34.7
Contrast monotremes, marsupials, and eutherians in terms of how they bear young.
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 these factors in concept 25.4,pp. 565-570). For suggested answers, see Appendix A.
34.8
Mans are mammals that have a ge brain and bipedal locomotion
Ur tour of Earth’s biodiversity, we come at last to our own cles, homo sapiens,which is about 200,000 years old. En you consider that life has existed on Earth for at least billion years, we are clearly evolutionary newcomers.
Riced characters of humans 
My characters distinguish humans from other apes. Most ionusly, humans stand upright and are bipedal (walk on two). Humans have a much larger brain and are capable of lange, symbolic thought, artistic expression, and the manuface and use of complex tools. Humans also have reduced bones and jaw muscles, along with a shorter digestive tract. At the molecular level, the list of derived characters of huns is growing as scientists compare the grnomes of huns and chimpanzees. Although the two genomes are 99% ntical, a difference of 1% can translate into a large number changes in a genome that contains 3 billion base pairs. Thermore, changes in a smll number of genes can have e effects. This point was highlighted by recent by recent results wing that humans and chimpanzees differ in the expresn of 19 regulatory genes. These genes turn other genes on l off and hence may account for many differences been humans and chimpanzees.