Self-study
The study of primates is interesting for many reasons, including the fact that only primates have opposable thumbs. ███ ██████ ███ █████ ████████ ███ ███ ████ ████████ ██████████ ██ ███████████ █ █████ ██████ ███ ███ █████ ██ ████████████ ███████ ████ ███████ ██ ██████ ███ ███ ████ ██████ █████ ████████ ████ ███ ██████████████ ███ ██████ █████████ ██████ ███ ████ ███ ██████ ████████ ███ ███████ ██ ████ ███████ ████ █ ██████ ███████ ███████ ██ █████ █████████
Summary
Only primates have opposable thumbs.
The only primates indigenous to Madagascar are lemurs.
Lemurs are lower primates.
Some lemurs are the only living diurnal lower primates.
All higher primates are thought to have evolved from a single diurnal species of lower primate.
Very Strongly Supported Conclusions
The only primates indigenous to Madagascar are lower primates.
All living diurnal lower primates are lemurs.
20.
Which one of the following ███ ██ ████████ ████████ ████ ███ ███████████ ██████
a
The chimpanzee, a ██████ ████████ ███████ ████ ███ ██████
Unsupported. All higher primates are thought to have evolved from a single diurnal species of lower primate. Some lemurs are the only living diurnal lower primates.
Chimpanzees might have evolved from a diurnal lower primate that’s now extinct.
b
No primates indigenous ██ ██████████ ███ ███████ ██████ █████████
Very strongly supported. As shown below, “lower primate” is a necessary condition of “indigenous Madagascar primate.” Taking the contrapositive tells us that if a primate is not a lower primate (i.e. if it’s a higher primate), then it is not indigenous to Madagascar.
c
No higher primate ██ ██████████
Unsupported. Just because all higher primates are thought to have evolved from a diurnal lower primate does not necessarily mean that all higher primates are diurnal. Some might have evolved to become nocturnal.
d
There are some ██████ ███████ █████████ ███████
Unsupported. If something has opposable thumbs, then it’s a primate. But being a primate isn’t sufficient to establish whether something has opposable thumbs. Lemurs are primates, but we don’t know whether they have opposable thumbs or not.
e
There are no █████████ ███████
Unsupported. We don’t know that all lemurs are diurnal. Some lemurs are the only living diurnal lower primates, but there might still be some lemurs that are nocturnal.