Chapter 7 Flashcards
lactose
a disaccharide found in dairy products too large to pass through the cells that line the large intestine.
what is lactase and how does it work?
it is the enzyme that breaks down lactose into its monosaccharide components, glucose and galactose, which are small enough to be transported across cell membranes of the digestive tract into the circulatory system, where they are carried to cells to be used for energy processes and raw building materials.
what happens when someone ingests lactose but doesn’t produce lactase?
The naturally occurring bacteria in the gut break down the lactose which produces a variety of molecules – hydrogen, C02, and methane – which leads to a variety of symptoms – gas, bloating, nausea, and diarrhea.
Did humans always usually produce lactose into adulthood? Why or why not?
The majority of human history has consisted of a dependence of milk that disappearance past infancy due to hunter-gatherer diets of primarily meat and wild plants. Past infancy, the lactase enzyme did not need to be produced.
How does natural selection play into the development of large populations developing the lactase enzyme into adulthood?
Prehistoric people that began farming may have also started raising animals for the consumption of their milk and cheese. In colder northern European climates, consuming dairy might have been essential to survival.
what enzyme causes milk to coagulate into curds and then cheese?
rennin
about how much of the world’s population is lactose intolerant?
65-70%
What is the word for people who can digest lactose?
Lactase persistent
What is the rate of lactose intolerance in places where dairy consumption is scant?
up to 95% in places like southern Africa and much of Asia
What is the rate of lactase persistence in places like northern Europe and Scandinavia?
95%. People have consumed dairy here for thousands of years.
Why do lactase supplements need to be taken with the dairy food?
The lactase enzyme needs to come in contact with the lactose in order to break it down.
What is required to make cheese?
Rennin, which is derived from rennet, which comes from the last chamber of a cow’s stomach.
What is the theory standing about how cheese was invented?
Someone left milk standing in a bag made from a cow’s stomach for too long until it curdled.
Individuals evolve, not populations. (T or F)
False. Populations, not individuals, evolve. Natural selection does act on individuals but pops. show the evolution.
Only heritable, genetically coded traits are subject to natural selection. (T or F)
True.
How does the fossil record provide evidence of evolution?
Contains transitional forms of species, like whales with rear legs, and reveals an ordered appearance of life on Earth, with the oldest prokaryotes at the bottom.
biogeography
the study of the geographic distribution of species.
comparative anatomy
Comparisons of the body structures of modern organisms.
Bioinformatics
Bioinformatics employs computational tools to process genetic data.
the units of evolution
populations
qualifications of a population
- can meet and mate
gene pool
a gene pool consists of all versions of all the genes carried by all the individuals in a population.
how does genetic variation in a gene pool arise?
Through genetic mutations.
how does natural selection act on a gene pool?
Traits that enhance survival and reproduction will be represented with increasing frequency in the gene pool.
*gene flow
genetic exchange among populations due to migration
founder effect
when a few individuals migrate to a new, isolated habitat.
bottleneck
when a population is drastically reduced
*genetic drift
a change in a gene pool by chance, like through death or emigration
sexual selection
Sexual selection is a form of natural selection that depends on an individual’s ability to obtain a mate
speciation
the evolutionary formation of new species
