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Key Features

LECTURE OVERVIEW

Basic statement:

Interactions between plants and animals are far more complex than the simple observation that animals eat plants. Reciprocal selection has produced intriguing and widespread dependencies among trees and their animal associates.

Key ideas:

The fossil record reveals one of the best examples of coevolution: the contemporaneous expansion of angiosperms and insects during the Cretaceous period. Coevolutionary interactions in the current environment are only a recent topic of scientific investigation. Investigations are being carried out using a combination of approaches: observation, correlation, experimentation and modeling. Coevolutionary interactions under current study involve such processes as pollination, defoliation, seed predation, seed dispersal. Traits involved in these interactions are diverse (e.g., biochemicals, mechanical structures, timing of life-history events).

Important terms:

Coevolution

EXAMPLES IN BOTANY GREENHOUSE (corpse flower ppt)

COEVOLUTION: Reciprocal evolutionary changes between organisms due to interactions between them.

Ant-Plant Relationships (domacia= structures that house ants—evolved from very different structures: leaves, stems, stipules)

swollen thorn Acacia

Plants provide

• thorns lodging
• petioles nectaries
• leaf tips Beltian bodies with proteins and fats

Ants provide

• protection from insect predators (pheromones)
• 30,000 patrol one plant
• attack people, too

Cecropia (sp?)

• ants live in stem, mullerian bodies produce proteins (non visible), plant is 2.5 yrs

Myrmecodia, Rubiaceae, Epiphyte

• ants live in stem
• attack invader (including people) when leaf depressed (pheromones)
• warty chamber absorbs food from ant debris
• smooth chamber rears ants
• ants forage on ground and pick up nutrients
• birds disperse seeds (demonstrate)

Asclepiadaceae example (related to milkweed)

• hollow leaves rear ants
• roots invade leaf chambers for nutrients

General Tropical Room (questionable co-evolution)

flower resembling rotten meet

• traps flies in chamber
• hairs wilt to release flies
• anthers and pistils mature at different times

plants with big leaves

leaves look like they have been chewed or leaf mined, predators go elsewhere

Amorphophallus (sp?)—just interesting

• monsoon region of Sumatra
• in monsoon season grows one huge leaf, 6"/day, 8’ total
• leaf dies in dry season, dormant in underground tuber
• giant arum type flower, see deVries picture
• fruit, inflorescence of berries

Diascoria

• drip tips leaves
• tubercles, asexual reproduction (abscise when mature)
• source of estrogen and testosterone

Hall

Walking sticks—not really co-evolution

mimic dead leaves on thorny stems

baby looks like stinging tropical ants with orange heads

eggs have structure that ants eat as they are dispersing eggs

Carnivorous plant and orchid room—not really coevolution

Discuss reasons for carnivory

• Pitcher Plants
• Sun dews Drosera

  aroma attracts ants
  ant sticks to leaf
  leaf curls around ant
  epidermis secretes digestive enzymes

• Utriculara catches Daphnia
• Napenthes--
  • a large group of plant that have carnivorous leaf tips--
    same function as other carnivorous plants.
    they occur all over the tropics
    often grow on other plants
    so they are not connected to the ground and must get nutrients from animals. .
    

Orchid adaptations for pollination

Dracula plants

• mimic shelf fungi (correct to genus)
• pollinated by gnat that lays eggs in mushrooms and larvae eat mushroom

Dracula vampira

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