| A | B |
|---|
| extinction | when a species has died out |
| reproduction | process which prevents extinction |
| hypothesis | a question which can be answered using experiments |
| data | results from an experiment |
| prediction | when you say what will happen if the hypothesis is right |
| offspring | the products of reproduction |
| gametes | sex cells |
| human male gamete | sperm |
| human female gamete | egg |
| fertilisation | fusion of nuclei of female and male gametes |
| external fertilisation | when fertilisation happens outside the body |
| internal fertilisation | when fertilisation happens inside the body |
| testes | organ where sperm are made |
| scrotum | 'bag' which holds testes |
| semen | mixture of sperm and fluids |
| urethra | carries urine and sperm in males |
| circumcision | removal of the foreskin |
| foreskin | protects the head of the penis |
| acrosome | front part of a sperm cell which contains enzymes |
| sperm tails allow | movement to reach an egg cell |
| egg cells are produced | by the ovary |
| menopause | when a female stops producing eggs |
| oviduct | egg tube |
| the oviducts are lined with | cilia |
| the cervix opens into the | vagina |
| embryo | a ball of cells |
| implantation | when an embryo buries into the lining of the uterus |
| uterus | womb |
| fertilisation occurs in the | oviduct |
| the embryo is protected by the | amnion |
| placenta | a plate shaped organ attached to the uterus lining |
| oxygen, water and 'food' pass from | mother to embryo |
| waste, including carbon dioxide pass from | embryo to mother |
| organ which carries the embryo's blood to and from the placenta | umbilical cord |
| test-tube babies are born using | IVF (in vitro fertilisation) |
| the gestation period in humans is | 40 weeks |
| foetus | formed when an embryo has a full set of organs |
| ultrasound scans | produce images of the foetus |
| a premature birth is when | a baby is born early |
| labour | when the uterus starts to contract |
| afterbirth | when the placenta breaks away and leaves the mother |
| antibodies | substances which help prevent diseases caused by microorganisms |
| puberty is caused by | hormones |
| adolescence | a period when emotional and physical changes occur |
| the menstrual cycle lasts | 28 days |
| ovulation | when an egg is released |
| ovulation happens on | day 14 |
| a period usually lasts for | 3-7 days |
| life cycle | the changes in an organism from birth until it is able to reproduce |
| studying reproduction can | help endangered species |
