plants. All animals and the food that they eat can be traced back to plants ( Kazlev, 2002).

During the process of photosynthesis, "plants take energy from the sun and carbon dioxide from the air". They also take water and minerals from the soil and give off water and oxygen. Human beings or animals breathe the oxygen which comes from the plants. Animals and other non producers take part in the process of respiration. Respiration is "the process whereby oxygen is used by organisms to release energy from the food and carbon dioxide is taken out". The process of photosynthesis and respiration help to maintain the natural balance of oxygen, carbon dioxide and water from the earth (Kazlev, 2002).

The leaves of the plants absorb energy from the sun and turn water and carbon dioxide into sugar and starch. "Sugar and Starch provide plants with energy to grow and they also reduce flowers and seed and carry on their other life processes". Most of the animals prefer the leaves of the plants. Plants and animals are complex organisms made up of cells. Plant cells have "thick, rigid walls that consist of cellulose and cells of animals do not have thick as well as rigid walls". Plants need heat from the sun to grow and the climate of the area also plays an important role in the growth or survival of the plants (Kazlev, 2002).

Prokaryotic are the plant fossils known as bacteria. They feed themselves on "the chemicals which are found inside of the water and they are heterotrophy meaning that they do not use sunlight to manufacture their own food, so they eat their food rather than producing the food". They convert food such as sugar into alcohol to get their energy. There is no nucleus inside the cell of prokaryotic organism. Animal fossils are known as a eukaryotic, which means that their cells do not have nucleus (Kazlev, 2002).

Blue green algae are the plants that are found inside the water or ocean. They use sunlight to manufacture their own food and they also create oxygen. They fill the atmosphere with oxygen. Other organisms need oxygen to carry out their life process of growing, feeding, responding, reproducing and they also produce carbon dioxide and the algae also need carbon dioxide to perform their life processes (Kazlev, 2002).

Living organisms are classified as consumers which are animals, producers which are plants or decomposers which are fungi, depending on how they get food. Animals that feed on plants are known as herbivores such as goats and they are called primary consumers. Carnivores like lion are animals that feed on meat and omnivores are animals that feed on both plants and animals, e.g.: human and baboons (Kazlev, 2002).

Environmental limiting factors such as temperature, water, light, competition and soil contribute on the survival of both plants and animals. So every organism needs certain requirements for their survival. Sunlight and rainfall affect plant growth. These two limiting factors can help the plant to grow well and animals leave the habitat where there are a lot of plants so that they can hide themselves from their energy.

Reference:

1. Kohler, S. Plants, [Internet] 2006 May 8, 14:30. UTC [cited 2006 May 07]. Available from: http://www.blueplanetbiomes.org/plants.htm

2. Kazlev.A.M. 2002, PLANT,(land plants) [Internet] 2006 May o8, 14:00.UTC [Cited 2006 May 07, 10:12]. Available from:
http://www.plalaeos.com/plant/default.htm



Lizzy Maluleke
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