bell work (buff binder): copy the question below and write your entire answer. when a seed falls on...

BELL WORK (Buff Binder):Copy the question below and write your

entire answer.

When a seed falls on its side, the roots still grow downward. This is an example of –

a. phototropismb. gravitropismc. thigmotropismd. hydrotropism

Set up the journal pages below:If you didn’t do it yesterday…

• Page: 64• Date: 2-17-15• Title: Flower

Structure• Tape yesterday’s

reading part onto this page!

For today’s CORNELL notes…

• Page: 65• Date: 2-18-15• Title: Plant

Reproduction• Essential Question:

How do plants reproduce?

Anticipation Guide:STAND UP if the statement is true; SIT

DOWN if the statement is false.

1. Some plants are single celled organisms.2. Plants are prokaryotic and animals are

eukaryotic.3. Plants are photosynthetic autotrophs.4. Plants have chitin in their cell walls.5. Pollination is a part of plant reproduction.

Plant Parts/Systems

• Reproductive: Flower (with male and female parts)

• Transport: vascular tissues in stem

• Nutrient & Support: Leaves + Stem + Roots

• Response: Hormones + Tropisms

All of these parts and systems work together to help a plant maintain homeostasis.

Plant Reproduction

Flowers: reproductive organs of some plants

Male Reproductive Structure:

Stamen = anther + filament

Meiosis occurs on the anther to produce pollen (sperm)

Filament = stalk that supports the anther

Female Reproductive Structure:Pistil = stigma + style

+ ovarySticky stigma =

receives pollen from the anther

Pollen grows a tube down through the style

Meiosis occurs in the ovary to produce ovules (eggs)

Pollination

The pollen grain contains the male gamete

So, this is what sexual

reproduction in plants looks

like...awkward

Pollination: transfer of pollen from the anther to the stigma

• This is an example of cross-pollination as the pollen travels from one flower to a different flower. This is desirable in plants as it promotes genetic variation.

Click to view the animation

How does pollen get to the stigma?

Wind: Dull, scentless flowers with reduced petals

Bees/Butterflies: Bright color, nectar, scent. They sip nectar, get pollen on coats, transfer pollen from flower to flower

Birds: Nectaries, brightcolors, tube-like flowers

Moths: White petals, open at night

Flies: Rank odor, fleshcolored petals

Self-pollination occurs when pollen falls from the anther onto the stigma of the same flower

• Self-pollination is not desirable as it reduces genetic variation

Flowers will prevent self-pollination by either having stigma above stamen

or having parts mature at different times

Seed and Fruit Development After fertilization,

the petals and sepals fall off flower

Ovary “ripens” into a fruit (hormones)

Ovule develops into a seed

Flower to Fruit

Seed Dispersal Mechanisms

Seed Dispersal Mechanisms-Allow plants to avoid competition with parent plant

Wind - Flight mechanisms, like parachutes, wings, etc. Ex. Dandelion, maples, birch

Animals - Fleshy fruits which animals eat, drop undigested seeds in feces or burrs which stick to animals’ coats

Gravity - Heavy nuts fall to ground and rollex. acorns

Reproduction without flowers

• Mosses, ferns, and related plants have swimming sperm. The leafy tips of mosses produce male and female sex cells. Male sex cells swim through water on the surface of the plant to reach and fertilize female cells. Fertilization produces a spore capsule, that scatters spores into the air.

What kind of environmental conditions would be required for reproduction in these plants?

What kinds of limits does external reproduction impose on these plants?

Germination

The seed coat surrounds and protects the embryo and keeps the contents of the seed from drying out.

Enzymes are used in seed germination

starch

embryo plantamylasesecreted

maltoseabsorbed

Water enters the seed and activates enzymes.

The enzymes break starch down into maltose and then glucose. The glucose is used in respiration to provide energy for growth

Plumule

RadicleThis is the first part to grow out of the seed as it needs to absorb

more water

Debrief/Summary:

• Explain how gravitropism and a plant’s reproductive system work together.

WORK

TOGETHER