reproduction, inheritance, and evolution
male reproductive system
Sperm is made in the testes, it travels up the sperm ducts and fluids and nutrients are added up to make semen. semen travels along the urethra and it is ejaculated from the penis into the female.
the menstrual cycle
day 1-5: lining of uterus sheds
day 6-12: new egg matures, lining thickens
day 13-15: ovulation - egg released
day 16-28: lining maintained
progesterone: inhabits LH, maintains lining
FSH: causes egg to mature
oestrogen: inihibits FSH
LH: causes ovulation
uterus: the womb
cervix: neck of the uterus at the top of the vagina
vagina: sperm is deposited here during sex
ovum: female sex cell ‘egg’
ovary: an egg is released from here every 28 days
oviduct: carries the ovum from the ovary to the uterus
sperm: male sex cell
testes: make sperm continuously
scrotum: sac of skin that holds testes
puberty: the physical changes to the body caused by changes in hormones
placenta: connects the mother and fetus to provide oxygen and nutrients, remove waste products, produce hormones
amniotic fluid: cushion fetus, regulate temperature, provide space for growth
umbilical cord: connection to placenta
gamete: sex cells
heredity
heredity: the process of passing features from individuals to offspring through reproduction
each gamete carries half of the genetic information required to make an offspring. This genetic information is coded in DNA (deoxyribonucleic acid), which is packaged into chromosomes stored in the nucleus of each gamete.
DNA: deoxyribonucleic acid, a chemical molecule that carries the genetic code.
variation
variation: present differences in genetic material - can be caused by dominant and recessive alleles can cause variation.
continuous variation: may have any one of a large range of values
discontinuous variation: can only have one of a fixed number of categories/options
extinct: when no more individuals of a species remain
population: groups of organisms kind living in one place
competition: when two or more living things struggle to gain resources
evolution: theory that animal and plant species descended from past species
biodiversity: variety of living things. the difference between individuals of the same species
natural species: species change over time in response to environmental changes and competition
process of natural selection
variation
advantage
competition
survival
reproduction
inheritance