Evolutionary Anthropology: Microevolution & Macroevolution: Lecture Four

Flashcards covering microevolution, skin tone evolution, race biology, and macroevolution based on lecture notes.

What are the main topics covered in this lecture?

Microevolution, evolution of skin tone, biology of races and racism, and macroevolution

What are the functions of skin?

Protection of tissues, thermal regulation, excretion, sensation, storage, vitamin D synthesis, and protection from UV

What are the three layers of skin?

Hypodermis, dermis, and epidermis

What cells produce melanin?

Melanocytes

How does skin tone vary phenotypically?

Melanin production, environmental factors like tanning, dispersion from basal cells, thickness of skin, blood vessels, and carotene pigment.

What gene is highly polymorphic and associated with skin tone, even in Neanderthals?

MC1R gene

What is Gloger's rule?

Greater pigmentation at lower latitudes.

What are the disadvantages of UV rays?

Sunburn, disruption of skin barrier, cancer, and chemical and vitamin breakdown.

What vitamin's production is stimulated by UV rays?

Vitamin D

What are the functions of Vitamin D?

Skeletal growth, calcium transportation, and kidney function

What conditions can result from insufficient Vitamin D?

Rickets and Osteomalacia

Besides vitamin D, what other factor is impacted by UV radiation related to skin tone?

Folate degradation

Why is folate important?

Reproductive outcomes, neural development, DNA synthesis and repair, sperm

What is the evolutionary explanation for dark skin pigmentation?

Protection from intense UV radiation.

What is the evolutionary explanation for lighter skin pigmentation?

Higher vitamin D production in areas with less UV radiation.

Where do almost all skin tones exist?

Africa

What are some of the problems with racial categories?

Socially constructed, highly variable, do not account for variation, focus on only a few features

Where does more genetic variation exist, according to lecture notes?

Africa

What percentage of genetic variation is found within local groups versus between groups?

93-95% within local groups, 3-5% between groups

What is the 'Out-of-Africa' model related to genetic variability?

Greatest genetic variability within Africa, decreasing with distance from Africa

According to the lecture, what is the impact of understanding human variation?

Caution not to overinterpret superficial traits, consider biological and cultural interactions

What is a problem to consider with commercial ancestry tests?

Problematic promotion and interpretations

Define populations, according to Shook et al (2019)

A local interbreeding group with reduced gene flow between themselves and other groups of humans

What are the two scales of evolution?

Microevolution and Macroevolution

How is macroevolution defined?

Evolution at levels higher than the population

What connects micro-to macroevolution?

Speciation

What is the Biological Species Concept (BSC)?

Species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups

What are some limitations of the Biological Species Concept?

Cannot be applied to asexual organisms, organisms with unknown interbreeding, fossils, or intermediate states between species

What is the Phylogenetic Species Concept?

Groups of organisms that share a unique, shared evolutionary history and can be distinguished by a unique combination of character states

What are the two patterns of speciation?

Anagenesis and Cladogenesis

What is adaptive radiation?

Formation of many new species following the availability of new environments or the development of new adaptations

What two factors need to be in place for speciation to occur?

Reduction or elimination of gene flow and genetic divergence

What is Allopatric Speciation?

Speciation that occurs with geographic isolation