Natural Selection is the Process that Causes Evolution

Lower Oxygen (O2)

"One human population in Tibet has adaptations to higher altitudes that its related population living at lower elevations does not. This is an example of adaptations to _______________ ____." - fewer red blood cells - increased breathing rate - increased lung volume - increased blood flow to body's tissues

Required for a population to evolve by Natural Selection

- individuals must show genetic variation - some individuals must reproduce better than others due to genetic differences

Heterozygous Advantage

- resistant to Malaria - only mild sickle cell disease

Homozygous Dominant

- susceptible to Malaria - no sickle cell disease

Heterozygous

Many human populations live in areas with endemic Malaria. Which genotype is the most advantageous in these areas?

Homozygous Dominant

Many human populations live in areas without endemic Malaria. Which genotype is most advantageous in these areas?

Alcohol dehydrogenase gene

Many of our ancestors converted their crops into fermented foods that could be stored safely. Which gene enabled our ancestors to catabolize the ethanol molecules in these foods and eliminate their toxicity?

Multiple Amylase genes

Many of our ancestors cultivated starch-producing crops. Our ancestors that digested starch more efficiently consequently had more children because they possessed-

Multiple Amylase genes

Many of our ancestors cultivated starch-producing crops. Which mutation increased our ancestors' capacity to digest starch?

Ability to reproduce will increase

Natural selection has affected a population for 30 generations. How will natural selection affect individuals in this populations?

Better adapted to reproduce in current environment

Natural selection has affected a population for 30 generations. How will natural selection affect the individuals in this population?

Alleles that code for the enzymes that detoxify the psychoactive substances and other toxins in these substances

Our ancestors consumed a variety of hallucinogenic substances. In future generations of humans, this increased the frequency of-

Alleles that code for plant toxin inactivation

Our ancestors cultivated vegetable crops that contained plant toxins (phytotoxins). Which alleles enabled our ancestors to consume these vegetables safely?

Lactase gene expressed in adulthood

Some of our ancestors had access to dairy products as adults because they domesticated milk-producing mammals. Which mutated allele enabled these adults to digest the lactose in dairy products?

The alleles that reduce the ability to reproduce

Which alleles in a population will always decrease in frequency in the future generations of the population?

The alleles that increase the ability to reproduce

Which alleles in a population will always increase in frequency in future generations of the population?

Biotic and Abiotic factors

Which factors in the habitat could affect the ability of individuals to reproduce under current environmental conditions?

Heterozygote Advantage

Which mechanism accounts for the relatively high frequency of the Sickle Cell Disease Allele in human populations inhabiting regions where Malaria is endemic?

The traits that increase the ability to reproduce

Which traits in a population will always increase in frequency in future generations of the population?

Homozygous Recessive

- resistant to Malaria - has fatal sickle cell disease

Genetically-identical

A population of Aphids (insects) cannot evolve over generations by natural selection if all the individuals in the population are-

Amylase

Enzyme that digests starch to produce glucose