Anthropology 15: The Human Life Cycle and Introduction to the Theory of Evolution

Vocabulary flashcards covering cellular organization, the human reproductive cycle, gametogenesis, chromosomal genetics, DNA structure, and fundamental evolutionary concepts from Anthropology 15.

Morphology

The physical form, structure, or visual appearance of a cell, tissue, or organism.

Physiology

The biological and mechanical functions carried out by a cell, tissue, organ, or organ system.

Tissue

An organized group of similar cells working together to carry out a specific physiological function.

Organ

A self-contained structure composed of multiple tissues joined together to execute specific complex functions (such as the liver or heart).

Organ System

A group of organs collaborating to execute integrated bodily functions, such as the digestive or circulatory systems.

Liver Parenchyma (PA)

The functional cellular tissue of the liver, consisting predominantly of hepatocytes.

Hepatic Portal Triad

A distinctive microstructural arrangement in the liver consisting of portal vein branches ($\text{PV}$, endothelial cells), hepatic arteries ($\text{HA}$, muscle, connective tissue, and endothelial cells), and bile ducts ($\text{BD}$, epithelial cells).

Spermatogenesis

The production and development of male gametes (spermatozoa), which takes place inside the seminiferous tubules of the testes.

Seminiferous Tubules

Tightly coiled tubular structures within the testes where sperm cells are generated and mature.

Oogenesis

The process of egg (ovum) production and maturation, which takes place in the ovaries.

Primary Oocytes

Immature female germ cells produced during the fetal period; approximately $2 \times 10^6\text{--}4 \times 10^6$ are present at birth, of which only about $400$ are ovulated across a woman's lifetime.

Spermatogonia

Diploid male germ cells ($46$ chromosomes, $2$ chromatids per chromosome) that divide by mitosis to produce primary spermatocytes.

Primary Spermatocyte

A diploid male germ cell ($46$ chromosomes, $2$ chromatids per chromosome) that undergoes the first meiotic division.

Secondary Spermatocyte

A male germ cell containing $23$ chromosomes ($2$ chromatids per chromosome) produced following the completion of the first meiotic division.

Spermatid

An immature, haploid male germ cell ($23$ chromosomes, $1$ chromatid per chromosome) resulting from the second meiotic division.

Spermatozoon

The fully differentiated, mature male haploid gamete ($23$ chromosomes, $1$ chromatid per chromosome).

Oogonia

Diploid female precursor germ cells that multiply via mitosis during fetal life and differentiate into primary oocytes.

Secondary Oocyte

A haploid female germ cell formed when a primary oocyte completes its first meiotic division prior to ovulation, along with the first polar body.

Polar Body

A small haploid byproduct cell formed during oocyte meiosis (first and second polar bodies) that receives almost no cytoplasm and does not develop into an ovum.

Ovum

The mature female gamete produced after the secondary oocyte completes its second meiotic division following fertilization.

Zygote

The diploid cell resulting from the fertilization of an ovum by a spermatozoon, containing $23$ pairs of chromosomes ($46$ chromosomes total, half maternal and half paternal).

Diploid ($2N$)

Possessing two complete homologous sets of chromosomes ($46$ chromosomes in humans); the cellular state of human bodies throughout most of the life cycle.

Haploid ($N$)

Possessing a single set of unpaired chromosomes ($23$ chromosomes in humans), typical of mature gametes.

Mitosis

The cellular division of a diploid (or haploid) cell that yields $2$ genetically identical cells possessing the identical ploidy level as the parent cell.

Meiosis

The two-step reductional cell division process by which a single diploid cell produces $4$ haploid gametes.

Histones

Basic proteins that spool and package the DNA double helix into structural units called nucleosomes.

DNA (Deoxyribonucleic Acid)

The hereditary macromolecule containing $3.1 \times 10^9$ nucleotide pairs per haploid set ($6.2 \times 10^9$ per diploid cell) composed of four chemical bases ($\text{A}$, $\text{C}$, $\text{G}$, $\text{T}$).

Protein-Coding Gene

A specific sequence of DNA nucleotides that holds the instructions to synthesize a particular functional protein.

Phenotype

The composite of an individual's observable traits and characteristics, determined through interactions between DNA and environmental factors.

Environment (Phenotypic)

The aggregate of non-genetic influences shaping phenotypic expression, encompassing family, culture, diet, climate, and exposure to pathogens or toxins.

Regression Towards Mediocrity

The statistical phenomenon described by Francis Galton (1886) where offspring of parents with extreme traits tend to regress toward the population average.

Germline Mutation Rate

The baseline frequency of nucleotide substitutions per generation, estimated at $1.1 \times 10^{-8}\text{--}1.7 \times 10^{-8}$ per site, corresponding to roughly $30\text{--}50$ novel mutations per individual genome.

Biological Fitness

The relative likelihood of an organism surviving to reproductive maturity and the quantity of surviving offspring it produces, governing the trajectory of allele frequencies over time.