1. 1 Explain Why is it adaptive for some seeds to remain dormant before they germinate Apply Concepts The seeds of a bishop pine germinate only after exposure to the extreme heat of a forest fire. Evaluate the significance of this structural adaptation 2 Pose a Question A new angiosperm species is discovered. What questions would you ask before predicting how its seeds are dispersed- explain why you would ask each.

2. Ch 24 Plant Reproduction and Response
24.2 Fruits and Seeds

3. Seed and Fruit Development
After fertilization, nutrients flow into the flower tissue and support the development of the growing embryo within the seed
Fruit
Mature angiosperm ovary, usually containing seeds
Fruit isn’t limited to “fruits” like apples but also includes rice, corn, etc…

4. Ovary wall surrounding a fruit may be fleshy, (grapes and tomatoes) or tough and dry (shell that surrounds peanuts).

5. Dispersal by Animals
Many seeds especially those in sweet, fleshy fruits are often eaten by animals
Seeds are covered with tough coatings, allowing them to pass through an animal’s digestive system unharmed
Seeds then sprout in the feces of the animal.

6. Dispersal by Animals Fruits provide nutrition for the animal
Help the plant disperse its seeds
Often to areas where there is less competition with the parent plants.

7. Dispersal by Animals
Dry fruits sometimes have burrs or hooks that catch in an animal’s fur.

8. Dispersal by Wind and Water
Typically contained in lightweight fruits that allow them to be carried in the air or in buoyant fruits that allow them to float on the surface of the water
Dandelion seed
Coconut.

9. Dormancy Germination Embryo is alive but not growing
Growth of plant embryo resumes.

10. How Seeds Germinate Seeds absorb water
Causes food-storing tissues to swell and crack open the seed coat
Young root emerges and begins to grow
Shoot then emerges.

11. The Role of Cotyledons First leaves
Store nutrients and transfers them to growing embryo as the seed germinates.

12. Monocots have one cotyledon
Stays underground to nourish young plant
Growing monocot shoot emerges from the soil protected by a sheath.

13. Dicot have two cotyledons
Lack protection of a sheath for plant tip
Upper end of the shoot bends to form a hook that forces its way through the soil
Protects tip of plant, which straightens as it emerges into the sunlight.

14. Advantages of Dormancy
Allow for long-distance dispersal
Allow for seeds to germinate under ideal growth conditions
Some seeds need cold temperature before seeds germinate.

15. The graph shows germination rates for Arisaema dracontium gathered at two locations.
Interpret Graphs What effect does chilling have on germination of seeds from Ontario. How does it effect seeds from Louisiana
Form a Hypothesis Describe how the different rates of seed germination might be explained in terms of adaptation to the local climate