Term
Every structure and process of plants exists to
maximize the chance that the individual will
produce offspring. |
|
Definition
• flower = reproductive structure that:
– produces gametes
– attracts gametes from other individuals
– nourishes embryos
– develops seeds and fruits |
|
|
Term
|
Definition
male gametes; contribute genetic information
(DNA), but few or no nutrients to the offspring |
|
|
Term
|
Definition
| nuclear division that halves the chromosome number |
|
|
Term
|
Definition
fusion of gametes (haploid cells) that produces a
zygote (diploid cell) |
|
|
Term
|
Definition
female gametes; contribute both DNA and a
store of nutrients to the offspring |
|
|
Term
| self-fertilization (selfing): |
|
Definition
occurs when sperm and
egg from same individual combine to produce
offspring
– PRO: virtually assures successful pollination
– CON: less genetic diversity |
|
|
Term
|
Definition
Occurs when sperm and egg from
different individuals combine
– PRO: more genetic diversity
– CON: riskier in terms of the chances of pollination occurring |
|
|
Term
| meiosis occurs in sporophytes; results in the production of |
|
Definition
|
|
Term
| The Land Plant Life Cycle (7) |
|
Definition
• meiosis occurs in sporophytes; results in the production of haploid spores
• spores produce an adult without fusing with another cell
• meiosis and spore production occur inside sporangia
• spores divide by mitosis to form multicellular, haploid gametophytes
• gametophytes produce gametes by mitosis
• fertilization occurs when two gametes fuse to form a diploid zygote
• zygote then grows by mitosis to form the sporophyte |
|
|
Term
|
Definition
• does NOT involve fertilization
• results in the production of clones genetically
identical copies of the parent plant
• all asexual reproduction is based on mitosis, but a
wide array of mechanisms are involved
• advantage: it is very efficient
• disadvantage: genetically similar populations are
more likely to succumb to diseases
|
|
|
Term
| • Flower formation begins when |
|
Definition
an apical meristem
stops making energy-harvesting stems and
leaves, and becomes a floral meristem able to
produce the modified leaves that make up flowers. |
|
|
Term
| • Flowering can be stimulated by |
|
Definition
external cues,
internal cues, or both. |
|
|
Term
| external environmental cues: |
|
Definition
– length of day and night
– the arrival of seasonal rains
– other mechanisms |
|
|
Term
|
Definition
– favorable nutritional status
– hormones |
|
|
Term
| Most flowers have four basic organs: |
|
Definition
1. sepals
2. petals
3. stamens
4. carpels (one or more)
• four organs are attached to a compressed portion of
stem called the receptacle
• all four organs are not necessarily present in all flowers |
|
|
Term
|
Definition
leaf-like structures that make up the
outermost part of the flower
– green
– photosynthetic
– arranged in a circle or whorl attached to the receptacle
– enclose the flower bud as it develops and grows
|
|
|
Term
|
Definition
arranged around the receptacle in a whorl
– often brightly colored
– advertise the flower to pollinators |
|
|
Term
|
Definition
reproductive structures that produce male
gametophytes (pollen grains), which in turn produce
sperm
– filament: stalk
– anthers: pollen-producing organs
|
|
|
Term
|
Definition
produces the female gametophytes, which
produce eggs
– stigma: the moist tip that receives pollen
– style: stalk
– ovary: at the base of the carpel |
|
|
Term
|
Definition
contain both stamens and
carpels |
|
|
Term
| imperfect flowers flowers: |
|
Definition
contain either stamens or
carpels |
|
|
Term
| monoecious (“one house”): |
|
Definition
have separate
stamen- and carpel-producing flowers on the
same individual |
|
|
Term
| dioecious (“two houses”): |
|
Definition
have either stamenor
carpel-producing flowers, but not both on the
same individual |
|
|
