Question

MAKE CONNECTIONS Develop a hypothesis to explain why the diversity of mammals increased in the Cenozoic. Your explanation should consider mammalian adaptations as well as factors such as mass extinctions and continental drift (review Concept 25.4).

Short answer

Several mammalian adaptations enabled them to adapt to the changing atmosphere. Some of the adaptations in mammals include are endothermic, produce milk to nourish their young ones, they have well-developed teeth, and possess large brains.

All these adaptations increased after the Cretaceous period of mass extinction and continental drift leading to the extinction of mammals and also divergence and variations between different mammalian groups.

Step-by-step solution

Mass extinctions and continental drift

Mass extinctions are events in biological history that led to wiping out several organisms once found on Earth. This also led to an increase in divergence and also caused variations. Continental drift is a biological process through which continents are separated from one another due to external factors.

Cenozoic period

The diversity of organisms increased after the Cenozoic period because several events like mass extinctions and continental drifts took place. Due to this, several organisms like dinosaurs became extinct.

Diversity in mammals and their adaptation after the Cenozoic period

The diversity in mammals increased after the Cenozoic period due to the adaptations that mammals underwent to survive in a habitat successfully. Some adaptations that mammals underwent include maintaining body temperature even in different climatic conditions and having a large brain for cognition.

They also produce milk to feed their young ones. All these adaptations caused variations between mammals and hence led to an increase in diversity.