Mod 5 HEREDITY: Reproduction Flashcards
Identify the two types of reproduction
Asexual reproduciton involves a single parent creating genetically identical copy of itself.
Sexual reproduction involves the contribution from two parents of their genetic material (contributed haploids) that fuse to form a diploid which is a genetically unique organism.
What are advantages and disadvantages of ASEXUAL reproduction?
+ Offspring is genetically identical which means they are suited for a stable environment
- Offspring is susceptible to any changes in the environment. It could result in extiction of species due to inability to adapt
+ Population size increases rapidly
- High number of an offspring within an area can lead to scarcity of resources and increase intraspecific competition
+ This form of reproduction requires low energy investment because there is no need to seek a partner and invest energy into mating rituals
- Genetically identical offspring will have lower chances to adapt to the environment meaning that the species have a decreased chances to survive
What are advantages and disadvantages of SEXUAL reproduction?
+ Increased genetic variation due to recombination of different alleles
- Recombination of alleles could lead to the introduction of harmful mutations
+ Increased genetic variation due to contribution of different DNA material from each parent
- Production of gametes and finding a partner is energy consuming
+ Species are capable of adapting to the changes in the environment, meaning that the offspring can exist in a wide range of environments
- Reproductive rate is slower with fewer offspring produced over a longer period of time
What is a bulb? Provide examples
An underground organ surrounded by fleshy leaves. It provides nutrients during the dormancy period.
E.g Onion, garlic
What is fragmentation?Provide examples
Broken pieces of a plant can grow independently from the parent organism and develop into a mature organism
E.g Fiddle leaf fig tree, bryophytes (mosses), green algae
What is a rhizome? Provide examples
Horizontal underground growing stem that produces new shoots and roots
E.g Ginger
What is a runner? Provide examples
A stem that runs away from the parent nearby the ground and gives rise to new shoots and roots
E.g strawberry, spider plant
What is a sucker? Provide examples
A sprout that grows away from the base of the plant
E.g Banana, apple tree
What is a tuber? Provide examples
An underground stem that is specialised to store starch and provide nutrients to the plant during dormancy
E.g potato
What are the four groups of a plant kingdom?
1) Bryophytes (mosses)
2) Pteridophytes (ferns)
3) Angiosperms (flowering plants)
4) Gymnosperms (cone bearing plants)
What does alternation of generations mean?
Reproductive stage in plants which involves the switching between the gametophyte phase and a sporophyte stage.
What is a sporophyte?
Asexual stage of a reproductive cycle that produces spores (haploid stage)
What is a gametophyte?
Sexual stage of a reproductive cycle that produces gametes (diploid stage)
What plants (refer to the 4 types of animal kingdom) are homosporous and heterosporous?
Homosoporous (same kind of spores) - bryophytes and pterydophytes.
Heterosporous (different kind of spores, treat it as female gamete and male gamete, they are different) - angiosperms and gymnosperms.
Find an image online “alternation of generation” and comment on the process. What is happening?
Gametophyte comes from spores that are produced by sporophytes in meiosis. Gametes produced by the gametophyte fuse together to create a zygote. Zygote then undergoes cell division and grows into a sporophyte which then produces spores to create a gametophyte. The cycle repeats itself again. This process is called alternation of generations where both multicellular phases of a plant alternate between each other.
Distinguish between pollination and fertilisation
Pollination is the process of pollen grains being transfered from an anther to a stigma. Whereas fertilisation invloves the fusion of a sperm which comes from the pollen grain and travels down the style with an egg.
Name female and male reproductive parts of an angiosperm and state their function.
PISTIL (female):
Stigma - sticky part on top of a style which catches pollen grains.
Style - a long passageway that connects stigmae with ovaries.
Ovaries - contains eggs that await sperm to be fertilised.
STAMEN (male):
Anther - produces pollen
Filament - supports anther by holding it up.
Recall all of the 4 types of asexual reproduction in animals.
Budding, fission, fragmentation, parthenogenesis.
Define budding + examples
A new organism develops from an outgrowth or bud due to cell division at a particular site
E.g Corals, hydras, yeast
Define fission + examples
A single parent organism splits itself into separate organisms.
E.g Planaria, sea anemone
Define fragmentation + examples
A body part detaches from a parent organism and develops into new organism, whereas the parent organism regenerates the lost body part
E.g Sea sponge, sea star, planaria
Define parthenogenesis + examples
An unfertilised egg develops into a complete individual.
E.g Honey bees, ants, komodo dragon, hammerhead shark
What are advantages and disadvantages of internal fertilisation?
+ Fertilisation is more likely to occur because gametes are positioned closely to another
- Fewer number of offspring is produces
+ Embryo is more likely to survive because it is protected by mother’s uterus
- Large investment in energy
What are advantages and disadvantages of external fertilisation?
+ Offspring produced is spread widely
- Many offspring die because of lack of parental care
+ Large number of offspring is produced
- Many eggs go unfertilised
+ Little investment in energy needed in mating ritulas
- More gametes must be produced to increase likelihood of successful fertilisation
What is hyphae and mycelium
Hyphae - a fillament of fungus that makes up mycellium. They are responsible for absobing nutrients.
Mycelium - a structure of a fungus that consists of hyphae.
Describe how fungi can reproduce asexually
There are three methods of asexual fungi reproduction. Fungi can reproduce via fragmentation by spliting mycelium into smaller pieces that give rise to new fungal colony. Second method involves budding which involves a development of an outgrowth from fungus which detaches as soon it matures. Lastly, haploid mycelium produces mitospores that further divide via mitosis and eventually develop into new mycelium after the period of germination.
Identify plasmogamy and karyogamy
Plasmogamy - a stage in sexual reproduction in fungi which involves the fusion of mycelium cytoplasm.
Karyogamy - the fusion of nuclei which forms a zygote.
Find a diagram on sexual reproduction on fungi and comment about the process.
Plasmogamy is the union of different fungi mycelium cytoplasm while the haploid nuclei do not mix. This process forms a dikaryon which is a cell that has 2 separate nuclei that haven’t been fused together yet. After the formation of dikaryon, the heterokaryotic mycelium forms a fruiting body.
Karyogamy is when two haploid nuclei are fused together to form a diploid zygote. This zygote then undergoes meiosis in order to produce haploid (n) cell that are developed into meiospores (spores produced during meiosis).
What are the three types of asexual reproduction in protists?
Budding, binary fission and multiple fission
Define the two types of sexual reproduction in protists.
Syngamy - complete and PERMANENT fusion of two haploid gametes to form a zygote Haploid + haploid = Diploid (fusion)
Conjugation - TEMPORARY fusion of two individuals haploid pronuclear to form a zygote. In each protist, the exchanged haploid pronuclei fuse to form a new genetically unique diploid zygote nucleus. This cell will then continue to reproduce asexually via binary fission.
