Exam 3 - Plant Taxonomy

Convergent Evolution Definition

• evolution of the SAME morphology that arose INDEPENDENTLY in different lineages

• Morphology was NOT present in ancestors, but evolved again multiple times

Convergent Evolution Examples

• Carnivory arose at least 9 times in flowering plants, each without common ancestors with those traits (different ancestors evolved into having carnivory). Same morphology that arose seperately

• pitchers evolved in 3 different countries so it has evolved many times

What is carnivory, why did it evolve

• Trap and consume animals to acquire nutrients such as Nitrogen

• Evolved for handling nutrient poor conditions

Why isn’t every plant carnivorous?

• They don’t need to because they can acquire it from the soil (nutrient rich or stable areas)

• Carnivorous can be costly

  • must produce rewards/incentives to trap animals

  • active traps use energy

  • producing sticky compounds

• tradeoffs between photosynthetic efficiency and investment in trap structures

Trap Types

pitchers, fly paper (sticky trap), snap traps, bladder (suction trap)

Pitchers

Fall traps

• insider of pitcher is smooth, bottom has bacteria/digestive juices

Evolved in australia, america, and asia

Sarranceniaceae, 3 species (flowers are tall as to not catch pollinators in pitcher)

Nepanthaceae (leaf = pedicel), very different than flowers in America

Fly Paper

Sticky substance to catch prey

Drosera (sundew)

• traps use glandular trichomes

• LEAVES ACTIVELY MOVE

• photosyn. and trapping = same part of leaf

Lentibulariaceae Pinguicula

• passive traps

• butterworts

• closely related to bladder worts

Snap traps

Venus Flytrap (Dionaea muscipula)

• action potential (electric signal) to close trap

• smart = can count and tell dif. between false alarm and bug

Bladder (suction trap)

Utricularia (bladderwort)

• extends bladder quickly to suck up prey

Pollination and why

= the process of reproduction for plants in which pollen is moved from the male (anther) to the female of another flower (stigma)

ensures cross pollination and gene flow amongst species

Pollination parts

male = anther with pollen (male reproductive cells)

female = pollen goes to stigma, then pollen enters ovule which becomes seeds and fruits

inflorescence = flower clusters, can be single unit of attraction, moves leaves out of the way for pollinators

bracts = modified leaves at the base of flowers/inflorescence, can be modified for attraction

Pollination syndromes + coevolution

Specific flower morphology that have relationships to specific pollinators, coevolve to have mutualistic relationships for pollination

Unusual pollination

Coevolution

Tube lipped nectar bat has an extremely long tongue to get the nectar out of flowers

reward/attraction is the nectar

pollen will get stuck to the hair on the bat and when the bat leaves to go to another flower it will transfer that pollen to the new flower

Wind Pollination

• large anthers, LOT of pollen

• small male flowers

• long and sticky stigma to capture pollen

NO PETALS BC DOES NOT NEED TO ATTRACT/ REWARD POLLINATORS

Animal Pollination

• flowers reward pollinator with nectar or tasty pollen

• signals evolved for specific animal groups

• hide pollen so that by the time they find it they are covered in pollen

Bunchberry

flowers = inflorescence, bracts = “petals”

catapult like filaments- once triggered at the top, the filaments spring open and fling pollen onto the pollinator and now the stigma is open to receive pollen

Dispersal and why

Seeds or fruit are moved away from the parent plant to a new location to grow

prevents overcrowding by the parent, prevents competition to that the plant may grow successfully, possibly move them to better suitable conditions

Dispersal structures

Seeds

• eliosome = lipid rich body, aids in mutualistic relationship with ants

• endosperm used to provide the seeds with nutrients when growing or transport

fruits

Dispersal classification

By agent

• zoochary (animals)

  • epizoochary = “on top”, stick to the coat of animals

  • endozoochary = eaten by animals

  • type of dispersal (myrmecochory = ants)

• anemochory (wind)

• hydrochory (water)

• autochory (self dispersal)

Evolutionary anachronisms

traits that were better suited for prior times that not have not evolved out of the environment/organisms

ex. giant fruit that might be too hard to open, spiny, or inaccessible to dispersers, so they are not able to be eaten or dispersed by anything nowadays

Janzen paper

In lowland forest flora in Costa Rica, there are plants that produce large fruits that currently have no dispersal method. They conclude that these fruits were evolved to be eaten by megafauna during the Pleistocene period as the dispersal method for the fruit. Because these plants can have lifespans of 100-500 years, they have not been able to evolve more edible fruits that are not meant for megafauna. (unable to adapt quickly enough)

megafaunal dispersal syndrome

Pitcher Plant Species / Names

Sarranceniaceae, 3 species (flowers are tall as to not catch pollinators in pitcher)

Nepanthaceae (leaf = pedicel), very different than flowers in America

Sundews

Drosera

butterworts = Lentibulariaceae Pinguicula

Fly Trap Name

Dionaea muscipula

Bladderwort Name

Utricularia