Please enable JavaScript.
Coggle requires JavaScript to display documents.
Populations and Ecosystems (Structure of Ecosystems (Species Composition…
Populations and Ecosystems
Plants & Relationship to habitats
Biotic Components.
Other Species
Possibility of interaction is created when multiple plant species grow close to each other.
Mutualism
Generally beneficial "arrangement" between both plants.
Competition
#
Situation where the plants don't grow as well together as they do separately. Competition for light is extremely common.
Other Organisms
#
Commensal relationships may be formed, such as birds making nests in trees. Birds get a home, trees are left unharmed.
Predation is possible, herbivores being a direct threat to easily-reached plant life.
Cattle and deer are good examples, though insects may lay eggs where the offpsring eat the plant for nutrients.
Animals, fungi, and prokaryotes have a definite effect on a plant.
The Plant
Just being there itself modifies the habitat.
Modification may be beneficial, detrimental, or neutral.
Some trees modify the habitat by producing a canopy, providing an environment suitable for their own seedlings.
Abiotic Components
Soil Factors
A Horizon
Uppermost layer of soil.
"Zone of leaching".
Consists of litter and debris.
B Horizon
Zone of deposition.
Area where materials from A Horizon accumulate.
Pioneers
First plants to invade new soil.
C Horizon
Beneath A and B Horizons
Mostly parent rock and rock fragments.
Soil is formed by breakdown of rock.
Latitude and Altitude
Contributes a vast amount to abiotic factors.
Light energy can change depending on latitude. Equatorial areas receive a great amount. Polar areas receive little.
Regions at high altitude are similar to those at high latitude.
At high points, life becomes nothing more than small shrubs and grass or nothing at all.
Climate
Affected by latitude and geographic features like mountains.
Critically important to the survival of anything in a given area.
Tolerance range
Range in which life can carry on, or proceed optimally.
Average temperature is not as important as the extremes.
Structure of Populations
Age Distribution
Generation Time
Length of time from birth of one individual to its offspring.
Annuals
Generation time of around one year.
Most conifers are nowhere near as fast in growth and generation time.
Biotic Potential
Intrinsic rate of natural increase.
Number of offpsring produced by an individual that live long enough to reproduce under ideal conditions.
Even under optimal conditions, a large percentage of seeds don't germinate, with more dying before reproduction.
Biotic potential does not equal number of seeds produced.
r/K Selection
#
#
r-Selection
A disturbance usually produces r conditions.
Fires may leave few plants with a large amount of resources to reproduce in large quantities.
r-selected species are typically annuals or small shrubby plants.
As more species return, r species come down to a disadvantage.
k-Selection
k-selected species are polar opposites of r-species.
k-species are focused on quality over quantity.
Conditions in a crowded habitat close to carrying capacity fuel the process for k-species to come about.
For these species, it is advantageous to live for a long time.
Geographic Distribution
Boundaries
#
Limiting factor
Factor in which ultimately determines how well something may grow.
Light intensity and CO2 available is a solid example for plant life.
Limiting factors can change when certain thresholds are met. It can switch from water availability to sunlight availability and back again.
Desert regions
A major limiting factor is availability of water
Certain adaptations by plants help preserve their water reserves, helping to ease their growth and somewhat neutralize the limiting factor of water.
Rainy zones
Plants that commonly get more rain may not benefit much from more of it, but instead more light.
Competition for light in rainforests is fierce, and is certainly a major limiting factor in those environments.
Local Distribution
Random Distributions
When there is no identifiable pattern to position of individuals.
Most habitats are of the random distrib. type.
Clumped Distributions
Spacing between plants is small or large, but rarely average.
Can result from many factors
Seeds falling near a plant.
Birds or animals "depositing" seeds in one small area.
Geographic topography can cluster things into a small area.
Uniform distributions
Occur in orchards and tree plantations.
All individuals are evenly spaced.
Not extremely common in nature.
Can be created through competition and release of chemicals
Allochemics and allelopathy are both used by plants to "mark" territory and prevent other plants from growing there.
Structure of Ecosystems
Temporal
Like animals having daily cycles of activity, plants can have them as well.
Changes an ecosystem undergoes with time.
Species Composition
Stressful climates with poor soils hold a low species composition due to lack of inhabitants.
Competition is typically intense, but natural selection has resulted in a sort of partitioning system between species.
Number and diversity of a species within an ecosystem.
Physiogenic
Trees, shrubs, and herbs are the most useful categories.
C. Raunkiaer developed a system in 1934 for better classification.
Physical size and shape of organisms and distribution in relation to each other and to the physical environment.
Trophic Levels
Essentially another way of saying "feeding levels".
System of four groups
Decomposers
The lowest level, they receive the least energy. Fungi and bacteria rest in this level.
Primary Producers
Autotrophs. They are the energy and nutrient supply for herbivores.
Secondary consumers
Carnivores. These prey on the herbivores, gaining an even smaller amount of energy.
Primary Consumers
Herbivores themselves. They receive a sllightly lower amount of energy.
Kudzu, an extremely competitive/invasive plant that has excelled in making sure it survives.
