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  • How did plant and animal species originate?

    How did plant and animal species originate?

    Species originated because plants and animals always adapted to the ever-changing environmental conditions. The naturalist Charles Darwin discovered this in the middle of the 19th century. The term 'survival of the fittest' outlined his theory that only those plants or animals that could adapt to the changing environment would survive, reproduce, and over time create new species. Those unable to adapt would become extinct. The ecological niche of an organism describes how that particular individual 'fits' into its ecosystem. For survival, each plant and animal needs to identify and retreat to its ecological niche. Now that we know how species originated, we can breed new species.


    endemic

    What is an 'ecological niche'?

    The ecological niche describes a way of living that provides a species with adequate nutrition, an optimum environment, and as few enemies as possible. For instance, several different species of water birds can live together peacefully on the sea because each species prefers a different food or hunts for its food at different depths in the water. The birds do not prey on each other's food, and hence are not natural enemies. We can also say that this particular animal species has become specialized.


    Who was Charles Darwin?

    Charles Darwin (1809-1882) was a British naturalist. At a time, when people still believed that each living creature was created by God, he began his research on finches on the Galapagos Islands to the west of South America. He found that all finches originated from a single species. This turned the prevalent picture of nature as God's creation upside down and he faced a lot of opposition from the Church. However, his theory was accepted quickly by his colleagues, and when he published his 'theory of evolution, the book was quickly sold out.


    duck

    These four species of ducks inhabit one ecological niche. The wild duck dabbles in the shallow water near the banks, the pochard searches for its food a little deeper, and the tufted duck hunts for snails and shells to a depth of 6 m. In contrast, the goosander eats fish and hunts in open water.


    Why do environmental conditions change?

    There are many reasons for changes in the environment. Environmental change can be sudden because of a meteorite impact or a volcanic eruption or it can be gradual like a change in the climate. In the history of the Earth, there have been many sudden changes. Dust clouds and pollution darken and poison the world and cause catastrophes. Slow changes in the environment such as changes in the sea level, ice ages, or torrential rains can be due to different reasons. For instance, parts of the earth are lifted as a result of the displacement of tectonic plates and therefore sea coasts shift. Today, the environmental changes are mainly due to irresponsible human actions such as draining of marsh areas, cutting of trees, and air pollution.


    Why do we need to breed new species?

    Fruit farmers try to grow good looking apples or those resistant to diseases. The aim is to prevent crop failure and earn more money. Even in animal breeding, the attempt is to breed animals which provide more milk or meat. This is achieved, for instance, by 'crossing' two species with each other. By cross breeding a good milk-yielding cow with a weather-resistant bull, we can get a hardy, weather-resistant milking cow. We can also try to save endangered species by breeding them in zoos.




  • in Venezuela 1000 m high table mountains protrude from rainforests like islands? Most of the plant species grow only on the platforms of the mountains.
  • skylarks sing the whole day to survive? Poor singers are killed by the birds of prey.
  • a high-yield cow gives around 50 kg of milk every day, although just 8 kg is enough to feed a calf?

  • What does 'survival of the fittest' mean?

    'Survival of the fittest' describes the evolution theory of Charles Darwin. In the struggle to survive, the species that are healthy, strong, and have adapted themselves best to their environment will win. They ensure their survival through healthier genetic material that is passed on to their offspring. Thus, a giraffe with a longer neck can reach leaves high on the trees to feed himself. While a giraffe with a shorter neck may stay hungry, since he has access only to the leaves lower on the tree. Eventually, the hungry giraffe may become so weak that he falls prey to lions.


    giraff

    The giraffe's long neck evolved because of competition for food with other animals.




    Try being a breeder


    You need: Two cacti of different species (a column cactus and a spherical cactus), rubber bands, garden gloves, a sharp, clean knife
    Do as follows: Wear the gloves and cut both cacti about 1 cm above the soil. Place the head of the spherical cactus on the base of the column cactus. Fix it in place by putting rubber bands around the head of the 'cactus stack' and the pot containing the cactus. Do not water the cacti and wait for 1-2 weeks.