Question

Count the number of new species that form in each group beginning at 60 mya (the first three species in each group were present around 64 mya, the first time period sampled, so we don’t know when those species first appear in the fossil record).

Short answer

The number of species with planktonic larvae at the beginning of 60 million years ago is three. The number of species with nonplanktonic larvae is also three at the beginning of 60 million years ago.

Step-by-step solution

Fossils

The organisms which lived in past geological age are sometimes preserved under the soil, and such remains or impressions of organisms are called fossils. The study of fossils helps to understand the process of evolution.

It also helps to understand the geographical conditions of the primitive earth and the reason for the mass extinction of some organisms.

Geographical time scale

The evolutionary theories propose various events of the primitive earth, and the geological time scale represents the calendar of the events of the primitive earth. The main divisions of the earth’s history are called eras. Periods and epochs are subdivisions of ears.

Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene are epochs of the geological time scale.

Identification of planktonic and nonplanktonic species in the given graph

The species with planktonic larvae are represented by pink bars. At the beginning of 60 million years ago, in the Paleocene epoch, three bars are present in this region. Therefore, the number of new planktonic larvae species formed at the beginning of 60 million years ago is three.

The species with nonplanktonic larvae are represented by blue bars. At the beginning 60 million years ago, in the Paleocene epoch, three bars were present. Therefore, the number of new nonplanktonic larvae species formed at the beginning of 60 million years ago is three.