Natural selection human biology

Reproduction in past environments

Some Alleles In Human Populations That Cause Medical Problems Increased In Frequency Because They Also Increased -

Malaria

The Mutated Allele That Causes Sickle Cell Disease Increased In Frequency Over Generations Because It Also Increased

Resistance To -

Heterozygote advantage

The Frequency Of The Mutated Allele That Causes Cystic Fibrosis Increased In Frequency In Human Populations. Which Process That Occurs Over Generations Most Likely Caused This Increase?

Cholera, Tuberculosis, Or Typhoid Fever

In Some Environments, Heterozygotes With One Copy Of The Mutated Allele That Causes Cystic Fibrosis Reproduce Better Than Homozygotes. This Could Result From Heterozygotes Being More Resistant To -

Increases reproduction

An Allele That Causes Medical Problems Can Increase In Frequency In Future Generations

Of The Human Population If It Also -

1. Individuals Sneezing Or Coughing

2. Individuals Vomiting

3. Human Feces & Urine

Some Allele(s) That Affect Behavior Reduced

The Risk Of Infection In Our Ancestors

Because They Avoided -

1. Increased Creativity

2. Increased Innovation

3. Increased Problem-Solving Ability

How Could Alleles Relating To Dyslexia Have Improved Reproduction In Our Ancestors?

Virulence

The level of severity of symptoms you experience from different viruses (high virulence = horrible symptoms)

Increasing Transmission Of Less Virulent
Pathogens

We Could Favor The Evolution Of Less Virulent (Less Harmful) Individuals In A

Pathogen Population By -

Group natural selection

Animal population with individuals genetically programmed to cooperate produces more offspring than competing animal populations with individuals not genetically programmed to cooperate

Natural selection

The impact of all environmental factors on the frequency of alleles, and the traits they regulate, in a population over generations.

Yes, it increases the frequency of traits that improve reproduction in the current environment

Does natural selection increase reproductive ability over generations

• Alleles that increase reproduction

• Traits that improve reproduction

Alleles and traits that always increase

• alleles that reduce reproduction Traits

• Traits that reduce reproductive success

Alleles and traits that always decrease

In past environments environments, those alleles improved survival or reproduction, especially by protecting against disease (e.g., malaria), even if they cause illness today.

Why have some harmful medical alleles increased in humans

Heterozygote advantage

when individuals with one normal allele and one harmful allele have higher reproductive success than either homozygote.

• Sickle cell disease allele

• Beta-thalassemia allele

Which Alleles Increased Due to Heterozygote Advantage in Malaria Regions?

Heterozygotes (with sickle cell traits)

Which genotype is favored in regions with malaria

Homozygous (no sickle cell)

Which genotype is favored in regions without malaria

Yes, alleles that detoxify phytotoxins in plants and foods have increased allowing humans to safely eat more foods

Have alleles that detoxify food increased

Yes. Alleles that detoxify psychoactive compounds in fungi and plants have increased, some of which have therapeutic value.

Have Alleles That Detoxify Psychoactive Molecules Increased?

Over ~3,000 years, Tibetans evolved:

• Increased blood vessel diameter

• Increased capillary number

• Increased breathing rate

• Increased lung volume

• Reduced hemoglobin concentration

These changes improve oxygen delivery in low-oxygen environments.

How Did the Tibetan Population Adapt to High Altitude?