Week 2 Flashcards
Types of Asexual Reproduction
- Binary fission
- Fragmentation
- Budding
- Parthenogenesis
- Sporulation
Binary Fission
- parent cell splits into two identical
daughter cells of the same size. - Some unicellular eukaryotic
organisms undergo binary fission by
mitosis - Examples, Amoeba, Euglena, and
Paramecium
Fragmentation
- a parent organism breaks into fragments, or
pieces, and develops into a new organism. E.g., Starfish
-There is a noticeable difference in the
size of the individuals, whereas in
fission, individuals of approximately the
the same size are formed
Budding
a parent cell forms a bubble-like bud. The bud stays attached to the parent cell while it grows and develops. When the bud is fully developed, it breaks away from the parent cell and forms a new organism. E.g.,
Hydra, corals, Yeast
Partheonogenesis
offspring develops from the egg or female gamete without prior fertilization
from the male gamete. Occurs in invertebrates such as flees and wasps. May be facultative or obligate.
* A facultative parthenogenesis is one in which the female reproduce either
sexually or asexually. E.g., Mayflies
* Obligate parthenogenesis is one in which the organism reproduce only by
asexual means. E.g., some species of lizards
Sporulation
Sporulation is the act or process of forming spores; spore formation.
* Spores are the reproductive elements of organisms, such as protozoa, fungi,
and cryptogamic plants. Cryptogamic plants are plants that reproduces by
spores, without flowers or seeds
Vegetative propagation
A method of plant breeding/reproduction not through pollination or
via seeds or spores but by way of separating new plant individuals that
emerge from vegetative parts, such as specialized stems, leaves and roots
and allow them to take root and grow.
* Vegetative organs are the non-reproductive parts of the plant which may
include roots, stems, and leaves.
Bulb
A modified stem that is the resting stage of certain seed plants,
particularly perennial monocotyledons.
* Most of the bulb consists of thick, fleshy, modified leaves. Some
bulbs have outer modified leaves, which are dry and paper thin,
while others do not.
* Bulbs contain food reserves to enable the plant to survive adverse
conditions.
E.g., Onions, garlic, lilies
Corms
Are enlarged bulb-like underground stems. They store nutrients in fleshy, solid stem tissue externally surrounded by papery leaves.
corms contain
solid tissue internally and bulbs have only layers of leaves.
* Corms produce adventitious roots and possess buds that develop into
new plant shoots.
Examples are crocus and taro
Tuberous Roots and Shoots
- A root is a thickened underground structure
containing stored food the main, descending root of a plant has a single, dominant main stem. E.g., carrots and beets - A tuberous shoot is an enlarged stem
tissue. E.g., Sweet potato
Stolon/Runners
- Stolons are horizontal stems which grow at
the soil surface or just below surface of the
soil. They form new plants at the ends or at
the nodes. - Originate from existing stems
E.g., Strawberry plants, mint plants and some
types of grasses
Rhizome
- Rhizomes are horizontal
underground plant stem capable of
producing the shoot and root systems of a
new plant. - rhizomes are the actual stem modified
whereas stolons originate from existing
stems. - Rhizomes are used to
store starches and proteins and enable plants
to perennate (survive an annual unfavourable
season) underground.
E.g., ginger, turmeric
Sucker
A shoot from the roots or lower part of the stem of a plant; so called,
perhaps, from diverting nourishment from the body of the plant.
E.g., Banana plants
