Plant Reproduction and Flower Anatomy

• Reproduction involves the processes that create more of the same kind of organism.

Types of Reproduction

• Sexual reproduction includes two parents.
• Asexual reproduction includes only one parent.

Asexual Reproduction

• Asexual reproduction produces new, genetically identical offspring from one parent without the production of gametes.
• Gametes are the sperm and egg that fuse together to produce a zygote which then divides to create a new organism.
• Sperm are male gametes and ovum are female gametes.

Types of Asexual Reproduction

• Binary fission
• Reproduction by spores
• Budding
• Reproduction by tubers

Binary Fission

• Bacteria reproduce by cell division (fission), where a bacterial cell divides into two, with each daughter cell becoming an independent bacterium.
• Cell division in bacteria can occur every 20 minutes, resulting in a large colony in a short time.

Reproduction by Spores in Fungi

• Fungi that reproduce by spores have aerial hyphae and rhizoids.
• Aerial hyphae contain sporangium and sporangiophore.
• Sporangium contains spores.
• Fungi produce spores in sporangia, which burst and spores spread by wind.
• Spores that land on food under suitable conditions germinate and form new fungi.

Budding in Yeast

• Budding diagram illustrates the process of a new yeast cell forming as a bud on a parent cell, eventually separating to form an individual cell or a chain of cells.

Asexual Reproduction in Potatoes

• A tuber is a short underground stem or root, usually enlarged, with a storage function.
• Potato tubers have grooves called eyes, each containing a bud with a scale leaf.
• Buds grow using stored food in the tuber, producing a new shoot and root in favorable conditions.
• Underground side stems grow from the base of the main stem, store food, and form new tubers.
• The leaves, stems, and old tuber die, but the new tubers remain dormant until conditions are favorable.

Advantages and Disadvantages of Asexual Reproduction

• Asexual reproduction is often rapid because there is no need to find a mating partner.
• Identical strains are produced, which is useful if parents have good traits.
• Asexual reproduction can withstand unfavorable conditions using stored food.
• Beneficial traits are maintained without variation.
• Rapid reproduction can be harmful if organisms produce diseases.
• Lack of variety can cause organisms to die if the environment changes and they cannot adapt.
• Harmful genes are transferred, and overcrowding leads to competition for resources.

Sexual Reproduction

• Sexual reproduction involves the fusion of haploid nuclei to form a diploid zygote and the production of genetically different offspring.

Advantages and Disadvantages of Sexual reproduction

• New varieties are produced that can adapt to environmental changes.
• Sexual reproduction allows for the evolution of species.
• Harmful genes in parents are not necessarily handed on to offspring.
• Slower than asexual reproduction, therefore it does not lead often to overcrowding.
• Excellent individuals produced by sexual reproduction cannot give identical offspring.
• It is a slow process which leads to the production of few offspring which is a disadvantage in organisms useful to humans such as food-producing organisms.

Reproduction in Plants

• Key parts of an insect-pollinated flower include sepals, petals, stamens, filaments, anthers, carpels, style, stigma, ovary, and ovules.
• Self-pollination is the transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant.
• Cross-pollination is the transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species.

Function of Flower Parts

• Receptacles are the enlarged, extended part of the stem that carries the flower.
• Sepals are small and green, protecting the flower while closed.
• Petals are large, colored, and sometimes scented to attract insects for pollination and provide a landing platform, also they surround and protect the reproductive organs.
• Stamen include each anther and the filament.
• Anthers contain pollen sacs for producing pollen grains with male gametes in flowering plants.
• Filaments carry and hold the anther to be exposed to pollination agents.
• Carpels consists of the stigma, style, and ovary.
• The stigma receives pollen and produces nutritive materials for pollen germination.
• The style holds the stigma to expose it to pollination agents.
• The ovary produces ovules containing female gametes in flowering plants.
• The nectary gland which makes a sugary solution called nectar used by insects as food.

Steps in Flowering Plant Reproduction

• Pollination, is the transfer of pollen grains from anther to a stigma.
• Fertilization, is the fusion of the male gamete and female gamete to form a zygote.

Types of Pollination

• Self-pollination is the transfer of pollen from an anther to the stigma of the same flower or another flower on the same plant
• Cross-pollination is the transfer of pollen from an anther of one flower to the stigma of another flower on a different plant of the same species

Characteristics of Self- and Cross-Pollinated Flowers.

• Self-pollinated flowers are hermaphrodite (bisexual, with both male and female organs), have male and female organs maturing at the same time, stamens longer than carpels, and male and female organs ripening before the flower opens.
• Cross-pollinated flowers may be unisexual or bisexual, mature male and female organs at different times, have stamens shorter than carpels, male and female organs ripen the flower after opening, and have stigmas secreting chemicals that kill foreign pollen.

Implications of Self-Pollination

• Self Pollinated plants produce less variation, plants with the same good strain will be able to produce offspring of a good strain also.
• A disadvantage if there is a change in the environment is that they will be unable to adapt.

Implications of Cross Pollination

• Cross Pollinated plants are more varying so natural selection and evolution is more likely to occur.
• Also a disadvantage in that good strains are not guaranteed.

Agents of Pollination

• Means of pollination include wind, animals, humans, and insects.
• Insect-pollinated flowers are usually large, appear in warm times, and have a scent to attract insects. They have nectary glands to secrete nectar, and reproductive organs are enclosed within the flower so insects must brush against them to reach the nectar gland.
• Pollen grains of insect-pollinated plants are sticky to cling to insects, small in number, and larger than those spread by wind.
• Wind-pollinated flowers are usually small, appear in cold weather, and are not scented. Their reproductive organs are projected outside the flower.
• Pollen grains of are dry, small, and light to be carried by wind.
• Wind pollinated plants have a large amount of pollen, since most is lost. and have feathery stigma to trap pollen grains from air.
• When a pollen grain lands on the stigma, the stigma produces a sticky nutritive fluid.
• The pollen grain absorbs this fluid, producing a pollen tube, and the nucleus of the pollen grain (male gamete) passes through the tube.

Flower Fertilization

• The pollen tube grows towards the ovule, reaching the micropyle where the male nucleus passes to the ovule.
• The nucleus of the pollen grain fuses with the nucleus of the female gamete.
• The ovule develops into a seed.
• The integument becomes the testa of the seed.
• The ovary enlarges and becomes the fruit.
• The wall of the ovary becomes the pericarp.

Functions of the Fruit

• Protects the seed
• Helps dispersal
• Stores food

Structure of Non-Endospermic Seed

• The testa is non-permeable and becomes soft and ruptures during germination
• The cotyledons store food
• The radical grows and produces a young root
• The plumule grows and produces a young shoot
• The micropyle is the pathway where water enters the seed

Seed and Fruit Dispersal

• Seed and fruit Dispersal is the spreading out of seeds and fruits.
• Dispersal avoids overcrowding and increases the chance of spreading diseases, avoids comptetition of water and minerals, allows species to increase in different areas in population.
• Dispersal can be a disadvantage since it allows the spread of plants which can carry undesirable properties.
• Seeds and fruits may not be able to grow in all locations.
• Allows undesirable plants to compete between crops.
• Tomatoes, apples, and strawberries have indigestible seeds or fruits and therefore indigestible parts are evacuated through stool to germinate when they were eaten by an animal.

Germination Stages

• The seed takes up water via the micropyle.
• The cotyledons swell and the testa bursts.
• The enzymes become active by the effect of water.
• The enzymes digest the stored food in the seed.
• The digested food diffuses through the embryo and is used up in growth.
• The radical emerges from the testa.
• The testa falls off.
• The plumule opens up and grows into a shoot.

Germination Conditions

• Water activates the enzymes in the seeds, transports salts from the soil to the shoot, expands the vacuoles of newly formed cells causing the root and shoot to grow, and transports sugars for the cotyledons to the growing regions.
• Oxygen is used in aerobic respiration, providing the embryo energy for different metabolic reactions.
• A suitable temperature (35–40°C) is required to make the enzymes in seeds to become active.
• The dry mass decreases at the beginning of germination.

Changes in Seed During Germination

• The dry mass decreases as the embryo breaks down stored food to release energy for metabolic activities.
• The fresh mass increases due to water absorption.
• The dry mass increases beginning several days after germination, because green leaves may be formed to make food in photosynthesis.

Reproduction in Humans

• Internal Fertilization: gametes fuse inside the body of the female in the human model.
• Internal Development: the development of the embryo grows inside the human female's body.
• Ganads: the organs resposible for producing gametes.
• Male ganads are testes, female ganads are ovaries.

Female Reproductive System

• Ovaries: there are two, right one and left one, their function is the production of ova (singular: ovum), production of female hormones called (estrogen), each ovary produces an ovum per 2 months (56 days), therefore there is only one ovum produced every 28 days by one of the two ovaries).
• Oviduct (Fallopian Tubes): this front part is a funnel-shaped structure to rrecieve ova (this part is called funnel of the oviduct), cilia is also contained to push the ova into the uterus, the site of the eggs fertilization (the ovum dies when leaving).
• Uterus (Womb): a muscular organ, the site where in the embryo is developed if the ovum is fertilized, consists of a muscular wall and lining.
• Uterus Lining: The uterine lining is soft and spongy with many blood vessels which is used to supply the embryo with all its requriements, with implantation (when the embryo fixes itself to the lining).
• If there is no fertilization, the lining will break down and start bleeding like with menstruation. Each month a new lining is developed.
• During birth contractions occur to help push the fetus out.

Male Reproductive System

• Testes produce sperm, and produces the make sex hormone known as testosterone.
• Scrotum or scrotal sac is an ac of skin used to hold the testes outside the body at a lower temperature because high temperatures affect sperm procuction.
• Epididymis are coiled tubes that store sperm and contracts to help in ejaculation of sperms.
• Sperm ducts conduct sperm from the epididymis to the urethra and allows peristalsis to aid in ejaculation.
• Urethra is a common passage for both urine and semen, mucus acts as an aid for ejaculation.
• Also used to pass urine but cannot take place during ejaculation because muscular bladder is contracted during ejaculation.

• The seminal vesicles and prostate create fluid known as seminal fluid to mix with sperm and consists of the right nutrients, and a mucus for copulation, sugars to give the s perms energy, and an alkaline to neutralize acid from urine in the urethra.

• The penis contains erective walls which when stimulatd get pumped with blood making the penis long enough to copulate making the penis known as the organ of copulation. Where the penis is circumsized taking off the fore skin.

Sperm Adaptive Features

• Nucleus carries genetic information needed
• An organelle called an acrosome contains enzymes to penetrate to ovum
• Has Mitochondria to produce the energy source needed to fuel movement to find ovum
• Has tail (flagellum) used for movement

Ovums Adaptive Features

• Contains stored to be used in ovulation
• Contain jelly to prevent additional sperm inside
• Male gamete (sperm smaller and mobile with flagella and an acrosome.
• Female gamete (ovum) larger and non-motile with a jelly coat.
• Seamen deposits into the vagina where the sperm enters the cervix and then tails them to the cervix and through the film for moisture lining the uterus.
• Sperms are attracted to the ovum by specific chemicals.
• Many sperms make it to the egg, each one needs an enzyme to start disgest itself.

Fertilization

• Semen is deposited at the top of the vagina.
• Sperms swim using their tails through the cervix and the film of moisture lining the uterus.
• Sperms swim towards the Ovums due to specific attractants via chemicals.
• When the sperm penetrates a digestive enzyme is produce.
• The sperm leaves its tail outside and joins its nuceluses together producing a zygote.
• An egg can only have one sperm at a time, there is a protective layer called a membranous covering called, it is made once a sperm has fertilzed the egg to prevent any additional sperm from the ovum.

Terms

• Zygote: A cell formed due to the fusion of a male gamete and a female gamete.
• Embryo: A ball of cells formed due to the division of the zygote by Mitoses (cell replication).
• Fetus: A mammalian embryo in fairly advanced stage of development.
• Ovulation: Means the release of an ovum into the oviduct.

Menstruations

• Menstruation refers to the lining and breakdown of the uterus because fertalization did not occur. The breakdown is caused by a hormone called progesterone which maintains the lining of the uterus.

Stages:

• Pituitary Gland release FSH hormones which make eggs or ovum with an egg sac to develop a Graafian follicle.
• The eggs secrete a hormone called estrogen which prevents more eggs from developing.
• Pituitary Gland produce LH hormones which pop the egg into oviduct.
• Eggs and follicl are know know as corpeus luteum that secrete progesterone and start thickening everything until fertalization occurs.
• Follicule, LH, and FSG start slowing decline.
• If the EGG gets FERTALIZED corpeus luteum gradually disappears, no more progesterone secreted uterus lining breaks down, and then menstration occurs

If Fertilization does Occur

• Implantation takes place and allows the growing to occur
• After the baby has been born, the cycle will start over becuase the production of the prosterone.
• The development of the Amnion Sac in the womb. Used as cushion that acts as a shock absorbment.
• Protective to baby growing.
• Creates suitable temperature.
• Helps with free movement.
• Removes all bacteria from the area.

Development of Placenta

• The Cells of the embryo will fix into the uterus through small projections called villi, and they will eventually grow inside.
• The Maternal blood goes from the uterine artery and gets transferred to the fetus creating a chord.

Placenta importance

• Oyxgen being transferred to fetus
• Removes carbon dioxide from the fetus and diffused the lungs Transfers food to the mother via glucose, and amino acids will also be used for uptake via the fetal blood.
• Waste products such as urea are removed.
• Prevents blood agglutiation preventing mother and babys blood to mix.
• Protects fetus from disease passed from blood, bacteria, and pressure. Not from most viruses though.

The Umbilical Chord

• Connects to the placante
• Holds all the blood (oxygen and carbon dioxide)
• Helps with circulation

Sexually transmitted diseases

• Sexually transmitted infections (STIs) are diseases spread through sexual contact.
• HIV/AIDS is caused by the human immunodeficiency virus (HIV), which lives in blood and other bodily fluids, damaging T-lymphocytes and decreasing immunity.
• HIV/AIDS are transmitted via sex.

Fertility Drugs

• Fertility drugs stimulate the ovaries to make multiple eggs, which can lead to many problems and cause the parents to get a lot of hormone problems in return, can also decrease fertility. Multiple baby pregnancies occur.

Artificial Insemination

• Artificial insemination is the process of fertilization by inserting a donors sperm into the womb to fertalize, a new sperm to fertalize. When using the artificial inseminaiton method the parent has to be acceptence of the chils disownment if the sperm is not of their orgin. Its mainly ised for those with fertility isuses.
• The sperm are left inside for a bit to grow and become easliy implamted since larger.
• Aids those with blockage from fertalizing
• A donor sperm can also aid where the male cannot produce health sperm.

Some bad include:

• Highers the stress level for the sperm.
• Expensiive
• Has ethical issue

Sex Hormones

• Male sex hormone (Androgen). and Female sex hormone (Estrogen)
• Testostorone is an example of such. The functions include the development of sex organs, muscles develoupment etc.

Female Sex Hormones

• Female sex hormone (Estrogen).
• Ovulation, menstration causes the hips and breats to grow.

Used of Hormones in Fertility

• Hormone treatmenrts with the hormones LH FSH and even medication such a clomid can help those fertalize.

Progesterone

• Progesterone can help the uterus to take eggs from female.
• Testostorone is helpful fro the males that can stimulate sperm production.

Test your knowledge of plant reproduction, including fertilization, seed development, and flower anatomy. Questions cover the roles of pollen tubes, ovules, ovaries, and adaptations for pollination and seed dispersal. Explore the importance of petals, sepals, and the differences between self-pollination and cross-pollination.