What is the taxonomic hierarchy?
- Class
- Order
- Family
- Genus
- Species
What is physiognomic classification?
Grouping plants upon similarities in structure or life-form
Two individuals may have similar structure, but be genetically distant
What are the layers of a forest?
- Moss layer
- Herb layer
- Shrub layer
- Tree layer
- Crown of a tree - comprise a canopy (closed canopy when they overlap)
Define a tree, shrub, liana, herbaceous, forb, graminoid, epiphyte, fern
- Tree: perennial, erect woody plant with a single upright main trunk
- Shrub: a woody plant having several stems branching near the ground
- Liana: vines - woody stems
- Herbaceous plant: lack woody stems, usually shortewr then trees
- Forbs: dendritic or webbed venation flat wildflower
- Graminoids: parallel venation, narrow leaves (can be arboreal - tree height)
- Ferns: reproduce with spores rather than seeds
- Epiphytes: use other plants as supporting structure, not rooted in ground. But they do not take nutrients or energy from the plant they grow on: not parasitic
Forest vs woodland
- Forest: vegetation where tree grow together
- Woodland: vegetation where trees are spaced so taht crowns are separated.
What are two main influences on plant growth?
Temperature and water
Strategies for plants to minimize water loss. What are plants in dry condition called?
These plants are called xerophytes
- minimize water loss with a thick epidermis
- Special coating
- Less surface area, maybe no leaves at all (spherical shape, no leaves)
- Spines slow air flow across the epidermis, slowing evaporation and reduce herbivory
- Reduce number of stomata/ amount of time they are open
- Deep roots allowing them to “tap” groundwater
- Succulent tissues ( store water in stems, leaves or roots)
- Deciduous habit - become dormant, reducing water needs
What strategies do plants have in high water environments? (water is never limiting)
- Drip tips
- High productivity means they compete for light, however there is a very dense canopy so they have larger leaves to capture light better
- Abundance of moisture allows plants to have large leaf surface area due to no stress in terms of moisture loss through transpiration
What is afforestation vs reforestation?
Afforestation is planting on land that has not historically contained forest
Reforestation is planting on land that has historically contained forests
How much area must be covered for it to be considered a forest?
minimum 0.05 - 1.0 ha with tree crown cover
Explain temperature limits of plants - COLD
- Decreasing temperatures cause a decrease in metabolic rates
- Freezing can cause cell damage if ice crystals form in cells - physically damage to the cell and tissues
- Cold tolerant species can expel excess water from cells to spaces between cells, where freezing will do no damage
Explain temperature limits of plants (HOT)
- High temperatures can cause stress- increase respiration and water loss
- High metabolic rates with physiological, biochemical and molecular changes in plant metabolism
How is altitude related to biomes?
With increasing elevation, there is a temperature decrease and evaporation decrease, contributing to sequences of vegetation zones related to altitude
Name characteristics of a desert biome
- Low P, High aridity
- High water evapotranspiration
- Deserts precipitation is less than 1/2 its evapotranspiration
What is allelopathy?
Some plants can release toxins from their roots, this prevents other plants from growing too close
Name 5 characteristics of grasslands
- Fire is common
- Tall grass prairies with high number of forbs
- Chernozem soil
- Best for agriculture
- Endangered ecosystem
What are 5 characteristics of the mediterranean shrub land? (name of vegetation type)
- Adapted to dry conditions
- Highest precipitation in winter (too cold for it to be properly utilized)
- Sclerophyllous vegetation (Scler = hard, phyll = leaf)
- Many plants that grow here have hard, leathery leaves with a thick cuticle
- High exploitation
East to West of USA, what is biome gradient?
- Broadleaf deciduous forest
- Woodland/Savanna
- Prairie and grassland
- Desert
Tree diversity declines as we go west, it gets drier and drier
What is the biome gradient from the equator to the tropic of Cancer in Africa?
- Tropical Rain Forest
- Grasslands (Savanna)
- Deserts
Describe the soil of tropical rain forests
Leeched - high iron content, high OM cycling so it never soaks into the soil
Describe biome gradient from Arctic Circle to North Africa Coast
- Tundra
- Boreal Forest
- Broadleaf
- Mediterranean Shrub Land (Chaperall)
What are main characteristics of the Tundra biome?
- Greatest adaptation to low temperatures
- Short growing season
- Permafrost
What is the biome gradient with increasing elevation?
- Tropical rainforest
- Broadleaf deciduous
- Boreal
- Tundra
