25.3: Lab Report
A1. View the bryophytes on display. Compare and contrast the overall morphology of bryophytes to the plants you can see outside. Why do you think the bryophytes all share such a similar growth form?
A2. Which part of the sporangium is the oldest? How do you know?
Make a wet mount of a small piece of hornwort thallus or obtain a prepared slide. Can you tell how many chloroplasts are in it? Draw this cell in the space below and label the chloroplasts and any other features you recognize.
C1. Pollination is essential for producing offspring. Because of this, it serves as a strong driver of selection in angiosperms. Flowering plants have evolved to utilize different pollinators, such as wind or birds, to transport their pollen to other flowers of the same species. Some of these pollinators, such as wind, are not selective and rely on producing large quantities of pollen. Others, like hummingbirds, require large quantities of nectar and are attracted by particular colors. Use the table of pollination syndromes below to determine the likely pollinator for the flowers available in your lab.
|
Color |
Structure |
Scent |
Nectar or Pollen |
|
|---|---|---|---|---|
|
Wind |
Dull, perianth often absent or reduced |
Large feathery stigmas, large anthers |
None |
No nectar, large amounts of pollen |
|
Birds |
Reds and pinks |
Often tubular or cupped |
None |
Lots of hidden nectar, moderate pollen |
|
Bees |
Purples, blues, yellows, white, UV |
Flat and shallow or tubular, with landing area |
Sweet, fresh, mild |
Pollen often sticky and scented, nectar usually present |
|
Bats |
White, dull green, or purple |
Often bowl-shaped or pendant, anthers protruding |
Musty or fruity, strong, emitted at night |
Lots of hidden nectar |
|
Moths |
White, pale pink or purple |
Often tubular or cupped, no landing pad |
Strong and sweet, emitted at night |
Lots of hidden nectar, limited pollen |
|
Butterflies |
Bright colors |
Tubular, with wide landing pad |
Faint, fresh |
Lots of hidden nectar, limited pollen |
|
Flies |
Dark red, purple, brown |
Shallow, funnel, or trap-like |
Putrid, rotting |
No nectar, moderate pollen |
Who is the pollinator?
Record the most likely pollinator and the trait(s) in the flower that lead you to this conclusion:
1.
2.
3.
4.
5.
C2. Different fruits have evolved in response to different dispersal agents . The fruits that we buy at the grocery store are tasty because they have evolved for animal ingestion. The burrs that get stuck to your socks when you walk through a field have evolved for animal attachment. How can we use characteristics of fruits to predict the dispersal agent?
Observe the fruits available and use the table below to predict which characteristics are related to each of the following dispersal agents.
|
Dispersal Agent |
Expected Characteristics |
|---|---|
|
Animal ingestion |
|
|
Animal attachment |
|
|
Wind |
|
|
Water |
|
|
Ballistic (explosive, projectile) |