Chapter 24

Ecosystem Structure & Function Chapter 24

Questions to AnswerBased on the vegetation in the picture on 632, what inference can you make about the climate there?

How have plants adapted to that environment?

How are those adaptations different from costal plants in Savannah or the environmental factors of Dexter? Interactions & InterdependenceThe environment changes organisms and organisms also change the environment

This relationship is a product of evolution through natural selection

Section 1: Abiotic FactorsWhat are abiotic factors?

Climate and other physical conditions limit the geographical range of many species.

Ex. Bacteria in hot springs have enzymes that have evolved to function best at high temperatures where as our enzymes and other proteins begin to denature around 105o .

Other limiting abiotic factorsWater availability Adaptations include: Active transport in ocean fishThick cuticles in cactiNocturnal behaviors SunlightLarger leaves in understory Other limiting abiotic factorsPhysical StructurespHSoil compositionAdaptations include symbiotic relationshipsAbiotic CatastrophesFloods, fires, avalanches, etc. can cause changes in ecosystems.Specifically they can lead to secondary succession and at times primary succession

Biotic affect on AbioticPlants roots help break down rocks into soil and also help prevent erosion.

Decaying organic materials contribute to the fertility of the soil and its composition.

Transpiration from forest contributes to the humidity of the surrounding environment.Plants & Salt Tolerance pg. 636Plants growing in coastal areas must adapt to the high levels of potentially toxic sodium(Na), chloride(Cl already ionized) and carbonate (CO3).

Adaptation for survival: specialized cells that concentrate the sodium and chloride that are absorbedThe accumulated salt is stored externally in bladders maintaining normal levels internally. Example plant saltbush

Section 2: Energy in Food WebsAutotrophs vs Heterotrophs

Photosynthesis ultimately determine the amount of energy available for most ecosystems (terrestrial and photic)What would provide energy to the aphotic ecosystems?

Nutritional relationships among the producers and consumers in an ecosystem form its trophic structure.

What are some primary and secondary consumers in terrestrial and aquatic ecosystems?

What organisms would be primary decomposers?(how do they breakdown the material?)Just as available energy declines near the peak of the energy pyramid, the biomass at each trophic level also decreases.

The Productivity of an ecosystem is highest among the producers and declines at higher trophic levels

Section 3: Relationships in EcosystemsSymbiosis and Predation

Competitive exclusion The more two species resemble one another in their patterns of resource use, the more they will compete with each other.

Adaptations that enable competing species to divide and share the resources reduce competition

Adaptive radiation also helps reduce competition Section 4: Nutrient CyclesPlease refer to text for details and enjoy the handout for a summary

Chemical elements in the ecosystems are limited and must be recycled.

You need to know the parts to each cycle. How the elements move through the biosphereSection 5: limiting factorsVarious factors limit the productivity of ecosystems.Limiting Factors include but are not limited to: Water Soil Composition (amt. of nitrogen)TemperaturePredatorsProducers

Section 6: Population DynamicsTypes of population growth:Logistic Exponential

Population growth-limiting factors include:Food availabilitySpaceMate optionsCompetition Reduced reproduction rates and increased death rates can slow population growth.

When population growth approaches a stable maximum it has reached its carry capacity

Terms to review:Carrying Capacity and Population Density

Boom-and- bust cycleWhen a population grows exponentially and quickly exceeds the carrying capacity causing a rapid decline in reproduction and sharp increase in the death rate.

Final Thoughts

Variations in population size of one species can ripple through and ecosystem causing changes in many other populations.

Populations are always changing making it difficult to accurately determine the cause of the change.

Ecosystems are complex fluctuating systemsLearning ObjectivesLO 4.13 Student is able to predict the effects of change in the communitys populations on the community

LO 4.16 Student is able to predict the effects of a change in matter or emery availability on communities.