Conditions and resources

environmental conditions

physicochemical features of the environment
(temperature, humidity, pH, salinity)

characteristics of environmental conditions

not consumed or usd up by organisms
can be altered by organisms
on varying scales( a tree affecting humidity)

environmental resources

elements consumed by organisms for growth and reproduction

examples of environmental resources

sunlight, water, nutrients

environmental resources characteristics

directly affect competition among organisms
(eagles competing for rabbits as food)

relativity

what is extreme or harsh for one species may be benign for another
ex desert conditions for cati vs penguins in Antartica

ecological caution

ecologists should avoid anthropocentric terms when describing conditions

Bell shaped response to conditions

temperature where extremes are lethal, but there's a range for growth and reproduction

Threshold response to conditions

-toxins like arsenic where effects only appear above a certain concentration
- required but toxic at high levels e.g salts where low levels are essential, but high levels are lethal

Temperature effects: Biological processes

often increase with temperature but may fall at excessively high levels

Temperature effects: Growth Development

Typically linear up to a pt. but vary among species, affecting final size

Extreme temperature effects :High temperatures

can cause dehydration, protein denaturation, and eventually death

Extreme temperature effects : Low temperatures

may lead to chilling injury or freezing but in some species have adaptations like antifreeze proteins

Temporal and Spatial Aspects: Timing and Duration

critical in determining the impact of env. conditions(e.g frost killing seedlings but not mature plants)

Temporal and Spatial Aspects: Frequency of extremes

can shape specks distribution more than average conditions

Conditions as stimuli
Anticipation of seasonal changes: Photoperiod

used by organisms to prepare for upcoming seasonal changes (e.g bears thickening fur, insects entering diapause

Conditions as stimuli
Anticipation of seasonal changes: Germination and Growth

seeds may require chilling or specific photoperiods before germination

Conditions as stimuli: acclimatization

organisms adjust their physiology to better with stand changing conditions

Infraspecific Competition

competition between individuals of the same species for limited resources

Resource depletion

competing individuals deplete available resources, affecting each others survival

exploitations competition

indirect interaction through shared resources

interference competition

direct interaction, such as fighting or territorial disputes

effects of conditions

lower available resources, reduce growth and reproductions

mortality rate

increases with density

birth rate

decreases with density

High density

more significant competition effects as resource depletion zones overlap more

density dependent effects

as crowding increases, per capita birth rates decline, death rate increases

density independent effects

per capita birth rates may remain constant

Ecological Niche

A specific role/lifestyle of a species within an ecosystem, including its use of resources, and relationships with other species.; how an oraganism lives not where it lives

habitat

the physical environment where an organism lives

N-Dimensional hypervolume

the modern concept of the niche involves multiple dimensions, capturing all the conditions and resources required by a species

Stomatal regulation

controlling the opening and closing of stomata to balance gas exchange and water conservation

Plants and C

High C ratio

algae and C

lower C ratio

Aposematic Coloration

bright colors to warn predators of toxicity or danger

Mimicry

resembling other organisms or objects or objects to deceive predators

Ectotherms

animals that are not able to control their body temperature

Endotherms

Animals that can regulate their body temperature.

Photosynthesis

requires open stomata for CO2 but allows water vapor to escape

Camouflage

helps avoid detection

NPK

the most important soil nutrients for plant growth

autecology

-auto= self
-organisms response to conditions
-interactions b/w organism and the environment
-where does the org. occur and why
-effect of [env. variable] on the dist. and abundance of [org]

ecological amplitude

The limits of environmental conditions within which an organism can live and function

ecological optimum

refers to the environmental conditions under which a species will prosper

guild

group of species that use the same resources

Principle one of Autecology

organisms must maintain a possible carbon balance

Principle 2

organisms must avoid excessive risk

ring porus wood

large vessels early in the year

Diffuse Porus Wood

medium sized vessels constantly distributed

Cavitation

when gas bubbles occur in the xylem thawing; stops conducting; that vessel becomes useless

Whay porus is more prone to cavitation

ring porus

indeterminate growth

growth that is not terminated once buds; always growing

determinate growth

once fruits then stops

If plants need the same resources, why do different plant species have different distributions?

Niche Specialization: Each plant species often occupies a unique ecological niche, meaning they have specific conditions under which they thrive best; liebig’s law of the minimum

Liebigs law of the minimum

that the growth or success of an organism is not determined by the total amount of resources available, but rather by the scarcest resource (the "limiting factor")

Decomposer

feed on already dead plants and animals

parasites

feed on one/ few hosts, do not kill hosts

predators

feed on many prey kill prey

Grazers

feed on many prey, kill prey

Specialists

focus on particular parts of prey or specific species

generalists

feed on a wide variety of foods with preferences and rank orders

Challenges of eating plants

• cell walls of indigestible lignin, cellulose, other structural carbohydrates

• C:N ratio exceeding 40:1

• carb-rich but limited in N

• need N for protein

• different species and tissues are nutritionally diverse

• different species and tissues are nutritionally diverse

  • secondary compounds

Secondary compounds

used by plants to deter herbivores

constitutive defenses

secondary compounds that are produced constantly

inducible defenses

secondary compounds that are only produced when attacked

apparency theory

plants that are more apparent or visible to herbivores—because they are larger, longer-lived, or more common in an ecosystem—tend to face greater herbivory pressure. As a result, these plants have evolved stronger, more generalized defenses.

• explain why some plants invest heavily in defenses while others rely on different strategies to survive and reproduce.