lecture1

• What is sexual reproduction?

  Fusion of haploid gametes to form a diploid cell called a zygote
• What are the two types of gametes involved in sexual reproduction?


  Egg and sperm
• What are the advantages of sexual reproduction?

  • Creates genetic diversity within species
  • Provides a natural level of disease resistance throughout species
  • Genetic variation can lead to evolutionary advancements
• What are the disadvantages of sexual reproduction?

  • Competition for females
  • Time and energy required to find a suitable partner
  • Risks of predation, disease, and other calamities during reproduction
• What is asexual reproduction?

  New individuals formed without the fusion of egg and sperm
• What are the mechanisms of asexual reproduction?

  • Binary fission
  • Parthenogenesis
  • Budding
  • Fragmentation
• How does binary fission contribute to prokaryote population growth?

  It allows rapid production of new generations within hours
• What is parthenogenesis?


  Young develop directly from unfertilized eggs of the female
• In which species has parthenogenesis been confirmed?

  At least three species of sharks
• What is budding in asexual reproduction?


  New individuals develop from some generative anatomical points of the parent organism
• What is fragmentation in asexual reproduction?

  A cluster of cells from the original organism can begin growth in a new area
• What are the advantages of asexual reproduction?

  • Fast and easy
  • Offspring carry all of the genes that their parent carried
• What are the disadvantages of asexual reproduction?

  • Offspring's genome closely resembles its parent's, making adaptation to environmental changes less likely
• Which organisms primarily reproduce asexually?

  Bacteria
• What is a reproductive cycle in animals?


  • Cycles of productive activity usually related to seasonality
  • Regulated by environmental cues such as temperature
• What are hermaphroditic organisms?

  • Organisms that possess both male and female reproductive structures
  • Can be sequential hermaphrodites (protandry and protogyny)
• What is protandry in sequential hermaphrodites?

  First males develop into females later in life
• What is protogyny in sequential hermaphrodites?


  First females develop into males later in life
• What is fertilization?


  • Union of egg and sperm
  • Can be external or internal
• What is external fertilization?

  Female releases eggs into the environment and male fertilizes them
• What is internal fertilization?

  Sperm is deposited in or near the female reproductive tract and fertilization occurs within it
• How do organisms ensure the survival of their offspring?

  • Parental care is usually seen in organisms with internal fertilization
  • Some animals retain embryos for part of development in the female reproductive tract
• What are gonads?


  • Organs that produce gametes
  • Not found in all animals (e.g., some worms)
• What is the cloaca?


  A common opening to the outside of an organism
• What are the external reproductive organs in human males?

  • Scrotum
  • Penis
• What are the components of the penis in human males?

  Contains urethra and three layers of erectile tissue
• What happens to erectile tissue during arousal?

  It fills with blood, causing an erection
• What is the role of the testes in human males?

  Produce sperm in seminiferous tubules
• Why must testes be cooler than the rest of the body for sperm production?

  Most mammals produce sperm correctly only at lower temperatures
• What is the function of the epididymis?

  Where sperm complete maturation and become motile
• What is the vas deferens?


  A thick-walled tube that transports sperm cells from the epididymis
• Which vertebrates lack a structure resembling the vas deferens?

  Primitive jawless fish
• What are the accessory glands in human males?

  • Seminal vesicles: secrete fluid contents into ejaculatory ducts
  • Prostate gland: adds secretion to sperm during ejaculation
• What are the external reproductive structures in human females?

  • Clitoris
  • Two sets of labia
• What are the internal reproductive organs in human females?

  Gonads, ducts, and chambers
• What are the ovaries?

  Female gonads that flank the uterus
• What is the function of the oviducts?


  Transport male sperm cells to the egg and provide a suitable environment for fertilization
• What is the uterus?

  A thick muscular organ that extends during pregnancy to accommodate the fetus
• What is the vagina's role in human reproduction?

  Site for insertion of penis and deposition of sperm during copulation
• What are mammary glands?

  Glands that produce milk only in females