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1. For this topic on evolution, I decided to choose spiders. Spiders have apparently been around at least about 300 million to 400 million years. Unfortunately, because there were not as many rocks on land before, there are not as many preserved fossils of arachnids. Spiders originally had an appearance that looked like crabs. Interestingly enough, it was discovered that spiders actually did not have spinnerets before which is how spider webs are made. It is believed that this was because they needed to conserve energy. Also, they began to become smaller which allowed them to be more adaptable to different locations. Depending on the spider, it can live in diverse conditions such as very dry places that not as many other things can live in. Another benefit of its small size was that it was easier for them to be hidden from their predators. It turns out, they actually had a segmented abdomen before evolution started to give them a fused abdomen that spiders we know of today have.
2. Australian lizards are also known as skinks. According to Adam Skinner, a researcher of the University of Adelaide, he states that throughout the last 3.6 million years, the lizard’s body has evolved and changed in order to adapt to the lizard’s lifestyle. Skinks have been dropping their limbs and have become “legless”, like snakes (No Author). This has been mainly due to the fact that the skinks spends a majority of their lives swimming in the soil and sand. Their lifestyle and activities rapidly changed the shape of their bodies and caused their limbs to become meaningless throughout their evolution(Lloyd, Robin). According to Skinner, “It is believed that skinks are losing their limbs because they spend most of their lives swimming through sand or soil; limbs are not only unnecessary for this, but may actually be a hindrance” (Lloyd, Robin). However, they are not the only ones that have been changingin the last centuries. There are about 53 snakes and lizards that have evolved (No Author). These lizards have either lost their limbs or gained a new one in order to adapt to the environment. The environment acts like a filter thatforced them to adapt and their genes changed. This matches the theory of revolution because lizards changed over time and the variations help them to survive.
3. The finches of the Galapagos islands are an example of evolution given in this exercise, but there is a good reason why the diverse and fascinating plant and animal biology of the Galapagos catalyzed Charles Darwin to begin establishing the Theory of Evolution. Another example of evolution is the Marine Iguanas of Galapagos islands.
The most astounding thing about the Marine Iguana is they are the only modern lizard to search for food in the sea.1 The Iguana genus are land dwelling except one variant: the marine iguana. They are the only species of iguana to live near the sea and they only exist in the Galapagos Islands. This is a very clear study of evolution. Some time 4.5 million years ago,2 the species diverged successfully from land iguanas to become marine lizards. In fact, their evolution worked so well that they are one of the oldest vertebrates on the island.2 The theory on how they to the island is the common ancestors of the marine and land iguanas possibly drifted out to sea on logs or other debris in a process called rafting.3 Through natural selection, speciation and hybridization, scientist theorize that these processes created the successful adaptation that is the marine iguana today.2