Transcript SURVIVAL
SURVIVAL © T. P. Thould April 2000 FERTILIZATION For many plants and animals species to survive they need to reproduce by Sexual Reproduction. This involves a Male and a Female each making a sex cell which can join together ( FERTILIZATION )and form a new individual. THE MAIN PARTS OF A FLOWER Petal Stigma Anther Style Stamen Carpel Filament Ovary Sepal Ovule Test THE FUNCTIONS OF THE MALE PARTS Anther Stamen Makes pollen which has the male genes in it Filament Different plants have different numbers, shape and sizes of Stamens Holds the Anther up in the air so that visiting insects brush against it Test THE FUNCTIONS OF THE MALE PARTS Stamen Different plants have different numbers, shape and sizes of Stamens THE FUNCTIONS OF THE FEMALE PARTS Stigma Style Carpel Ovary Test Ovule A sticky surface where pollen stays when visiting insects brush against it. Guides the pollen tube down to the Ovary. Makes the Ovules which contain the female genes. Forms the fruit. POLLINATION Before fertilizion can take place. The pollen grains carrying the Male Chromosomes must get to the female part of the flower I.e. from the Anther to the Stigma. This is POLLINATION Anther Stigma POLLINATION POLLINATION can be by Insects, in which case the flowers are brightly coloured and smell. If the flowers are dull and not easily seen then their pollen is carried by the Wind Anther Stigma POLLINATION POLLINATION can be either Self or Cross SELF is when the Anther and Stigma are on the same plant. CROSS is when they are on different plants Anther Stigma FERTILIZATION PLANTS have flowers which have male and female parts that make the male and female sex cells. The male part ( Stamen ) makes the POLLEN The female part ( Carpel ) makes the OVULE Pollen + Ovule = Seed Fertilization Stigma Style Ovary Once Pollination has taken place, the Pollen grain grows a tube carrying the Male Chromosomes , down the Style and through the Ovary wall. The Male Chromosomes join with the Female Chromosomes in the Ovule. This is FERTILIZATION Ovule Pollen Tube FERTILIZATION Pollen Carries the Male Chromoso mes in its Nucleus + Ovule Contains the Female Chromoso mes in its Nucleus These are each a HALF SET of Chromosomes so that when they join together they form a WHOLE SET in the seed. = Seed A Fully Fertilized Ovule SEED DISPERSAL Most plant have a way of dispersing their seeds so that they germinate and grow well away from the parent plant. WHY? SEED DISPERSAL Two ways some plants use to disperse their seeds is by:- 1. Animals 2. Wind Solution How could the above seed be changed so that it could be dispersed by a) An Animal b) The wind SEED DISPERSAL How are these seeds dispersed - what is it about them that gives you the answer? A B GERMINATION Once the seeds have been dispersed they need the right conditions to start growing into a new plant - Germination. These conditions are:•Warmth •Moist •Air •Light/Dark THESE ORGANS HELP WITH REPRODUCTION The male sex organs are made up from the Penis, Testes and Scrotum. The Testes make Sperm which contain the male genes. The Penis places the sperm as near as it can to the female’s egg ( Ovum ) The female sex organs are made up from the Ovaries, Vagina, Uterus and Oviduct. The ovaries make the Ovum which contains the female genes. The Uterus ( womb ) holds the developing baby. THE MALE SEX ORGANS Pubic Bone Erectile Tissue Bladder Seminal Glands Sperm Duct Penis Testicle THE FEMALE SEX ORGANS Oviduct Ovum released from the ovary into the Oviduct Ovary Uterus or Womb Cervix Vagina FERTILIZATION Sperm Carries the Male Chromoso mes in its Nucleus + Ovum Contains the Female Chromoso mes in its Nucleus These are each a HALF SET of Chromosomes so that when they join together they form a WHOLE SET in the seed. = Foetus A baby with a full set of Chromosom es THE MENSTRUAL CYCLE Every month once puberty has been reached, an egg or Ovum is released from one of the ovaries in the female. This is called Ovulation. If the Ovum is not fertilised then it leaves the body through the Vagina along with the lining of the Uterus which had become thicker and richly supplied with blood. This happens every month and is known as a Period or Menstrual Cycle. THE MENSTRUAL CYCLE Oviduct Week One An Ovum is made in the Ovary ready to be released into the funnel of the Oviduct. Ovary Uterus Vagina THE MENSTRUAL CYCLE Week Two The Ovary releases the Ovum into the funnel of the Oviduct. This is Ovulation. The Uterus wall thickens ready for the fertilised Ovum THE MENSTRUAL CYCLE Week Three The Ovary travels down the Oviduct towards the Uterus. The wall of the Uterus is well supplied with blood. THE MENSTRUAL CYCLE Week Four As the Ovum was not fertilised, the Uterus wall is shed with the Ovum the Period. Day 28 Day 7 THE MENSTRUAL CYCLE Day 21 Day 14 THE MENSTUAL CYCLE Once the period has finished the whole cycle begins again and continues each month as long as the Ovum is not fertilised. To prevent the fertilisation of the Ovum many couples take precautions which stoops the Sperm reaching the Ovum - Contraception EARLY PREGNANCY The Embryo ( baby ) is held in the wall of the Uterus and is joined to the Placenta by the Umbilical Cord. The baby gets food and oxygen from the mothers blood through the Placenta. It also gets rid of waste into the mothers blood through the Placenta THE PLACENTA The Umbilical Cord carries food and Oxygen to the baby and waste away. Food and Oxygen in the mothers blood Placenta Waste food and Carbon Dioxide THE PLACENTA The Placenta forms a barrier between the blood of the mother and the baby but allows substances to pass between them. Placenta THE PLACENTA Unfortunately, some harmful substances can pass from the mothers blood into the baby e.g. Alcohol, Drugs, Nicotine and AIDS Placenta THE AMNION This is a bag that surrounds the baby and is filled with a fluid which protects the baby from bumps and bangs. Placenta The Amnion NINE MONTHS LATER Placenta or Afterbirth Cervix The baby is ready to be born. The head is engaged - in the right position for birth, at the mouth of the Uterus, the Cervix.