Reproduction Flashcards
what is reproduction? types?
the production of individuals of the same species i.e. the next generation of species.
2 basic types of reproduction.
Asexual reproduction means simple cell division that produces an exact duplicate of an organism. There are many types of asexual reproduction.
What is binary fission & where does it occur?
division into two
It is the simplest & most common method of asexual reproduction. It occurs in prokaryotes (bacteria), many unicellular eukaryotes e.g. protozoa & some invertebrates
How does binary fission occur in bacteria?
the DNA is duplicated & two copies of DNA are formed. The two copies move towards the opposite poles of cell.
The cell membrane invaginates in centre & divides the cytoplasm into two.
New cell wall is deposited between two cross membranes. It results in the formation of two daughter bacteria.
How does binary fission occur in unicellular eukaryotes or protozoa? draw diagram
the nucleus of parent organism divides into two (by mitosis). It is followed by the division of cytoplasm. So 2 daughter cells of almost equal size are formed.
paramecium, amoeba
How does binary fission occur in invertebrates? common in?
body is cut into two halves (fission) & the missing body parts are regenerated in both halves.
This type of asexual reproduction is common in planaria & many echinoderms.
What is budding?
How does budding occur in yeast?
Which animals reproduce by budding?
- a type of asexual reproduction where a small outgrowth (bud) develops on the parent’s body, eventually growing into a new organism.
- Animals such as sponges, Hydra, & corals.
What happens to the yeast buds after they grow?
Describe the budding process in animals like Hydra.
- The buds may separate from the parent body, or they may remain attached, forming colonies.
- pg 62
What are sporangia in Rhizopus?
How are spores formed inside a sporangium? how do they look like?
How do spores develop into new Rhizopus?
- Sporangia are thick-walled spore sacs formed by the body cells of Rhizopus when it reaches reproductive age
- Inside a sporangium, a cell divides many times to form numerous daughter cells called spores.
- Under favorable conditions, the released spores germinate & develop into new Rhizopus organisms.
What is the function of the cyst?
What happens when sporangia mature?
What is the difference b/w bacterial spores & Rhizopus spores?
- The cyst is a thick wall that covers each spore, allowing it to survive unfavorable conditions.
- they burst open, releasing the spores.
- Bacterial spores, such as those formed by Clostridium & Bacillus species, are called endospores because they are formed inside bacterial cells, while Rhizopus spores are formed inside sporangia.
What is parthenogenesis?
How do queen honeybees use parthenogenesis?
what animals reproduce by means of parthenogenesis?
What happens to the fertilized eggs laid by the queen honeybee?
- a type of asexual reproduction where an unfertilized egg develops into a new organism.
- Queen honeybees lay unfertilized eggs that develop into haploid male bees (drones) through parthenogenesis.
- Some fishes, frogs and insects
- some eggs are fertilized by male bees & these develop into diploid females (new queen and worker bees).
what is vegetative propagation?
When vegetative parts of plants i.e. roots, stems or leaves give rise to new plants, the process is called vegetative reproduction/ propagation. It occurs naturally, & can also be brought about artificially.
asexual reproduction in plants
creeping stem types?
describe the first one? with examples?
runner and suckers
pg 64
name examples of suckers? what are they?
pg 64
underground stems? examples?
how does natural vegetative propagation happen in leaves? example?
pg 64
what is artificial vegetative propagation?
the growing of new plants from cut portions of the vegetaative plant body
stem cuttings? example? why leaves are removed? why cut stem must have at least 2 nodes close to end that is inserted into the ground?
pg 65
