Ancient Reproductive Theories (384-322 BCE) PDF

WEEK 2 & CHAPTER 1: **Prehistoric artifacts:** female bodies with reproductive features **Aristotle: Epigenesis** - Theory that development begins with the male seed providing form and the female body providing material nourishment, with the fetus gradually forming from unorganized matt...

WEEK 2 & CHAPTER 1: **Prehistoric artifacts:** female bodies with reproductive features **Aristotle: Epigenesis** - Theory that development begins with the male seed providing form and the female body providing material nourishment, with the fetus gradually forming from unorganized matter rather than being preformed. - Male seed provides form, while female body provides nourishment **Epigenetics:** Epigenetics focuses on how cells differentiate and develop, building on Aristotle\'s concept of epigenesis but incorporating equal genetic contributions from both parents to explain gene expression and cellular development. **Microscope:** revealed sperm, led to debates about its function **Preformationist theory**: the belief that the developing human being is already fully formed and encased within the sperm or the egg, with growth involving only an increase in size rather than complexity. It also suggested that all future generations were pre-encased within the original seed, aligning with the idea of divine or predestined creation. **Cell theory:** cells are the structural and functional units of all living organisms, capable of regenerating through division. This theory, developed in the 19th century, replaced preformationism by showing that reproduction occurs at a microscopic level through egg and sperm cells. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Textbook: REPRODUCTIVE THEORIES: THEN & NOW - Reproductive understanding has evolved: - Early humans [did not] connect sexual activity with reproduction - 20^th^ century: - Major advancements like decoding the human genome, biochemical contraception, and conception outside the body - Progress is not linear, it is influenced by historical questioning and dominant ideologies PREHISTORIC VENERATION OF A FEMININE DIVINE: - Prehistoric artifacts and imagery: - They often depict female bodies with exaggerated reproductive features - Breasts - Vulvas - Swollen bellies - Interpreted by archaeologists (Marija Gimbutas) as representations of life cycles and fertility - Example: - **Venus of Willendorf** (30000-25000 BCE) emphasizes feminine reproduction - Symbolism: - Animals associated with reproduction - Example: - Bull for the uterus - Prehistoric reproduction theories often centered on females bodies, excluding the role of heterosexual copulation (sex) - Critiques: - Scholars like Richard Lesure caution against overgeneralizing these figurines meanings - Male figures rarely appear -- raises questions about gendered representations in prehistoric reproduction imagery ANCIENT PHILOSOPHIES OF GENERATION: EPIGENESIS - **Aristotle's Theory (384-322 BCE)** - **Introduced epigenesis:** - Development starts with the male seed, which provides form, while the female body provides nourishment - Male semen described as the "[principle of soul]," elevating the male role spiritually - Menstrual blood, seen as inferior but essential, was the material upon which the seed acted - Competing theories: - **Hippocrates** believed in the combination of male and female semen to form the fetus - **Galen** initially supported this but later adopted Aristotle's theory, reinforcing female passivity - Religious influence: - Thinkers like Saint Thomas Aquinas integrated theological beliefs into reproduction, positioning male sperm as a divine intermediary - Anatomical misunderstandings: - Female anatomy was depicted as an inferior version of male anatomy - Ovaries -- cooler than male testes - These misconceptions shaped societal views on gender and reproduction THE SCIENTIFIC REVOLUTION & PREFORMATIONISM - New discoveries: - Microscope revealed sperm but led to debates about its function - Ovists believed the egg contained a preformed being, while spermists emphasized the role of the sperm - Transition to genetics: - By the 19^th^ century, **cell theory replaced preformationist** - Cells were recognized as the structural and functional units of life, regenerating through division - Religious and scientific interplay: - Theories of creating intertwined with religious beliefs, particularly the idea of a divine male creator [ ] MODERN REPRODUCTIVE SCIENCE: GENETIC RECOMBINATION - Milestones in genetics: - DNA discovered as the molecule of inheritance (1869), with its structure discovered in 1953 - Chromosomes identifies as units of heredity, with detailed mapping by the early 20^th^ century - **Barbara McClintock** demonstrated genetic recombination through "crossing over" - Understanding of genes: - **Gregor Mendel's** work on inheritance patterns in peas laid the groundwork for modern genetics - Traits were shown to be passed through dominant and recessive genes - **Epigenetics**: - Contemporary theories focus on the differentiation of cells, building on Aristotle's concept of epigenesis but integrating equal genetic contributions from both parents ASSISTED REPRODUCTION & GENETIC REPLICATION: - **IVF and related tech:** - **Robert Edwards and Patrick Steptoe** achieved the first successful human IVF in the 1970s - Techniques include hormonal stimulation, gamete freezing, embryo transfer - Animal research contributions: - Early experiments with animal embryos (rabbits, cows) refined IVF techniques - Embryo freezing and genetic manipulation initially developed for agricultural applications - Genetic screening: - Allows for the identification and correction of genetic abnormalities in embryos before implantation CONCLUSIONS: - Shifting perspectives: - Reproductive theories have evolved from female-centric to male-dominant and finally to balanced genetic contributions - Male roles were historically overemphasized due to cultural and religious beliefs - Modern understanding: - Reproduction is now seen as an equitable genetic exchange, informed by cellular and genetic insights - Historical influences still permeate societal perceptions of reproduction and gender roles Lecture **Early Theories of Reproduction:** - It is almost impossible to discern any theory of reproduction from what we have recovered from prehistoric times. - Images and figures depict human reproduction on the female body as pregnant, birthing and nursing. - Relationship between heterosexual coitus and pregnancy was not fully understood yet - Patterns of how we understand reproduction change over time - Shift from a female venerated relationship to reproduction **I - Prehistoric Generation: Figurines** - Land related to reproduction in the human - Historic figurines that represent reproduction -- 95% of figurines were female - Period where reproductivity was associated with the cis female body - Totem poles/ the spirit - Believed to be the thing that impregnates a women - Belief systems that children were born from a female body but spirits may have generated the child - Like a moon or bear A stone statue of a person Description automatically generated - *Venus of Willendorf* - \'Seeds\' on the head represent the circle of life - Made of limestone - Large boobs and butt - Found in lower Austria, 30000 -- 25000 BCE - Had what looks like vulva, uteri, breasts - Seen as a fetish [Adopting the sign of Venus]  - From \~ 2400 to 250 BCE, Venus goddess was gradually replaced by masculine divinities." it was seen as a fetish - The symbol was taken back by women's rights activists in the 1960s. **II - Ancient Theories of Generation: Heat = Perfection** - [Heat = perfection ] - Provides nourishment and life - Referring to food and plants - Reproduction linked to production of food and land - Celestial clock - Remedies from herbs, healing agents that are concocted from heat - Heat was used to create weapons/jewelry - which signified social order - Heat was used to cauterize and heal wounds - Heat seen as purifying - it is a distiller - To purify the body into it should like essence - Male seed (perfected from semen); - Because they produced more heat, they are more purified - The male as able to perfect its semen, and to generate humans within the static and materialistic female assumes not only a superior role, but one associated with godliness. - [Women produce less heat than men] - Women\'s semen was not pure - Hence, they are smaller, dumber, weaker, live less - Cold = crude, not an essential agent - Female (unperfected) semen (menses) - Galen: Women's reproductivity is not as developed as that of men's, and suffers from a "natural deficiency" - Accused Aristotle of describing the difference between male superiority and female inferiority in reproductivity, Galen (130 -- 210 AD) explored why it is that women cannot purify their semen and remain the colder of the creatures: "A natural deficiency." - Galen defines this deficiency as a failure in women to generate heat to purify the menses - Aristotle 384-322 BCE - His approach relies on the idea that heat perfects. We have long understood that the sun makes things grow; fire helps prepare our food and has the power to form metals into useful tools and venerated figures. - Aristotle didn't create the theory of heat but uses it to explain human reproduction: claiming that like men women also emit semen (dark-colored menstrual fluid), but it is unperfected by heat, unlike the lightly colored and perfected male semen. It is also considered one of the first, proto-scientific attempts at explaining human reproduction. **The Mechanism of Lack of Heat:** - How vessels feed the right and left ovaries (called testes by Galen) explains the natural deficiency of females: - Galen proposes is that one testis (ovaries) is fed cleansed or purified fluid, while the other is not. Females, it is concocted, emanate from the left testis, and males from the right ensuring a "natural deficiency" in female physiology. - One ovary is fed cleansed or purified blood from the kidney and produces males. The other is not, and produces females **The Power of Imagination and Concoction: Female Reproductive Fluids** - Women's reproductive fluids inferior to that of men or obscured: (Always comparing body parts) - Women's abundant and impotent "semen" is unpurified (bloody) vs the precious and more rare and white semen of men that acts as the seed of being ("the principle of soul"; the matrix) - Assumes ejaculation (the production of fluid upon sexual excitement as touch) only occurs in men - That women do not emit pale/clear fluids when sexually excited (Aristotle does not recognize the clitoris nor female orgasm) - Women cannot purify - That menses is the same as semen, only unpurified - Aristotle's theory that the male purified semen gave form to the unpurified but necessary matter from women (menses) persisted over 1200 years **Seed Theory:** - Aristotle\'s theory is seen as epigenetic - Seed theory claims only one is responsible for the being - Male semen contains the ability to generate the fetus in the female (the human is not performed in the male semen, but acts like a seed in the right growing conditions) - The female can only form within itself (like soil) - Did not believe that there was a recipe in the male semen that acted upon to female - All is contained in the origin and the origin extends to other things - Can be compared to the Judaic Christian belief in creation: from God comes the power of creation/formation imparted to the unformed material of the world \> mundus \> mundane - Believes that the origin of all is God - God creates man, man creates women - The female, like nonhumans, is associated with the matter of the world: mundane (of the world), "a nurse to the seed," and not a parent. **Early Dualism:** - Earth is associated with an underworld, foundations of life - Males are associated with the underworld - Females are the mundane aspect of creation - Early reproductive theories, that now understood the connection between coitus and birth, reflect this binary in gender-based reproductive dualism: - Men associated with the illumination, formation and perfection, and women with darkness, material necessity and mystery. **The Devine Creator vs Woman - the Earth-Bound Nurse:** - Wet nursing - Women hired someone to nurse their children - The women would have just had a baby for them to nurse another child - Mother can change their milk according to what the baby needs **Wrong and Right:** - Getting it anatomically wrong in 1500s and right in the late 1700s - For 1500 years it was believed that male reproduction was superior to female **III - Early Modern Reproductive Theories** - Late 1600s - rejection of human generation as progression from the simple and unorganized to the complex and organized; and a rejection of the mechanization of growth. - This is epigenesis, Aristotle's argument - It is replaced by [Preformation Theory] and the idea that growth is the unfolding from [pre-existing structure: growth is in size not in complexity] - By the late 1700s preformation theory is replaced by [epigenesis: ] - The embryo gradually develops from unorganized matter; embraced by Darwin who believed man's greater size meant a greater role in reproduction than the female. **Preformation Theories:** - According to preformation theorists, the developing human being is encased in its entirety in either the sperm or the egg. All generation is explained as "programmed encasement" and was considered God-given or predestined to be. - All beings follow a line of destiny - Encasement: - Russian dolls, same thing replicated - Preformation claims that each seed contains all the seeds of subsequent generations. This is also known as encasement and assumes a single parent to the entire human race. This resonates with the idea behind the Hand of God. **The Homunculus:** - Microscope - 1500s - Visualization becomes very important - Looking into physiological differences between beings - Bumps on ovaries - Find eggs - Antonie van Leeuwenhoek examined his semen through a microscope, in 1679, he saw millions of "little animalcules" swimming, which he named sperm animals or spermatozoa. - Animalculism claims that the fully formed human is encased in the sperm's head or the homonculous, waiting for the correct conditions to unfold and grow; an example of encasement and preformation. **Ovism:** William Harvey (1651): \"ex ovo omne vivum\" (every living thing comes from an egg) 1651 Renier de Graaf (1672): proves the presence of eggs by comparing the number of rabbit ovarian follicles before coitus to the number of spheres (fertilized eggs) found in the Fallopian tubes afterwards. 1672 1669 Jan Swammerdam (1669): \"All animals come from an egg laid by a female of the same species.\" **Chicken Eggs:**  - Chicken eggs a common way of examining reproduction. In the apparent absence of human eggs, it was assumed that women were simply carriers of the material required to develop male seeds implanted during coitus; like an egg. **Epigenesis:** Karl von Baer identifies the human egg 1827 1839 Darwin\'s theory of evolution: organisms arise and develop through the natural selection of small, advantageous inheritable traits. 1859 Cell theory: germ or sex cells (egg and sperm) of a certain kind would produce adult organisms of the same kind. 1942 Human reproduction is as we understand it now : the egg and sperm, as genetic equals, contribute to the formation of a combined but distinct third being. **Cell Theory: *part of new reporudctive technologies*** - Discover cells and function - Electricity in the body - How blood circulates - Discover hormones - in the form of fluid - 1665 Robert Hook sees cells under the microscope and names them as such because they look like monk's sleeping cells - 1839 Schleiden and Schwann argue that cells regenerate through division and are the basis of all organisms, including egg and sperm cells reproduction now happens at a very small scale, and everywhere in the body **The Gene:** - Understanding of genetic traits without seeing a DNA spiral - Changing theories of reproduction - 1866 Downs syndrome is is described as an inherited disease - At the same time Gregor Mendel identifies inherited traits in plants - 1859 George Darwin argues how genetic traits evolve to the benefit of the species - 1889 Hugo de Vries: "inheritance of specific traits in organisms comes in particles \[called\] (pan)genes" - With the advent of cell theory early modern scientists were able to marry what they knew about inheritance from centuries of livestock practices, agriculture, and medicine to now-visible structures and functions at the mircroscopic level. It resulted in the identification of the chromosome and the gene in the late 19^th^ century **20th Century - Genesis is Genetic:** - Early on in the 20^th^ century chromosomes were seen to be hereditary units and necessary for embryonic development - 1913 a genetic map of the chromosome is made, awnd sex-linked inheritance is discovered - 1930-1950 distinct contributions are identified for the cell nucleus where DNA is discovered and found responsible for cellular reproduction - 1952 the double helix structure of DNA components, G-A-C-T, is identified - 1955 each human is found to carry 46 unique chromosomes -- the distribution of chromosomes to offspring is clarified (23 from each parent). - Females and males have genes and they look the same - Moving away from a long period of discrimination that favoured males **Heroic Age of Endocrine Discovery: 1929-1935** - Discovery of hormonal secretions that ripen and release the human egg and prepare the uterus for implantation - Sex hormones are discovered to be bisexual: women and men produce estrogen and testosterone - Sex hormones are linked to external sex traits and are used to "balance" sexual orientations **Menstruation:** - "A chaotic disintegration of form" - "Failed reproduction" - Menstruation and menopause tend to be depicted in terms of chaos, failure and loss. **The Egg:** - Described as: - Large and passive - Nothing about their equal genetic contribution - Silence about the egg's power to allow sperm into the egg