Tracing The History Of The Tortoise IELTS Reading Test

The IELTS reading section makes for a primary part of the exam. It’s important to take as many reading sample tests as possible to prepare for the same. We’ve curated one under the topic of tracing the history of sea creatures, with solutions and detailed explanations, to help you attain the necessary practice for your big day!

Tracing the History of Sea Creatures

If we trace the origin of different animal groups, we can conclude that every animal once resided in the ocean. The history of evolution suggests that, at many points, various species of animals moved to live on land. Living in the sea made them carry the seawater in them wherever they went. This made them inhabit some of the driest parts of the land, including deserts. While plenty of evidence suggests that insects, mammals, birds, and reptiles have moved from the sea to the land, other animal groups followed in their footsteps. This includes snails, scorpions, crustaceans like land craps, woodlice, centipedes and millipedes, and many other worms and spiders. 

While the animals moved out of the sea, let's not forget the role of the plants in supporting the different animal groups on the land. Plants are the ecological basis upon which wildlife depends. More than 450 million years ago, plants took the evolutionary step of shifting from water to coast side or land. 

The progress from sea to land came with its own set of challenges, and the animals faced difficulties in two important process; reproduction and breathing. This process resulted in many animals returning to their initial habitat, the sea, and a few animals, what we call intermediaries, adjusted to living both on and water. 

The animals returned to the sea include whales, dolphins, dugongs, and manatees. Although they returned to their ancestors' marine habits and ceased exhibiting all characteristics of land creatures, they breathed air. Since these marine creatures never developed gills and cannot breathe underwater, they breathe air through the nostrils. Seals, on the other hand, only partially returned to their ancestors' living habits. Their characteristics exhibit what intermediaries would show if the whales or dugongs did not retrace their steps to the sea.

Turtles, another sea returnee, exhibit a striking feature different from other animal groups that made it back to the sea. All turtles plonked their eggs on the land. Sea turtle visit beaches, dig holes, lay eggs, and depart back to live in the water. Besides this, similar to the whales, they breathe through their nostrils.

Even if fossils are found in bad shape and only a few fragments, they carry a lot of helpful information and can be used to determine if the animal lived on land or sea. Two significant fossils from early dinosaur times, namely Palaeochersis talampayensis and Proganochelys quenstedti, reveal a lot of useful information that helps track the lineage of all modern tortoises and turtles. These fossils suggest that all modern turtles descended from a terrestrial ancestor that inhabited the earth before most of the dinosaurs. Ichthyosaurs, extinct marine reptiles, lived alongside the dinosaurs. They had fins and sleek body structure. The fossils resemble the dolphins, and it can be confirmed that they lived like them in the midst of the water. Identifying the fossils of turtles may not reveal everything at first glance. Researchers measure the forelimb bones to understand their characteristics.

Jacques Gauthier and Walter Joyce of Yale University took three different bone measurements in 71 different species of tortoises and living turtles. They plotted three different measurements against each other on a trianglular graph paper. The different tortoise species were clustered separately, the water turtles in the lower section of the graph and the land turtles in the upper part. In comparison, these tortoises showed distinct features, the amphibious species that live both aquatic and terrestrial life overlapped in the graph. They appeared midway between the terrestial tortoises and the aquatic turtles.

As soon as this step is complete, and it is determined whether the tortoises belonged to sea or land, the following process was to identify the location of the fossils. The bones of JR talampayensis and P quenstedti were fossils of the land tortoises. They stray from the era when turtles did not migrate back to the sea and ocean. They were identified in the graph with the tortoises of the dry land. 

Individuals commonly conclude that land tortoises of today have stayed back on land since the earliest times. A few mammals returned to the water, while the others stayed back. But the ancestry of all the modern tortoises and turtles points otherwise. The family tree points out that nearly all branches of tortoises are aquatic. The land tortoises of today come from one branch, existing alongside branches comprising of sea turtles. It suggests the ancestors of today's turtles and tortoises returned into the sea and became aquatic turtles, only to return to the land as tortoises of late.

Tortoises represent the most significant double return among all the creatures that migrated to land and then back to the water. Their distant predecessors, like all birds, reptiles and mammals, were aquatic fish and, prior to that, different worm-like animals stretching back to the primeval bacteria, still inside the sea. Later, ancestors became terrestial and remained there for several ages. Eventually they returned to water and turned into sea turtles. But in the end, they returned back to the earth as tortoises, many of which presently dwell in the parched land.

Questions 1-4

Answer the questions below.

Choose NO MORE THAN THREE WORDS from the passage for each answer.

1. What had to transfer from sea to land before any animals could migrate? 
2. Which TWO processes are mentioned as those in which animals had to make big changes as they moved onto land? 
3. Which physical feature possessed by their ancestors, do whales lack?
4. Which animals might ichthyosaurs have resembled?

Questions 5-7

Do the following statements agree with the information given in Reading Passage?

In boxes 5-7 on your answer sheet, write

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this

1. Turtles were among the first group of animals to migrate back to the sea.
2. It is always difficult to determine where an animal lived when its fossilised remains are incomplete.
3. The habitat of ichthyosaurs can be determined by the appearance of their fossilised remains.

Questions 8-13

Complete the flowchart below.

Choose NO MORE THAN TWO WORDS AND/OR A NUMBER from the passage for each answer.

Write your answers in boxes 8-13 on your answer sheet.

Method of determining where the ancestors of turtles and tortoises come from

Step 1

71 species of living turtles and tortoises were examined and a total of 8__ were taken from the bones of their forelimbs.

Step 2

The data was recorded on a 9 __ (necessary for comparing the information).

Outcome: Land tortoises were represented by a dense 10 __ of points towards the top.

Sea turtles were grouped together in the bottom part.

Step 3

The same data was collected from some living 11 __ species and added to the other results.

Outcome: The points for these species turned out to be positioned about 12 __ up the triangle between the land tortoises and the sea turtles.

Step 4

Bones of P quenstedti and P. talampayensis were examined in a similar way and the results added.

Outcome: The position of the points indicated that both these ancient creatures were 13 __

Questions 14

Choose the correct letter, A, B, C or D.

Write the correct letter in box 14 on your answer sheet.

According to the writer, the most significant thing about tortoises is that

1. They are able to adapt to life in extremely dry environments.
2. Their original life form was a kind of primeval bacteria.
3. They have so much in common with sea turtles.
4. They have made the transition from sea to land more than once.