Ch 9 review Flashcards
The oldest known fossils indicate life existed _____ years after Earth was formed
1 billion
The first life forms likely arose from the first molecules of life, organic molecules. Which molecule is an example of an organic molecule?
methane
-Organic molecules are the foundation of all life. All organic compounds contain carbon, but not all compounds containing carbon are organic. Methane, which does contain carbon, is considered to be an organic compound.
Which are the four stages in which life hypothetically began on Earth?
Small organic molecules –>proteins and nucleic acids –> ability to make copies –> membrane envelope
What process set the stage for genetic variation in eukaryotic populations and, as a result, natural selection?
evolution of sexual reproduction
brief episodes of great species loss
mass extinctions
molecules that contain the element carbon
organic molecules
blocks of geologic time scale separated by a major change in the forms of life
eras
geologic time spans that are shorter than eras
periods
environments that have escaped regional ecological change
refugia
group of primates that have relatively large brains
hominoids
This extinct primate had a body larger than a typical prosimian’s body and it had a tail but it was not like those of new world monkeys, which use their tails to hang from tree limbs. It walked through the jungle on all fours, and likely ate an omnivorous diet of leaves, plants, and insects.
To which clade does this monkey belong?
Old-world monkeys
-A primate species with a body larger than a prosimian would be considered to be an anthropoid. Not a new-world monkey because of its tail, the inability to walk upright like the bipedal hominoids would result in this extinct species belonging to the old-world monkey clade
A hominid lived between 40,000 and about 13,000 years ago. It has been nicknamed the hobbit because the skeletal remains, found on an island in Indonesia, suggest that adults were only about 1 metre tall. There is evidence that they lived alongside humans who arrived in the area about 45,000 years ago.
Which species is most likely described here?
Homo floresiensis
-The only hominids recognized from 45 000 years ago are Homo sapiens, Homo neanderthalensis, and Homo floresiensis. Homo sapiens represent modern humans, and Homo neanderthalensis, the Neandethals, were very similar in size to Homo sapiens, and even had a slightly larger skull. The species described in the question is most likely Homo floresiensis.
What is a genetically linked disease that, in heterozygous form, increases resistance to diseases cased by bacteria, such as cholera?
cystic fibrosis
A mass extinction of early chemoautotrophic prokaryotes occurred because of
a rise in atmospheric oxygen
molecules that contain the element carbon
organic molecules
