Please enable JavaScript.

Coggle requires JavaScript to display documents.

Biology Section 3: Reproduction and Inheritance (A (Reproduction…

- - - - sexual
        
        In sexual reproduction two parents create non-identical offspring, inheriting characteristics from both parents.
      - asexual
        
        In asexual reproduction a single parent creates genetically identical offspring.
    - - Gametes are sex cells:
        
        the male one being sperm;
        
        the female one being an egg
        
        When they join together it is know as fertilisation. At this point the fused gametes become a zygote.
        
        the zygot then divides repeatedly, at this stage it becomes an embryo.
    - - structures
        
        insect pollinated
        
        Brightly coloured, larger petals
        
        Nectar
        
        Scents
        
        wind pollinated
        
        Anthers stick out- past other parts of the flower
        
        Stamen will have large surface area.
      - fertilisation
        
        A pollen will travel down the stigma through a pollen tube, in to the ovule in the carpel. Here the pollen will fertilise the ovule, forming a zygote (the seed). The carpel (reproductive organ) becomes a fruit.
      - conditions needed for germination
        
        water
        
        warm temperatures
        
        for enzymes
        
        oxygen
        
        for respiration
      - seed food reserves
        
        Food reserves are in the cotyledons, sustain the plant growth until leaves are able to photosynthesis to support the plant.
      - asexual reproduction
        
        Runners- eg strawberries- a second stem extend, when it reaches the ground cells specialise into root cells and a new plant develops.
        
        Cuttings: a clipping is put in to plant hormones, encouraging the ends to become roots, when placed in soil it will then create another plant.
    - - male reproductive system
        
        Testis- produce sperm cells, they are stored in the epididymus
        
        Vas deference- carries sperm to the penis
        
        The prostate- adds fluid to the sperm, creating semen (as does the seminal vesicles)
        
        The urethra- carries sperm to the end of, and out of the penis.
      - female reproductive system
        
        Ovaries- produce eggs
        
        Oviducts- carry the eggs to the uterus, is the site of fertilisation
        
        Uterus- develops the fertilised egg on the placenta
        
        Cervix- entrance to uterus
      - the menstrual cycle
        
        Oestrogen: produced in the ovaries; thickens the womb lining; prompts the release of LH.
        
        Progesterone: produced in the corpus lutiem; maintains the lining of the womb
      - embryonic development
        
        the placenta
        
        Blood vessels inside the placenta can absorb the digested food molecules and oxygen that the embryo needs to survive.
        
        The embryo can't breath, digest or excrete.
        
        Waste products will be taken out of the embryo and put back into the mothers blood stream for her to excrete.
        
        amniotic fluid
        
        The fluid (mainly water) cannot be compressed- it absorbs pressure- so any force on the uterus wall will not harm the embryo.
      - Pubity
        
        male
        
        Production of sperm
        
        Growth of sexual organs
        
        Body hair- pubic, arms and face
        
        Body mass will increase, including muscle mass
        
        Voice breaks (becomes deeper)
        
        Development of a sexual drive
        
        female
        
        The beginning of the menstrual cycle
        
        Body mass increases and redistributed- to hips and breasts
        
        Body hair- pubic
        
        Voice deepens slowly
        
        Development of sexual organs