Biology HSC Past Paper PDF

Module 5 - Heredity Inquiry Question 1/5: How does reproduction ensure the continuity of a species? hhh Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but n...

Module 5 - Heredity Inquiry Question 1/5: How does reproduction ensure the continuity of a species? hhh Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: animals: advantages of external and internal fertilisation plants: asexual and sexual reproduction fungi: budding, spores bacteria: binary fission (ACSBL075) protists: binary fission, budding analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals (ACSBL075) evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture (ACSBL074) Sexual and Asexual Reproduction 18/10 Syllabus dot point Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: animals: advantages of external and internal fertilisation plants: asexual and sexual reproduction fungi: budding, spores bacteria: binary fission (ACSBL075) protists: binary fission, budding analyse the features of fertilisation, implantation and hormonal control of  pregnancy and birth in mammals (ACSBL075) evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture (ACSBL074) Sexual production: - Two parents - egg (mothers DNA) and sperm (fathers DNA) (cell gametes) - Create a new set of DNA - New unique cell (zygote) - Fertilisation - Plants: have both male and female parts (bisexual) - Advantage: provides genetic variation, populations are more likely to survive in changing environments. Advantages Disadvantages Fertilisation is less risky and the young are more likely to survive Slower reproductive rate - fewer offspring are produced over a Unfavourable genetic variation is eliminated from the population long time period more efficiently Mates have to be found and accepted as suitable. Finding and Generates genetic variation through recombination during meiosis competing for a mate can be risky and energetically costly and selects for beneficial genetic variation more efficiently Potential for spread of sexually transmitted diseases throughout Populations are better able to adapt to and survive changing population environmental conditions Energetically costly; gamete production, mating, gestation and Improves long term evolutionary potential of populations. rearing young requires a lot of ongoing energy input from the parent Asexual reproduction: - Clone of one parent - DNA identical to the parents DNA - Runners: the plant horizontal stem grows along the soil and new plants sprout from it and can live independently - Tubers: they grow on the actual plant, the sprout u - Bulbs: food storage, separate genetically identical plants - Cuttings: cutting off a small section of the plant  - Micropropagation: method of plant propagation using extremely small pieces of plant tissue taken from a carefully chosen and prepared mother plant, and growing these under laboratory conditions to produce new plants. - Binary fusion: separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA. - Starfish can lose a part of its body, that part that is detached from the body can regrow into a new starfish with identical DNA, and the star fish will re-grow the missing part. - Advantage: time efficient, requires less energy, no mate required, populations can grow likely and survive if the environments is stable Advantages Disadvantages Efficient form of reproduction rapid population growth can lead to overcrowding and increased amount of time and energy to produce offspring is minimal competition for resources population sizes can increase rapidly in optimal environments the lack of genetic variation in a population can cause death of the there is no need to find a sexual partner entire population if conditions change (e.g. a disease pathogen offspring are genetically identical to the stable environment arrives or a severe drought) because they are not adaptable to new environmental conditions (a) Define the term reproduction: the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents (b) Define the term sexual reproduction: the production of new organisms by the combination of genetic information of two individuals of different sexes. (c) Define the term asexual reproduction: generates offspring that are genetically identical to a single parent. (d) Tabulate the advantages and disadvantages of sexual reproduction (e) Tabulate the advantages and disadvantages of asexual reproduction Basis for comparison Asexual reproduction Sexual reproduction Meaning The process when living organisms give birth to their The process when living organisms give birth to their offspring, without the contribution of the other organisms offspring, with the input of another organism of the same of the same category. category and opposite gender. Types Binary fission, fragmentation, spore formation, budding Internal & External Fertilisation Number of organisms involved One (uniparental). Two (biparental - female & male) Cell division Mitotic division only Mitosis and Meiosis Involvement of sex cells Somatic cells of parents Germ cells of parents Occur in Some plants, very few animals (e.g. starfish), bacteria, fungi, Higher plants & animals protists Gametes No formation or fusion of gametes Gametes are always formed and fusion also occurs Reproduction notes.pdf Animal reproduction - Sexual Reproduction: Internal & External Fertilisation 21/10 Syllabus dot point Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: animals: advantages of external and internal fertilisation plants: asexual and sexual reproduction fungi: budding, spores bacteria: binary fission (ACSBL075) protists: binary fission, budding analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals (ACSBL075) evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture (ACSBL074) Fertilisation ★ Fertilisation is the fusion of male and female gametes to form a zygote.  ○ It can restore the original chromosome number of an organism ○ ★ Gamete cells are haploid ○ Haploid: only contain one set of chromosomes ★ When two gametes fuse they form a fertilised egg called a zygote which are diploid ○ Diploid: contains two sets of chromosomes ★ Fertilisation maintains the diploid chromosome number of a species. The contact of the sperm with the egg also triggers the start of the development of the embryo. External Fertilisation ★ Outside the animal body ★ Usually in water, provides a moist environment as well as providing a method of travel and dispersal ★ Animals release their gametes into the water and hope that the two gametes meet e.g. coral and most fish ★ Some animals have developed behavioural adaptations to increase likelihood of gametes meeting  ○ lot of gametes are being released (millions) this increases there chance of fertilisation ○ E.g. Frogs: male (Smaller) attaches itself to the female(Larger) Internal Fertilisation: ★ The female's body creates the moist environment ★ Other animals develop inside the womb and gain nutrients through the placenta or are born in an early ★ Some animals seal the zygotes in a protective shell and allow them to develop outside the body ○ The egg has enough nutrients to support the embryo to development Examples: ★ Salmon: ○ External fertilisation: live in the water ○ Come back to the shallow water of the river instead of the ocean as their is less disturbance and less area for eggs and sperm to drift away The shallow river is a safer environment to raise the babies, less predators They have to swim against the stream 4 year cycle ○ As the climate warms and the river temperature increases, the water raises which affects their fertilisation Oxygen solubility when the temperature is too high less oxygen dissolves in the water, slamons can not survive in these conditions. ★ Birds: ○ Internal fertilisation ○ The male impress the female as they know they are more valuable Males normally have brighter feathers to impress the female Females carry the egg and look after it when she gives birth (more responsibility) The only thing they do is give the sperm ○ Multiple male birds do a mating dance together to try and impress the female Through this dance the female decides who she wants to mate with  Advantage and disadvantage Advantage Disadvantage External ★ Large Number of Offspring: Since external fertilisation often ★ Lower Survival Rates: Many gametes and resulting embryos Fertilisation occurs in aquatic environments, many gametes can be do not survive due to predation, environmental hazards, or released, leading to a greater chance of fertilisation and a competition. higher number of offspring. ★ Dependent on Water: External fertilisation typically occurs in ★ Genetic Diversity: The mixing of gametes from multiple water, making the species dependent on a suitable aquatic individuals increases genetic variation, which can be environment. ★ Less Energy Investment by Parents: In many cases, external ★ Lack of Parental Protection: Offspring are often left fertilisation does not require significant post-fertilization vulnerable in the external environment, leading to higher parental care, allowing parents to focus on producing more mortality rates. offspring. Internal ★ Higher Survival Rates of Offspring: Since fertilisation occurs ★ Energy Investment in Offspring: Parents, especially females, Fertilisation inside the body, the developing embryo is better protected often invest more energy in the care and protection of fewer from external threats. offspring, including gestation and sometimes postnatal care. ★ Less Gamete Waste: Fewer gametes are required compared ★ Complex Mating Behaviours and Systems: Internal to external fertilisation, as the process is more controlled and fertilisation requires complex reproductive systems and ensures that sperm reaches the egg. behaviours, which can be energetically costly and more ★ Ability to Reproduce in Diverse Environments: Species using vulnerable to reproductive failures. internal fertilisation are not as dependent on water for ★ Lower Genetic Diversity: Internal fertilisation often involves reproduction, allowing them to inhabit various ecosystems. fewer mating partners, potentially leading to reduced genetic variation compared to external fertilisation. Plant reproduction Sexual and Asexual 22/10 Syllabus dot point Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: animals: advantages of external and internal fertilisation  plants: asexual and sexual reproduction fungi: budding, spores bacteria: binary fission (ACSBL075) protists: binary fission, budding analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals (ACSBL075) evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture (ACSBL074) Asexual - Natural Plant Propagation Vegetative propagation ★ Parts of the parent plant can be detached and will grow into a new individual ○ Less time and energy, they grow immediately ○ It reduces the need for pollinators and pollination, removing the need for fertilisation, production of seeds and seed dispersal ○ Lack of genetic diversity (copy and paste) Tubers: ★ Description: Tubers are enlarged parts of an underground stem that store nutrients for the plant. They contain "eyes" or buds that can sprout and form new plants. ★ Examples: ○ Potato (Solanum tuberosum): Potatoes have eyes that sprout and grow into new plants. ○ Yam (Dioscorea spp.): Similar to potatoes, yams grow from tuberous roots. Rhizomes: ★ Description: Rhizomes are horizontal, underground stems that grow new shoots and roots at intervals. They allow plants to spread over a wide area. ★ Examples: ○ Ginger (Zingiber officinale): The thick underground rhizome is harvested for spice, but it can also sprout new plants.  ○ Bamboo (Bambusoideae): Bamboos spread aggressively through their rhizomes, which can give rise to new shoots. Bulbs: ★ Description: Bulbs are underground storage structures that contain a short stem surrounded by fleshy leaves or leaf bases. The bulb stores nutrients to support new growth. ★ Examples: ○ Onion (Allium cepa): Onions grow from bulbs, and each bulb can sprout and grow into a new plant. ○ Tulip (Tulipa spp.): Tulip bulbs are planted to produce colorful flowers each spring. Runners (Stolons): ★ Description: Runners, also known as stolons, are long, thin stems that grow horizontally along the ground. New plants grow at nodes where the runner touches the soil. ★ Examples: ○ Strawberry (Fragaria × ananassa): Strawberries produce runners that root and form new plants. ○ Spider plant (Chlorophytum comosum): Spider plants produce plantlets on runners that can be potted to grow new plants. Plantlets: ★ Description: These are small plants that develop on the edges of a mature plant’s leaves or stems. They can drop off and grow independently once they establish roots. ★ Examples: ○ Kalanchoe (Kalanchoe daigremontiana): The "Mother of Thousands" plant grows tiny plantlets along its leaf edges. ○ Spider plant (Chlorophytum comosum): Also produces plantlets at the ends of runners. Asexual - Artificial Plant Propagation Cuttings: ★ Description: Cuttings involve taking a piece of a plant—typically a stem, leaf, or root—and planting it in soil or water to encourage it to grow into a new plant. Rooting hormone is sometimes used to aid in root development. ★ Examples: ○ Rose (Rosa spp.): Stem cuttings from a mature rose can be planted to grow a new rose bush. ○ Coleus (Plectranthus scutellarioides): Coleus cuttings are easily rooted in water and grow quickly into new plants. Grafting: ★ Description: Grafting is a technique in which the tissue of one plant (scion) is joined to the tissue of another plant (rootstock). The two plants grow together, combining the best traits of each (such as disease resistance or better fruit quality). ★ Examples: ○ Apple trees (Malus domestica): Grafting is commonly used to combine disease-resistant rootstock with a scion that produces desirable apple varieties. ○ Roses (Rosa spp.): Rose bushes are often grafted to create stronger, more resilient plants that produce high-quality flowers. Plant reproduction Sexual and Asexual 24/10 Syllabus dot point Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: animals: advantages of external and internal fertilisation  plants: asexual and sexual reproduction fungi: budding, spores bacteria: binary fission (ACSBL075) protists: binary fission, budding analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals (ACSBL075) evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture (ACSBL074) sexual reproduction in plants fuse school Flower Structure ★ Angiosperms have flowers ★ Flowers = reproductive structures ★ Most flowers contain both male and female reproductive organs → and are known as bisexual. In some species, the flowers are unisexual with the male and female organs in separate flowers on the same plant. ★ Other flowers can contain only one part ★ Native Australian plants often only have the carpel and stamen due to dry weather conditions (no petals etc. eg- red bottle brush, grevillea)  ★ Fruit develops from the ovary of a plant Parts of a flower: ★ Female Part: ○ Pistil is made of three major parts Stigma: pollen is supposed to stick on to this sticky structure Style: the stalk that supports the stigma Ovary: where fertilisation occurs, seeds are formed within it and well ripen into a fruit ★ Male part: ○ Anther is a fluffy structure that produces pollen ○ Filament is a stalk that supports the anther. ★ Other parts: ○ Sepals: protect a developing flower bud ○ Petals: attract pollinators Red colours attract birds, white attracts moths as they are nocturnal and white is the most attractive with night vision. Recessive: relating to or denoting heritable characteristics controlled by genes which are expressed in offspring only when inherited from both parents. Fertilisation in Angiosperms ★ Development of seed which grow into new baby plants ★ They are double fertilisation ★ Mature Pollen grains, consist of two types of cells: ○ Tube cells: the pollen uses this cell to burrow down the pollen tube from the stigma through the style to the inside area of the ovary ○ Generative cell: divide into two sperm cells, they target an ovule One of the sperms cells fertilise an egg which will form a zygote (diploid cell) The other sperm cell joins with the two polar nuclei which will develop into endosperm (triploid cell) Full of nutrients for a developing baby plant  ★ The surrounding ovary will ripen and develop into a fruit (not necessarily an edible fruit) ○ This helps the seed travel far from the parent plant ○ Non edible fruit can, stick to animals fur or be carried by wind or water ○ Edible fruits can be eaten which the seeds then pass through the digestive system unharmed and poo is out. Pollination ★ Pollen: ○ Contains amino acids that some pollinators feed on E.g. bees use it as a food source for their young ★ Haploid male pollen is transferred from the anther to the stigma of the same or different flower. ★ TYPES: ○ Self-Pollination The transfer of pollen grains from the anther to the stigma in the same flower E.g. Nectar attracts the bees to the flower and while they are drinking the nectar pollen tends to stick on to the legs of the bees which is then brushed on to the stigma, this means the flower is pollinated Produces similar offspring with little variation Similar to sibling marriage 😥 They do not need to expend energy to attract external factors for pollination Eg. Dandelion ○ Cross-Pollination The transfer of pollen grains from the anther of a flower on one plant to the stigma of another plant of the same species’ Plants of this method rely completely on insects and external factors for pollination  Wind Pollination (Type of Cross Pollination) Insect Pollination (Type of Cross Pollination) Bird Pollination (Type of Cross Pollination) ○ Birds are enticed to a plant/flower by colour. Pollen sticks to birds, and is transferred to another flower. Eg. Wattle birds and waratahs Mammal Pollination (Type of Cross Pollination) ○ Pollen sticks to animals Eg. Pygmy possum and banksia ★ Additionally - Animals assist in dispersing the seeds and fruits of pollinated plants. ★ Agents of Pollination/ Pollination Agents - Pollinating agents can be animals such as insects, birds, and bats; water; wind; and even plants themselves, Fruit Production, Seed dispersal & Germination ★ Once the ovule/s(eggs) in the ovary are fertilised. The ovary grows into a fruit/s as the sepals and petals fall away. The fertilised ovules form the seeds of the fruit/s containing the diploid genetic material of the plant. ★ The fruit is a specialised structure that protects the seed and may enhance seed dispersal. The fruits have adaptations which can determine how the seed gets dispersed and may have large stores of nutrients to support the seed. ★ If these seeds are successfully dispersed it can then germinate, germination occurs when the seed receives nutrients to grow into a new plant. Asexual Reproduction In Fungi, Bacteria and Protists 25/10 Syllabus dot point Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to: animals: advantages of external and internal fertilisation plants: asexual and sexual reproduction fungi: budding, spores bacteria: binary fission (ACSBL075) protists: binary fission, budding analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals (ACSBL075) evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture (ACSBL074) Asexual Reproduction Table Revised Binary fission ★ Splitting into two, most common in single celled organisms  ○ The organism grows to its maximum size. ○ The nucleus them reproduces to form two complete and identical daughter nuclei ○ The cytoplasm is divided and the parent cell splits identical daughter cells ★ Protists: ○ Occurs when a single protist divides its nucleus and then divides itself into two separate organisms. ★ Bacteria: ○ They do not have a proper nucleus, just a single thread of nuclear material ○ This is reproduced as in other organism so that each daughter cell gets a copy ○ Under ideal conditions, they can reproduce every 20 min to form a huge number of offsprings Amoeba (type of protist) - single celled animal Bacteria Budding ★ It occurs in yeast which is a type of fungus consisting of single cells. ★ A bulge called a bud forms on the yeast cell. ○ The nucleus divides and a daughter nucleus goes into the bud ○ It grows bigger until eventually forming a daughter cell ○ If growth conditions are good the small bud my eventually form on the larger ones before they break off Chains of yeast cells are formed. ★ A type of budding also occurs in a Hydra ○ In a multicellular organism such as a hydra it is the undifferentiated cells which are able to form into buds. Yeast Hydra Spores ★ Spores are tiny, single cells used by some plants, fungi, and algae for reproduction. ★ They contain all the genetic information needed to grow into a new organism. ○ Spores are released into the environment, often by wind or water. ○ If a spore lands in the right conditions (like moisture and warmth), it can grow into a new plant or fungus. ○ This type of reproduction doesn't require fertilisation or pollination. Dissection of a flowers 31/10