Please enable JavaScript.
Coggle requires JavaScript to display documents.
Populations and Ecosystems (Concepts (Population (Dioecious or self…
Populations and Ecosystems
Concepts
Population
An individual never exists in isolation
Other individuals of same species together
Dioecious or self-sterile individuals
Individuals can not do it alone
Population can carry out successful sexual reproduction
Pollination
Population of plants can sustain population of pollinators
One individual cannot produce enough nectar/pollen
To keep even one pollinator alive
Negative side of populations
Populations may be dense enough
Spores from pathogenic fungus are ensured to land
On one susceptible individual and then spread
If individual could exist in isolation
May be safe from pathogens, predators, and naturals events
Example: natural fires
Community
All of the populations together
Numerous plant species and numerous animal species
Example: Animals, Fungi, Protists, and Prokaryotes
Ecology
Study of organisms in relationships to surroundings
Ecosystem
#
Community is similar to ecosystem
Levels of interactions and complexity are higher
Populations are rarely stable
Plants in Relationships to their habitats
Abiotic Components of Habitats
Soil Factors
A Horizon
Uppermost layer of thick soil
Also known as zone of leaching
Consists of litter and debris
As it breaks down
Rainwater washes nutrients from it downward
B Horizon
Below A Horizon layer
Also known as zone of deposition
Material from A horizon accumulates here
Rich in nutrients
Contains
Humus
Clay
Pioneers
First plant to invade new soil
Must tolerate severe conditions
C Horizon
Below B Horizon/ Lowest layer
composed mostly of
Parent rock
Rock fragments
Soil formation
breakdown of rocks
Initial result is think
virtually identical to parent
Latitude and Altitude
Latitude
At the equator
No seasonal variation occurs
Plants cannot measure season/photoperiod
All days are 12 hours long
At a higher latitude
Summer days become longer
As do winter nights
Either North or South
Sun is only rarely overhead
Usually only near mid-summer
Temperature fluctuates greatly
Above arctic and Antarctic circles
Mid-summer days are 24 hours long
As are winter nights
At intermediate latitudes
Day length is excellent indicator of seasons
Some species are sensitive to photoperiod
High altitudes
On mountain tops
Similar to high latitudes
May have varying day length, depending on latitude
Stress present on high altitude
due to ultraviolet light
Above much of Earth's atmosphere
Not fully shielded by
oxygen
carbon dioxide
water vapor
Ozone layer
Climate
Critically important to all organisms
Most species are restricted due to climate
Climate conditions may be
Temperature
Rainfall
Relative humidity
Wind
Tolerance Range
#
Between low and high extremes
Ranges vary greatly from species to species
Disturbance
Phenomena such as:
Fires
Landslides
Snow avalanches
Floods
Significant, radical change in ecosystem
Affect biotic factors directly
Eliminate large numbers of individuals in area
Little or no impact on abiotic factors
Nonliving factors/ Physical Phenomena
Biotic Components of Habitats
The plant itself
Can be its own habitat
Habitat Modification
Detrimental
Neutral
Beneficial
Other Plant Species
Mutualism
When interaction is beneficial for both
Competition
When the interaction is disadvantageous
When 2 population don't grow well together
Compete for limited resources
Light
soil nutrients
Water
Attention from pollinators
Competitive Exclusion
Result of competition
Less adapted species is excluded
By superior competitors
Superior competitor wins
Does not get excluded
Ecotypes
Once known as subspecies
Each one specialized in response
Environmental factors at locality
Transplant experiments
To test if ecosystem exists
Plants are transplanted to alternate site
Common Garden
Plants from both sites grown together
Occurs at intermediate site
Organisms other than plants
Commensal Relationships
When one organism is benefited
And the other organisms is not affected
Common between plants and animals
Predation
Relationship one is harmed
Other organism is benefited
Herbivores
Herbivory
Browsing
Eats twigs, leaves, shrubs
Ex) Deer and Giraffe
Grazing
Eats herbs
Ex) sheep and cattle
Pathogenic
Interrelationship
Typically between plants and fungi
Harmful to plants
Rather than predatory
Habitat
Set of conditions organisms complete in life cycle
No plants are migratory
But portions of plants move inside their habitat
Pollen
Fruits
Seeds
Spores
Vegetative propagules
Migratory birds have several habitats
Summer Area
Migration Route
Winter Area
All components that effect or don't effect
Operational Habitat
aspects of habitat that affect the plant
Pollinators are critically important
Herbs are vital to success of giant redwoods
The structure of Populations
Age Distribution: Demography
population responds to various factors
demography
Relative proportions of individuals
Generation Time
Birth of first born to birth of first offspring
Affects rapidity
Intrinsic rate of natural increase
Also known as biotic potential
#
number of offspring produced by individual
Reproduce under ideal conditions
Carrying capacity
How many individuals can live in specific region
Symbol is K
When a population comes close to K
Competition and crowding become factors
r- and k- selection
r- Selection
Adaptive in r-sites
Early Maturity
Many small Seeds
Annual
Few mechanical or chemical defenses
k- Selection
Adaptive in k-sites
Late maturity
Fewer, larger seeds
Many defenses
Perennial
Geographic Distribution
Boundaries of the Geographic Range
Ability to spread throughout geographic region
Result of adaptations
Abiotic
Biotic
Limited factors
One factor alone determines health
Ex) Photosynthesis
Applies to all plant interactions
Any factor can be a limited factor
Biotic Factors
Are critical
Water
Needed for plant growth
Soil Factors
Produce abrupt boundaries
Mineral composition and soil texture
Local Geographic Distribution
Random Distribution
No obvious pattern to position
No predictable values
Knowing position of one
Does not mean you know position of others
Plants distributed at random
May be due to many small patterns
Uniform Distribution
Individuals are all evenly spaced
Types that occur in orchards/tree plantations
Clumped Distribution
Spaces between plants is small or large
Rarely average
Can result from many factors
Seeds
Allelochemics
Allelopathy
Inhibition
Ex) Purple Salvias of California
Plant chemicals
The structure of Ecosystems
Species composition
Number/diversity of coexisting species
Depending factors
Weather climate
Soil nutrients
Species tolerance range
Trophic Levels
#
Primary Producers
Autotrophs
First step of any food chain
Supply energy/food to herbivores
Primary Consumers
Herbivores
Also known as secondary producers
Food from autotrophs
Preyed on by carnivores
Secondary Consumers
Carnivores
Omnivores occur at primary and secondary levels
Decomposers
fungi and bacteria break down
Material of dead organisms
Are basically feeding levels
Temporal Structure
changes of ecosystem under time constitute
May be short like one day
May be an entire decade
Gradual changes
Physiognomic Structure
Physical size and shape of organisms
Three most useful categories
Trees
Shrubs
Herbs
Life Forms
Defines by C. Raunkiaer in 1934
Means of surviving stress
Types of Life forms
Hemicryptophytes
Buds are located at surface of soil
Protected by leaf and stem
Ex) Many grasses and rosette plants
Chamaephytes
Buds are located above ground
Low enough to not be exposed to winds
Ex) Small shrubs
Geophytes
Buds are underground on
Bulbs
Corms
Rhizomes
Therophytes
Annual life span
Survive stress as seeds
Phanerophytes
Buds are located high of shoots
At least 25-30cm above ground
Ex) trees and large shrubs
Biotic components are also a factor in age distribution
Trophic levels have several biotic components in them
Ecosystem are similar to trohic levels
Both have a tolerance range