Week 9-Gender and Sexual Behaviour Flashcards
Why is sex important?
Sexual reproduction:
- Reduces the chance of passing on mutations
- Gives diversity (to adapt to a changing environment)
- “survival of the fittest”
Without offspring, no species can survive.
Which species produces in an asexual way?
What is asexual reproduction?
Asexual: amoeba
When a species makes more of itself without exchanging genes through sex.
What is DNA?
Is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA). Mitochondrial DNA are passed from mother to offspring.
What are genes?
- A subsection of the DNA
- Genes are made up of DNA. Some genes act as instructions to make molecules called proteins.
What are chromosomes?
A chromosome is a long DNA molecule with part or all of the genetic material of an organism.
Made up of proteins
Where are chromosomes found?
Chromosomes found in the nucleus
How many chromosomes do we have?
46 chromosomes (23 pairs)
Define dimorphic
Humans are dimorphic – exist in two genetic forms
genetic information on the sex chromosomes (X, Y) normally determines male or female development.
XY-MALE
XX-FEMALE
Define sex
Sex (anatomy and biological characteristics)
- Hormonal
- Internal and external genitalia
Define gender
Gender: social role or identity
- Socially constructed norms, roles, relationships
- Can be changed over time and across cultures
E.g. heels, skirts used to be worn by men. Colours associated with girls or boys.
Social gender norms change across time and cultures.
Define Transgender
Transgender: internal gender identity doesn’t match the sex they were assigned at birth. (Non-binary)
What is intersex (hermaphroditism)?
- Mix between female and male genitalia (both vagina and penis)
- XX intersex: chromosomes woman, internal ovaries of woman, but external genitals appear male–> fetus exposed to excess male hormones before birth
- XY intersex: chromosomes of a man, but external genitals incompletely formed, ambiguous or appear female. Internally, testes may be normal, malformed or absent–> problems with testes, problems with testosterone formation, problems using testosterone
David Reimer case
“The boy with no penis”
Circumcision went wrong lost penis 60s
Should’ve undergone an operation and told he was a girl (psychological torture) led him to commit suicide.
Sex Chromosome abnormalities- Turner’s Syndrome
ONLY ONE FUNCTIONAL CHROMOSOME
2nd X chromosome missing/ altered
-affects females (embryo with Y chromosome not viable)
-not inherited(ovaries don’t work properly)
Physical traits
- Shorter than average
- Wide neck/ puffy hands
- Weaker bones/ hearing difficulties
- Ovaries don’t work properly
- Oestrogen / progesterone are reduced—> take hormone replacement therapy
- May not have periods
Sex Chromosome abnormalities- Klinefelter syndrome
Additional X chromosome (XXY)
- Chromosomal disorder in males
- Don’t make enough testosterone(Reduction of testosterone)
- Often don’t make any sperm
- Taller than average height
- Can be increased learning and behavioural difficulties
- Taking hormone replacement can increase muscle strength, body hair, reduce fat on the abdomen, stronger bones.
Hormones and Sexual Development- HYPOTHALAMUS & PITUITARY GLAND
What do they do? In terms of sexual hormones
Hypothalamus releases gonadotropin-releasing hormones (GnRH)
Controls secretion of gonadotropin hormones from pituitary gland:-
- LH (luteinizing hormone)
- FSH (follicle-stimulating hormone)
- In women, LH and FSH encourage estrogen production
- In men, LH encourages testosterone and FSH matures sperm cells
-Lower melatonin (more light) increases gonadotropic secretion.
Offspring born when the most chance of survival
