16.4 Reproductive Strategies Flashcards
What is Asexual Reproduction?
The reproductive process in which a parent organism produces genetically identical offspring
What does Sexual Reproduction involve?
The production of gametes by meiosis, followed by fertilization between genetically distinct parental gametes to produce genetically distinct offspring
Describe the chromosome of bacteria and other prokaryotes?
Bacteria and other Prokaryotes have a singular, circle chromosome and no nucleus
What form of cell division do Bacteria and other Prokaryotes undergo?
Binary Fission
What is the minimum amount of time that bacteria can divide in?
20 minutes
What is exponential growth?
The sequence of repeated growth in binary fission
What does exponential growth allow?
Bacteria to produce huge populations in a short amount of time
What is a downside to exponential growth?
Because the offspring are identical, if one is vulnerable to a toxin they all are vulnerable
What is another way that some bacteria are able to reproduce by?
A process called Conjugation
What is Conjugation?
The transfer of genetic material from one cell to another by cell-to-cell contact through a bridging structure called a pilus
How does Binary Fission occur?
The circular chromosome attaches itself to the cell wall. As the new chromosome replicates, the new chromosome attaches to the cell wall. The cell elongates and the formation of a septum then separates the two chromosomes
What does Binary Fission result in?
Two completely identical daughter cells
What does Conjugation create?
Cells with new genetic combinations
How does Conjugation work?
One bacterium transfers all or part of its genetic material to another bacterium. The receiving bacterium then undergoes binary fission
What are some Eukaryotes that are able to undergo Binary Fission?
Algae and Fungi
What can Conjugation only take place between?
Non-identical bacterial cells
What does Conjugation result in?
A single genetically unique daughter cell that can undergo binary fission to create a new colony of cells
What is Budding?
A form of Asexual reproduction in which a complete miniature version of the parent grows out from the parents body. The new organism then separates to become an independent organism
What is Vegetative reproduction?
A form of asexual reproduction where a plant extends thin creeping stems that then creates roots and disintegrates the connecting stem
What is Fragmentation?
A form of asexual reproduction that involves the creation of new plants from a fragment of the parent plant
What is Parthenogenesis?
A form of Asexual reproduction in which an unfertilized egg develops into an adult ex. in honey bees
What is different about spores?
It’s asexual reproduction does not require offspring to develop close to the parent
What is a spore?
A structure that contains genetic material and cytoplasm surrounded by a protective sheath or wall that protects it until conditions are favourable
What generations does the lifecycle of plants consist of?
The haploid generation and the Diploid generation. This is called alteration of generations
What is a sporophyte?
The diploid generation of a plant
How do Sporophytes create haploid spores?
By meiosis
What does each Haploid spore grow into?
A plant body known as a gametophyte (still haploid)
What do Gametophytes do?
Produce male and female gametes
What do the male and female gametes produced by the Gametophytes do?
Fuse and develop into a sporophyte
What is the dominant generation in vascular plants?
The diploid sporophyte
What is the dominant generation in non-vascular plants?
The haploid Gametophyte
What is the leafy green mat in mosses?
The gametophyte
What is the stalk that grows from the mosses?
The sporophyte
What are the Haploid gametophytes in conifers?
The microscopic structures within the male and female cones that are produced by the tree
Where is the female gametophyte produced in a cone?
The top of the female cone that produces female spores
Where is the male Gametophyte produced in conifers?
It is produced by a structure found on the male cone
What does the male cone release in conifers?
They release pollen that is dispersed by the wind tht fertilize female cones
What does the term alternation of generations refer to?
The alternation of Haploid and Diploid generations
What are the two distinct adult forms that characterizes animals that reproduce sexually and asexually?
Non-motile polyp and free swimming medusa
What are the 3 advantages to Sexual reproduction?
- Some offspring have greater ability to adapt to a changing environment and resist parasites or toxins
- Competition amongst siblings may be reduced if they are genetically diverse
- Pairing and the crossover of homologous chromosomes give opportunity to replace or repair damaged chromosomes
What are the advantages of Asexual reproduction?
- Asexual reproduction often happens quicker that sexual reproduction and does not require a second parent
- Asexual reproduction usually requires less energy than sexual reproduction
- Many forms of sexual reproduction help to maximize the chances that the offspring will survive by not separating until it is capable of independent survival
