Lecture Notes: Review Session for Exam 1

These flashcards provide vocabulary and key concepts for Exam 1, covering biological anthropology, genetics, evolutionary forces, and hominin evolution.

Gene

A sequence of DNA bases that specifies the order of amino acids in a protein.

Regulatory Genes

Genes that act solely to control the expression of other genes.

Homeobox (Hox genes)

Highly conserved genes across animals that determine the body plan and control where and how fast structures grow during development.

Mitosis

A process of cell division resulting in two daughter cells, each containing $46$ single-stranded chromosomes.

Meiosis

A process of cell division involving a reduction division that results in four daughter cells, each containing $23$ single-stranded chromosomes.

Genetic Variation

Produced through sexual reproduction via mutation, random assortment, and recombination (crossing over).

Somatic Cells

All body cells that direct cell activity; they are diploid and contain $46$ chromosomes in humans.

Gametes

Reproductive cells (sperm in males, eggs in females) that transmit genetic information; they are haploid and contain $23$ chromosomes in humans.

Simple Traits (Mendelian traits)

Traits whose variations are controlled by different versions of a single gene.

Complex Traits

Traits that are influenced by more than one gene or environmental factor.

Sexual Dimorphism

The condition where males and females of a species exhibit differences in traits beyond just the gonads.

Sex

Observable physical characteristics that distinguish two kinds of human beings, females and males, needed for reproduction (Lavenda & Shultz 2015:375).

Gender

The social, cultural, and psychological constructions that are imposed on the biological differences of sex; recognized as a social construct.

Dominance

A trait that is expressed in the presence of a different allele.

Recessive

A trait that is not expressed in the presence of a dominant trait.

Homozygous

Having the same allele at the same locus on both chromosomes (e.g., $TT$ or $tt$).

Heterozygous

Having different alleles at the same locus (e.g., $Tt$).

Codominance

A condition, such as in the ABO blood group AB, where multiple alleles are expressed simultaneously.

Epigenetics

The study of chemical modifications to DNA associated with changes in gene expression without altering the genetic code itself.

Epigenetic Marks

Features found on a DNA molecule that regulate gene expression and are sensitive to environmental conditions, such as histone modification or methyl groups.

Transcription Factors

Protein products, such as those encoded by Hox genes, that influence which genes get transcribed.

Modern Synthesis of Evolution

The definition of evolution as a change in allele frequencies or gene frequencies of a population over time.

Natural Selection

An evolutionary force where biological variation, competition for resources, and environment determine which traits are inherited based on fitness.

Mutation

An evolutionary force that generates brand new genetic variation, typically found in non-coding regions of DNA.

Genetic Drift

An example of neutral evolution that reduces genetic variation, with the Founder Effect being a primary example.

Gene Flow

An example of neutral evolution involving the exchange of genes between two populations, which increases genetic variation.

Homologies

Similarities between organisms based on descent from a common ancestor, such as the limb structures of frogs and rabbits.

Analogies

Similarities between organisms based on common function with no assumed common evolutionary descent, such as grasping tails in different species.

Ancestral Traits

Traits inherited from a distant ancestor, such as body hair, mammary glands, and endothermy in primates.

Derived Traits

Newly evolved traits unique to a certain group, such as grasping hands, nails, and forward-facing eyes in primates.

Human-Chimp Last Common Ancestor

An ancestor that lived ~$6$ million years ago, was quadrupedal, had a chimp-sized brain, and foraged in trees.

Genus Australopithecus

Early hominins living between $1$ and $4$ mya characterized by small bodies ($64-100$ lbs), small brains ($340-500$ cc), and bipedal adaptations.

Homo habilis

A hominin appearing ~$2.4$ mya with a brain size of $630$ cc; possibly the first hominins to use stone tools.

Homo erectus

The first hominin group found outside of Africa (~$2$ mya), with a cranial capacity between $750-1250$ cc and utilizing Oldowan-style tools.

Anatomically Modern Humans

Humans that evolved in Africa between $300-200$ kya.

Encephalization Quotient (EQ)

A measure describing how the observed brain size compares to the expected brain size based on body mass.

Brain Metabolism Adaptations

Human strategies to manage high energy costs of the brain, including a high quality diet, reduced gut size, and altricial newborns with high body fat.