1. Announcements
Take out packet to be checked from last class if you did not get it stamped
Work on energy do now
Extra Credit due FRI 12/4
Unit 4A Test WED 12/16, THURS 12/17

3. Energy in Food: Producers
The energy in the food we eat originates from the sun
The beginning of every food chain starts with a producer
Producers are known as autotrophs because they can use the energy from the sun to make glucose (photosynthesis) Plants are the main terrestrial producers.

4. Ancestors of the Plantae
The Plantae evolved from green algae, most likely a group called the charophytes.
Evidence:
Cell wall structure of both is very similar
DNA sequence data supports close relationship between these groups.

5. The transition to Land The risks: Harsh environment…
Heat, drying out, damage by UV rays
The rewards: Great opportunity…
Plentiful CO2, sunlight, few competitors or herbivores.
The importance:
paved the way for other organisms: Food for herbivores; First soils!

6. Overcoming Challenges of life on land
Avoid drying out. (Waterproof Covering)
Be able to hold itself up (Strong Cell Wall)
Possess differentiated tissues because air and soil differ in composition and resources. (Roots, Stems, Leaves)
Solve the problem of reproducing outside water. (Seeds)

7. Transition to land
The ancestor of modern plants once established on land had enormous opportunities because there was no competition for sunlight or minerals and no herbivores.
Selection rapidly led to a massive diversification of plants.

8. First Land Plants
The first land plants were nonvascular plants (like mosses today)
This means they didn’t have roots or stems so they could not transport water, sugars or minerals around the plant.

9. First Land Plants
Lack of vascular tissue also limited the size of plants (since they can’t transport nutrients around the plant) and required them to live in very moist environments.

10. Rise of Vascular plants
Once the first plants moved onto land, selection quickly led to the development of specialized roots and shoots to move water and other essentials around the plant
The first vascular plants were ferns and other seedless plants.

11. Limits to early vascular plants
Ferns reproduce with spores which are fragile and have a short lifetime
Mosses and ferns need rainfall to help fertilize spores

12. Evolution of pollen and seeds
Pollen dispersal is not limited by rainfall
Seeds provide protection and nourishment for developing embryo.

13. Gymnosperms The first seed plants
Most gymnosperms are cone-bearing plants (Conifers)
Conifers with their needle-like leaves are adapted to cold dry weather so they dominate northern temperate regions.

14. Other Gymnosperms
Ginko
Cycads

15. Angiosperm diversification
Angiosperms= flowering plants
Have been enormously successful.
There are now about 235,000 species in comparison to just over 700 gymnosperms.

16. Monocots Vs. Dicots Angiosperm are divide into 2 classes
dicots (eudicot)
2 cotyledons (seed leaves)
leaves with network of veins
woody plants, trees, shrubs, beans
monocots
1 cotyledon
leaves with parallel veins
grasses, palms, lilies

17. Flowers and Fruit Fruit Flower
The key to the success of the Angiosperms has been that they have evolved flowers and fruit.
Fruit
Protects the seeds
Animals eat the fruit and spread the seeds.
Flower
Bees, bats, birds, etc. are attracted to flowers by the nectar. When they visit multiple flowers they move pollen from one to the next

18. Flower Dissection Male Female
Although flowers vary widely in appearance they have certain structures in common.
Male
Female