Instructions

A passage is given with five questions following it. Read the passage carefully and select the best answer to each question out of the given four
alternatives.
Passage:

There is exciting news for butterfly enthusiasts. By studying 207 species of butterflies, scientists have created an evolutionary tree painting the detailed picture of
butterfly relationships and evolution over time. An international team of lepidopterists carried out DNA studies and carbon dating analysis to understand the age and characteristics of butterflies. By comparing and merging previous studies on butterflies ,the researchers were able to create the new bigger and better evolutionary tree. “We still have a long way to go, but this is the first comprehensive map of butterfly evolution,” said Akito Y. Kawahara, associate professor at the Florida Museum of Natural History in a release. “Lots of previous studies cover butterfly evolution on smaller scales — by locality or taxon — but surprisingly few have reached across the breadth of butterfly diversity.” Dr. Kawahara is the corresponding author of the paper published in Current Biology. The report also supported previous studies that butterflies originated around 119 million years ago in the late Cretaceous period. After the mass extinction (65 million years ago), most of the butterflies diverged into many different groups. The butterfly species were placed in seven groups — Papilionidae, Hedylidae, Hesperiidae, Pieridae, Riodinidae, Lycaenidae and Nymphalidae. “Our analyses support swallowtails (Papilionidae) as sister to all other butterflies, followed by skippers (Hesperiidae) and the nocturnal butterflies (Hedylidae) as sister to the remainder,” says the report. The whites (Pieridae) were supported as sister to brush-footed butterflies (Nymphalidae), blues and metalmarks (Lycaenidae and Riodinidae). Previously, swallowtails and birdwings were believed to have a common ancestor but the new study showed that they feed on different plants. “That tells us that butterflies
and plants may have evolved together,” Dr.Kawahara added. They also studied the association of butterflies with ants. Some butterfly larvae secrete sugars that serve as a meal for ants and the ant in return protects the larva from other predators. This is a well-studied symbiotic relationship. The scientists report that most of the blue butterflies and hairstreaks and some of the metalmark butterflies exhibit this behaviour. “We [India] have about one fifth of the known moths and butterflies represented in Indian collections (3,800 out of an estimated 20,000 species). The only way they could undertake the study was the fact that they have
access to a good collection. We lack this in India,” explained Smetacek.

Question 120

When did the mass extinction of butterflies happen?


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