Reproduction and inheritance

• What are the two main types of reproduction?

  Sexual and asexual reproduction
• What is a key advantage of sexual reproduction?


  It produces variation in offspring
• How does variation in offspring benefit a species?


  It increases the likelihood that some individuals will survive environmental changes
• What is a survival advantage?


  A characteristic that allows an organism to survive in a changing environment
• How does sexual reproduction decrease the chance of extinction?


  Variation decreases the chance of the whole species becoming extinct
• What is a key advantage of asexual reproduction?


  Only one parent is needed
• How does selective breeding work?


  It mixes genetic information from two organisms to produce offspring with desirable characteristics
• What is the benefit of using selective breeding?


  It speeds up natural selection
• Give an example of selective breeding.


  Breeding two animals with lots of meat to increase food production
• What is the energy requirement for asexual reproduction?


  It uses less energy and is faster as organisms do not need to find a mate
• What is the outcome of asexual reproduction in favorable conditions?


  Lots of identical offspring can be produced
• What is fertilization in reproduction?


  The fusion of a male and female gamete to produce a zygote
• What does a zygote develop into?


  An embryo
• What are the two types of pollination in plants?


  Insect-pollinated and wind-pollinated
• What are the adaptations of insect-pollinated plants?


  • Large and bright petals to attract insects
  • Scented nectar to attract insects
  • Sticky pollen grains in moderate amounts
  • Stiff anthers inside the flower
  • Sticky stigma inside the flower
• What are the adaptations of wind-pollinated plants?


  • Small and dull petals, usually green or brown
  • No scent or nectar
  • Smooth and light pollen grains in large amounts
  • Loose anthers outside the flower
  • Feather-like stigma outside the flower
• What are the male and female gametes in plants?


  Pollen grains are the male gamete, and the ovule is the female gamete
• What happens when pollen grains land on the stigma?


  A pollen tube grows down the style into the ovary
• What is formed when the male nucleus fuses with the female egg nucleus?


  A zygote is formed
• What does the zygote undergo to form a seed?


  Mitosis
• What does the ovule become after fertilization?


  The seed
• What does the ovary become after fertilization?


  The fruit of the plant
• What are the conditions needed for seed germination?

  • Water: activates enzymes to break down starch
  • Oxygen: needed for aerobic respiration
  • Warmth: optimum temperature increases growth rate
• What is the method to test conditions for seed germination?

  Set up boiling tubes with cress seeds under different conditions
• Which test tube will show germination and why?


  Test tube B will show germination because it has water, temperature, and oxygen
• What are the structures of germinating seeds and their descriptions?


  • Embryo: young root and shoot become the adult plant
  • Food store: starch for the plant until it can photosynthesize
  • Seed coat: protective covering
• What does asexual reproduction produce?


  Clones, as it only involves one parent
• What is an example of natural asexual reproduction?


  Runners in strawberry plants
• How are artificial cuttings made?


  Tissue samples are scraped from the parent plant and placed in agar with nutrients
• What does the male reproductive system produce?


  Semen that contains sperm cells
• Where are sperm produced?

  In the testis
• What is the function of the penis?


  It passes urine and semen out of the body
• What is the role of the urethra?


  It carries urine or semen out of the body
• What do ovaries contain?


  Ova (female gametes)
• What is the function of the oviduct?


  It connects the ovary to the uterus and helps transport the ovum
• What is the purpose of the uterus?


  It has a thick lining for fertilized eggs to implant
• What is the role of the cervix?


  It ensures the fetus remains in place during pregnancy
• What is the function of the vagina?


  It is a muscular tube leading to the inside of the body
• What are the secondary sexual characteristics in females due to oestrogen?


  • Breast development
  • Menstrual cycle begins
  • Growth of body hair
  • Widening of hips
  • Increased height
• What are the secondary sexual characteristics in males due to testosterone?


  • Growth of penis and testes
  • Production of sperm
  • Growth of facial and body hair
  • Muscle development
  • Voice lowering and breaking