E Flashcards
What is sex cell specialization in biology?
Individuals that produce large, resource-rich gametes are female (eggs), while those that produce small, mobile gametes are male (sperm). cell
What determines sex in chromosomal sex determination?
The combination of sex chromosomes an individual possesses determines if they will produce eggs or sperm. cell
Define homogametic and heterogametic organisms.
Homogametic organisms have two copies of the same chromosome (ex: XX), while heterogametic organisms have two different sex chromosomes (ex: XY).
What role does the SRY gene play in mammals?
The SRY gene on the Y chromosome activates genes to develop testes and suppress female reproductive structures.
What is Swyer Syndrome?
A condition where an individual is XY but lacks the SRY gene, resulting in female development with non-functioning ovaries.
How does sex determination work in fruit flies?
One X chromosome (XO, XY, XYY) results in a male, while two X chromosomes (XX, XXY) result in a female.
What is a dioecious plant?
A plant species where individuals are either exclusively male or female.
What is the ZW sex-determination system?
In ZW systems, females are heterogametic (ZW), and males are homogametic (ZZ). Found in birds, butterflies, some reptiles, and fish
How does the XO sex determination system work?
Males have one X chromosome (XO), while females have two X chromosomes (XX), as seen in grasshoppers and crickets.
What is UV sex determination in mosses?
Spores carry either U or V chromosomes; U spores grow into female plants, and V spores grow into male plants.
How does temperature influence sex determination?
Species like crocodiles and turtles have sex determined by incubation temperature during a thermosensitive period.
What are the three patterns of temperature-dependent sex determination (TSD)?
TSD la: Males at low temperatures, females at high. TSD IB: Females at low temperatures, males at high. TSD II: Females at mid-temperatures, males at low and high.
What is an example of climate change affecting sex determination?
Australian bearded dragons have switched from chromosomal sex determination (ZW) to temperature-based sex determination.
How does food availability influence sex determination?
Species like the Red knot nematode become male in low food.
How does social context determine sex?
Species like green spoonworms and clownfish change sex based on their social environment.
What is the difference between protogyny and protoandry?
Protogyny: female first (ex: Blue-headed Wrasse). Protoandry: male first (ex: Clownfish)
What is bidirectional sequential hermaphroditism?
When an individual can switch back and forth between sexes multiple times.
How does haplodiploidy work in social insects?
Unfertilized eggs develop into haploid males, and fertilized eggs develop into diploid females (ex: bees, ants, wasps).
What is the role of the Y chromosome in fruit flies?
The Y chromosome contains genes for making sperm but does not determine sex.
What is the function of the Testes determining factor (TDF)?
A transcription factor encoded by the SRT gene that triggers the development of testes.
What is the significance of silene latifolia in plant sex determination?
It is a dioecious plant where genes on the Y chromosome repress female genes and activate male genes.
How do green spoonworms determine sex?
If a larva lands alone, it becomes female. If it encounters a female, it becomes male and lives inside her body.
Why do larger females exist in many species?
In some species, larger females produce more offspring, making it beneficial to be female under high-resource conditions.
What is an example of sex change in fish?
Blue-headed Wrasse changes from female to male when the dominant male is removed.
