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.phototropism b.gravitropism c.thigmotropism d.hydrotropism

Set up the journal pages below: If you didn’t do it yesterday… Page: 64 Date: Title: Flower Structure Tape yesterday’s reading part onto this page! For today’s CORNELL notes… Page: 65 Date: 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 + ovary  Sticky 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, bright colors, tube-like flowers Moths: White petals, open at night Flies: Rank odor, flesh colored 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 roll ex. 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 plant amylase secreted maltose absorbed 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 Radicle This 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. WORKTOGETHERWORKTOGETHER