Biology Module 5 - Heredity Revision Flashcards
Why do we need reproduction?
For the continuity of species as we have finite lifespans.
Asexual Reproduction and methods.
Individuals who create exact copies of their genetic material, replicated through mitosis.
Methods: Budding, Binary/multiple fission, spores.
Sexual Reproduction
Occurs between 2 genetically different parents, where their haploid gametes fuse into a zygote, creating a variation through their offspring.
Reproductive Success
Producing fertile offspring to survive reproductive maturity and produce offspring of their own.
Biological Fitness
To contribute to the gene pool from a certain genotype where their allele/gene variant is present in the future.
Biological Fitness (Simple definition)
The more offspring you produce, the better your biological fitness.
How to ensure success for gametes to meet.
The ovum and sperm should be in a moist environment at close proximity. Dehydration kills/falters performance of gametes.
Methods of Aquatic and terrestial organisms ensuring gamete fusion.
Aquatic/amphibian organisms breed in mating rituals in the ocean.
Terrestrial organisms release internally due to the lack of environmental moisture.
3 Mammal types
Monotreme - Lays eggs
Marsupial - Stores young in pouch
Placental - Develops from placenta nutrients
External Fertilisation
Occurs openly by aquatic animals.
- Parents releases mass gametes for highest chance of fertilisation.
- Usually done in mating rituals to ensure proximity at a concentrated area.
External Fertilisation - Example
Sessile (non-moving) animals such as oysters and coral have mass spawnings (usually full moon, high tide - natural phenomena) as a mating ritual for fertilisation.
External Fertilisation - Positives
Fast, prolific development, using minimal energy and females can still produce during development. Young disperse naturally reding infraspecific competition.
External Fertilisation - Negatives
Excess use of gametes with limited success, requiring mass gametes exposed to predators, disease, currents and environment generally.
Internal Fertilisation
Parents produce from copulation after courtship is achieved, male inserts penis (mammals/reptiles) to release gamete to fertilise ovum. A zygote is formed from the fusion.
Internal Fertilisation - How do insects attract mates.
Produce ‘pheremones’ to attract mates.
Internal Fertilisation - Courtship
Emotional connection, needed for; Flat/earthworms, insects, reptiles, mammals and birds.
Internal Fertilisation - Advantages
High success from inclosed proximity of less gamete use, young are protected and given nutrients internally for survival.
Internal Fertilisation - Disadvantages
Requires courtship, slow development with mass energy use by female and young is cared for after birth.
Maternal, Paternal - Vertebrates, Invertebrates
Maternal - Mother
Paternal - Father
Vertebrate - Backbone
Invertebrate - No Backbone
Human Chorionic Gonadotrophin
Stimulates the corpus luteum (later placenta) to make progesterone for pregnancy.
Lutenising Hormone
Stimulates testes to create testosterone.
Assists progesterone release after ovulation via the corpus luteum.
Where is HCG, FSH & LH made?
The Piturity Grand in the brain creates HCG to then create FSH and LH.
Oestrogen
Primary, involved with secondary sex characteristics (puberty) in females.
Thickens the endometrium and lubricates vagina in menstrual cycle.
Matures Sperm.
Develops baby organs and functions the placenta.
Progesterone
Surrounds the Cervix and uterus for acrosomes to climb and reach the ovum.
If implantation is successful, the corpus grows to then be replaced by the placenta, failure cause it to degenerate.
Progesterone (Simple Definiton)
Supports menstruation and maintains the early stages of pregnancy.
Androgen
Secondly Sex Characteristics for males.
involved in the initiation and maintenance of spermatogenesis.
Oxytocin
Stimulates uterine contractions during labour as well as breastmilk flow after birth.
Relaxin
Relaxes muscles, ligaments and joints for the growing foetus, stretches the body.
Endorphin
Relieves pain to increase concentration for labour.
Features of Fertilisation - General
Requires gametes to meet and combine - created originally from Gametogenesis.
Fertilisation occurs in the fallopian tube, creating a zygote from fusion - continuity through variation.
Stages for successful fertilisation.
- Formation & maturation of gametes
- Spermatozoa must journey in the oviduct
- Spermatozoa fuses through contact with ovum
Features of Fertilisation - Male
Needs spermatogenesis, assisted by testosterone (made in testes, assists in production) and oestrogen (assists in maturing cells)
Features of Fertilisation - Process in female
Acrosome will detach from the flagellum to journey up the uterus.
Passes through 3 barriers of the egg (corona radiate, zona pellucida and then egg membrane (follicle cells still attached act as enzymes, assisting sperm to cross).
Only 1 sperm enters, electric current prevents others. The final fusion creates successful implantation.
Cell division begins to form a blastocyst, gametes must be of the same species.
Features of Implantation
The zygote sticks to the wall of the reproductive tract as the most suitable environment.
The blastocyst implants to the uterine wall to access nutrients and develop into an embryo - blood vessels surrounding blastocyst carries blood with dissolved nutrients.
Embryo develops into a foetus after 5-11 weeks.
Embryo becomes a new organism after birth.
Plant Reproduction - Male, Female and no-gender reproductive parts.
Male parts/Stamen
Anther: Where pollen forms
Filament: Stalk holding the anther
Female parts/Pistil
Stigma: Sticky surface to catch pollen
Style: Binds the stigma to ovary.
Ovary: Holds/forms ovules here
Ovule: Organ that forms seeds (flowing plants)
No-gender:
Petals: Modified leaves to attract pollinators.
Receptacle: Reinforced the base supporting reproductive structures.
Sepals: Modified green leaves that protect unopened flowers/buds.
(Flowering) Plants - Sexual Reproduction
When pollen sticks to the stigma, it travels down the newly formed pollen tube to fuse with the ovule - creates an embryo/seed with its exterior developing into a fruit.
After fertilisation, seeds will disperse from the ovary, either as dry of fleshy fruits.
Plants - Dry and fleshy fruits
Dry fruits (banksia, pinecones) use explosive mechanisms to disperse seeds over time.
Fleshy fruits (apple) require a biotic agent to eggiest seeds for dispersal.
Plants - Cross and Self pollination
Cross pollination brings one plants pollen to another creating variation.
Self pollination uses less energy and no pollinators, producing through mitosis.
Plants - Angiosperms and Gymnosperms
Angiosperms are flowering plants. Most are wind pollinated - small , green, odourless, petal less flowers in large numbers with light pollen to travel - highly inefficient.
Other variants use pollinating agents - Like bees, they are attracted to rewards (nectar), pollen attaches to the pollinating agent and makes contact to another stigma due to it.
Gymnosperms have no flowers, with seeds being directly expose (cones). Microspore from male cone will enter female in the pollen tube to reach the megaspore in the ovule, once fertilised the variation is formed and dispersed.
Plants - Germination
The embryo is dormant and dehydrates to survive varying conditions. It will germinate when it finds; nutritious soil, water and warmth. Creating a Radicle Root for water/nutrients then a Plumute for photosynthesis to then develop further.
Plants - Asexual Reproduction: P/N and Vegetative Organs
Done by organisms well adapted, disadvantages in how offspring are identical, great risk of eradication.
Some vegetative organs include:
Stolons: Strawberries (Develop plantlets)
Rhizomes: Ginger
Bulbs: Onions (storage organ)
Tubers: Potatoes
Suckers: Roses
Regeneration and Fragmentation: Sea Sponges (Part breaks off and grows new individual (cuttings))
Spores: Mushrooms
Plants - Peremating Organs
Roots/stems which store nutrients in a large dormant wooden vessel to survive adverse conditions by seasons until safe to develop/regrow.
Reproduction - Fungi Definition
Eukaryotic organisms that secrete enzymes to break organic matter and absorb nutrients (mushroom, yeast, moles, truffles), releasing; carbon, nitrogen, oxygen, phosphorous.
Reproduction - Fungi reproduction process
- The sporophores use mitosis (sometimes meiosis for instant variation, depends on species) to release spores that grow without fertilisation.
- Mycelium does mitosis to extend roots, releasing pheromones to attract other roots.
- Plasmogamy occurs (2 cytoplasm combine, holding 2 nuclei) in the heterokaryotic stage. Gametangia is made needed for gamete production for new fungi.
- Karyogamy occurs, fusing nuclei into a zygote - then grows over years.
- Zygote creates a sporangia to germinate from mitosis and create a new mycelium network, until forming a sporophores from continuous budding. - Variation is created.
Reproduction - Fungi Heterokaryotic stage
When the one cytoplasm stores 2 genetically different nuclei.
Reproduction - Protists Definition & Reproduction
Eukaryotic living in moist environments. ‘Biological junk drawer of cells that don’t make tissue.
Can complete Binary fission too.
Multiple Fission (in unfavourable conditions)
1. Parent creates a cyst
2. Nucleus divides numerous times, producing multiple daughter cells.
3. Each daughter gains equal cytoplasm then wrapped in membrane.
4. Disperse from cyst when safe.
Reproduction - When do protists develop sexually?
Only produces sexually when under stress. E.g. Paramecium will use conjugation to create micronuclei with another, making variation to adapt and survive.
