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BIOD 171 MODULE 5 VIEW AHEAD 2026
COMPREHENSIVE STUDY SET
◉ Reproductive success. Answer: The ability to produce fertile offspring that survive to reproductive maturity and produce offspring of their own. ◉ Biological fitness. Answer: the measure of an individual's reproductive success. It is calculated as the average contribution to the gene pool made by a certain genotype within a population and the relative likelihood that these alleles will be represented in future generation. ◉ Sexual reproduction. Answer: It involves the meeting of special sex cells called gametes. A fertilised egg (zygote) occurs from the haploid gametes when the chromosome number changes from haploid to diploid. ◉ Gametes. Answer: Carry genetic information from both parents, therefore the offspring with contain a mix of parental genes. ◉ Diploid. Answer: (two complete sets) ◉ Haploid. Answer: (single set)
◉ Diploid and haploid cells. Answer: Refer to the number of sets of chromosomes within any cell - haploid (n) gamete from each parent combines to produce genetically unique diploid (2n) offspring. ◉ Somatic cells. Answer: A term used to describe all body/non- reproductive cells. ◉ Sexual reproduction in animals. Answer: The union of male and female gametes (sperm and ova) can occur outside the body (known as external) or inside the body (known as internal). ◉ Hermaphrodites. Answer: When the animal has both male and female reproductive organs. ◉ Internal fertilisation. Answer: Takes place inside the body of the female and involves mate attraction and compilation, which requires energy investment and put the organisms at risk of predation, but fewer eggs need to be produced. It occurs in some invertebrate and most vertebrates. ◉ External fertilisation. Answer: Occurs in aquatic or moist terrestrial environments, to prevent dehydration of gametes, gametes must be produced in large numbers to ensure success. It occurs in most invertebrates and some vertebrates.
◉ Stigma (female - flower). Answer: The sticky top surface of the flower in which pollen adhere too. ◉ Style (female - flower). Answer: Joins the stigma to the ovary. ◉ Ovary (female - flower). Answer: Where ovules is formed. ◉ Pollination. Answer: The process of gamete transfer from the male gametes in the pollen to the female part of the flower, stigma from the anthers. Once the pollen has been deposited on the stigma, a pollen tube germinates and grows down the style, carrying inside it the male gamete to and ovule contained in the ovary. ◉ Cross-pollination. Answer: The transfer of pollen from the anther of a flower of one plant to the stigma of the flower of another plant of the same species. It relies on outside agents to transfer pollen from anthers to stigma (wind or water). ◉ Self-pollination. Answer: The pollination of a flower by pollen from the same flower or from another flower on the same plant. Self-pollination requires less energy. ◉ Pollination by wind. Answer: The process of the transfer of pollen from one individual plant to another, whereby the pollen is carried by air currents (anemophily)
◉ Pollination by animal. Answer: Involves the animal going from plant to plant, pollen grains stick to them and are deposited into the next flower. Animals can also help plant reproduction by dispersing seeds around in different areas. ◉ Seed dispersal. Answer: The movement or transport of seeds away from the parent plant. The success of seed dispersal depends on the type of agent that the plant relies on. ◉ Germination. Answer: The process by which an organism grows from a seed or similar structure. ◉ Artificial pollination (plants). Answer: The process by which pollen from a selected plant with desirable traits is artificially transferred to the female stigma of another plant. ◉ Artificial pollination (plants) advantages. Answer: Used to pollinate many flowers (valuable in farming), a particularly useful and easy way of breeding new varieties of plants. ◉ Artificial pollination (plants) limitations. Answer: Cannot guarantee 'favourable' trait is passed on, reduced genetic variation; populations more susceptible to the environment.
- runners. Animals:
- budding: coral
- regeneration and fragmentation: flatworms, sea sponges
- pathogenesis: honey bees, aphids, ants, stick insects. ◉ Asexual reproduction advantages. Answer: Energy-efficient, required only one parent, no courtship required. ◉ Asexual reproduction disadvantages. Answer: Low genetic diversity, more prone to environmental change, inhibits adaption. ◉ Sexual reproduction advantages. Answer: High genetic diversity, less prone to environmental change, facilitates adaptations. ◉ Sexual reproduction disadvantages. Answer: Energy costly, required two parents, courtship is time and resource communing. ◉ Internal fertilisation advantages. Answer: Fertilisation more likely to occur, embryo protected from predators, offspring more likely to survive.
◉ Internal fertilisation disadvantages. Answer: Higher energy requirement to find mate, less offspring produced, more energy required to raise and care for young. ◉ External fertilisation advantages. Answer: Little energy required to mate, larger numbers of offspring produced, offspring can be spread widely; less competition. ◉ External fertilisation disadvantages. Answer: Many gametes go unfertilised, offspring often not protected by parent; may die. ◉ Bacteria (asexual reproduction). Answer: Unicellular prokaryotic microorganisms produce asexually; binary fission. ◉ Binary fission in bacteria: the steps. Answer: First cells elongate by building more cell wall, then the bacterial genome replicates and remains attached to the membrane. At the same time, any plasmids (small circular DNA) present replicate. Afterwards, they duplicated DNA begins to separate, moving towards the poles as the cell elongates and then cleavage furrow begins to form and cell wall form in cleavage furrow. Two identical daughter cells are produced. ◉ Ways bacteria incorporates variation into genome. Answer: Conjugation, transformation, transduction.
Asexual reproductions methods: binary fission, multiple fission, budding. Sexually reproducing protists; syngamy and conjugation. ◉ Transgenesis. Answer: The process by which a gene is removed from one species and inserted into the genome of another species; it increases the genetic variation within a population. ◉ Transgenesis - advantages. Answer: Guaranteed to express desired traits, increased yield and nutritional value, reduce the use of harmful chemicals. ◉ Transgenesis - disadvantages. Answer: Offspring genetically identical - disease susceptibility, 'escape' of GMO into the wild population, trade issue with non-GMO countries, long term effects on human health are unknown. ◉ Transgenesis in animals. Answer: GM Atlantic salmon have two genes from other species into their genome; these genes allow for the GM Atlantic salmon to grow all year round and grow 11 times faster than the average one.
◉ Transgenesis in plants. Answer: Bacillus thuringiensis (Bt) is a bacteria species that produces a protein that is toxic to selective insect pests. This gene is isolated and inserted into cotton plants to produce a species called Bt cotton. The plant produces a 'natural' insecticide that kills pests as well as higher yield and reduction to use of harmful and expensive pesticides. ◉ Fertilisation. Answer: Fusion of haploid male and female gametes. ◉ Zygotes. Answer: Diploid cell resulting from the fusion of gametes. ◉ Morula. Answer: Early stages of cell division. ◉ Blastocyst. Answer: Inner cell mass will form the embryo, outer layer will form the placenta. ◉ Implantation. Answer: The attachment of the blastocyst to the wall of the uterus. ◉ Pregnancy. Answer: The state of carrying a developing embryo or fetus within the female body. ◉ Embryo. Answer: Developing human from fertilisation to the eight week point.
hormones that stimulate or inhibit other endocrine glands, regulating the release of their hormones. ◉ Sex hormones. Answer: The hormones that specifically affect the growth and functioning of the reproductive organs or development of secondary sex characteristics. They are produced in special tissue in the ovaries and testes and in the pituitary gland and adrenal cortex. ◉ Gonads. Answer: The are reproductive organs that become functional at puberty and the reproductive cycle commences. Gametes are produced in male and female gonads by a process known as gametogenesis. ◉ Continuous breeding. Answer: Females fertility occurs in a cycle that is repeated all throughout the year and the animals are sexually activity all year round. ◉ Hormonal involved in mammalian reproduction. Answer: Androgens, oestrogen, progestogen. ◉ Seasonal breeding. Answer: Occurs only during periods of female fertility, commonly referred to as the animal being 'on heat' or 'in seasons' with the biological term being 'in oestrus'.
◉ Androgens (male hormones).. Answer: It controls the development and functioning of male sex organs and secondary sex characteristics. ◉ Oestrogen (female hormone).. Answer: The group control the development and functioning of the female reproductive system and secondary sex characteristics. ◉ Progesterone (female hormone).. Answer: The most common progestogen and it plays a primary role in pregnancy. It also stimulates the secretion of milk in mammary glands and a drop in its levels plays a role in initiating menstruation. ◉ Progesterone and oestrogen. Answer: They are produced by the ovaries and controlled by hormones of the pituitary regulate the ovarian cycle, menstrual cycle, maintenance of pregnancy, preparation for and maintenance of lactation and the pituitary secretes two gonadotropic hormones: follicle stimulating hormone (FSH) and luteinising hormone (LH). ◉ Follicle stimulating hormone (FSH). Answer: Secreted by the ovaries it initiates the ripping of the graffian follicle and ovum in the ovary and stimulates secretion of estrogen. ◉ Luteinising hormone (LH). Answer: Secreted in the pituitary gland it cause the follicle to release the ripe ovum (ovulation). Cause the
◉ Embryo transfer. Answer: Invivo fertilisation occurs (allowing for offspring to have both desired genes). It involves the female taking hormone injections to produce multiple ovum, the sperm being injected into the female for fertilisation to occur. The embryos are then flushed, and the best are then implanted into a surget animal - known as IVF. ◉ Selective breeding. Answer: Occurs in both plants and animals and involves picking the best traits for organisms to then insemination artificial to produce offspring Hydrate - the product of intense selective breeding. Hybrids vigour - show qualities superior to those of both parents. ◉ Monoculture. Answer: A large area of genetically identical crops. ◉ Cloning. Answer: The result of any asexual reproduction, were the offspring is identical to its parent. Plants do this through tissue scraping and mammals (animals and humans) do this through stem cells (somatic cell transfer). ◉ Cloning (plants) advantages. Answer: All plants have the same advantageous features as the original plant, value is consistent, ripen at the same time, quality is consistent, genetic modification is easily replicated.
◉ Cloning (plants) disadvantages. Answer: All are equally susceptible to the same diseases, all susceptible to the same pests, can strip the soil of nutrients, genetic diversity of the species is reduced. ◉ Cloning (animals) advantages. Answer: Animals with the best traits can be replicated, the general quality of heards can be more rapidly improved, genetically modified animals can be replicated so no specialised genes are lost. ◉ Cloning (animals) disadvantages. Answer: Genetic diversity decrease, cloned animals will all be equally susceptible to the same disease/parasites, hybrids vigour may be lost. ◉ Reproductive technologies. Answer: Range from those that manipulate fertilisation like artificial insemination, IVF, artificial pollination to those that split up embryonic stem cells and involve embryo implantation like embryo splitting and cloning. ◉ Cell cycle. Answer: G1 phase, S phase (synthesis), G2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis).
◉ Telophase (mitosis). Answer: The spindle disappears. New nuclear membranes form around two sets of chromosomes. ◉ Meiosis. Answer: Cell division that produces four daughter cells that are genetically different to parent cells and can only occurs in sex organs with sex cells (gametes). Stages of meiosis include: prophase I, metaphase I, anaphase I, telophase I, prophase II, metaphase II, anaphase II and cytokinesis. It ensures genetic variation within a species is maintained; this is central to a species surviving changes to the environment. ◉ Interphase (meiosis). Answer: Cell growth where chromosomes are replicating to form identical sister chromatids joined at the centrosome. ◉ Prophase I / Prophase II (meiosis). Answer: Chromosomes condense, and four chromatids form (two of each). Crossing over may occur and the nuclear membrane disappears. Centrosome move and spindles forms from microtubules. ◉ Metaphase I / Metaphase II (meiosis). Answer: Homologous pairs from in tetrads line at the equator with one chromatid of each pair facing each pole.
◉ Anaphase I / Anaphase II (meiosis). Answer: The chromosomes move to opposite poles, being pulled by spindle fibers as microtubules contract. ◉ Cytokinesis. Answer: It is the final step in cell division; it is the division of the cytoplasm and begins while the nucleus is completing its division. It separates the newly formed daughter nuclei and ensured that each cell has only one nucleus. ◉ Gene. Answer: A unit of DNA that is usually located on a chromosome and that controls the development of one or more traits and is the basic unit by which genetic information is passed from parent to offspring. gene. ◉ Allele. Answer: Are different versions of the same gene; originated as a result of a mutation. ◉ Meiosis - crossing over. Answer: The exchange of alleles between homologous chromosomes, resulting in a mixture of parental characteristics in offspring. Occurs in prophase I. ◉ Telophase I / Telophase II (meiosis). Answer: The chromosomes reach poles and spindle disappears. The nuclei forms and the chromosomes condense. Cytokinesis occurs and four daughter cells form, all genetically different.
