Ecosystem Structure & Function Chapter 24

Questions to Answer Based 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 & Interdependence The environment changes organisms and organisms also change the environment This relationship is a product of evolution through natural selection

Section 1: Abiotic Factors What 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 105 o.

Other limiting abiotic factors Water availability Adaptations include: Active transport in ocean fish Thick cuticles in cacti Nocturnal behaviors Sunlight Larger leaves in understory

Other limiting abiotic factors Physical Structures pH Soil composition Adaptations include symbiotic relationships

Abiotic Catastrophes Floods, fires, avalanches, etc. can cause changes in ecosystems. Specifically they can lead to secondary succession and at times primary succession

Biotic affect on Abiotic Plants 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. 636 Plants growing in coastal areas must adapt to the high levels of potentially toxic sodium(Na), chloride(Cl already ionized) and carbonate (CO 3 ). Adaptation for survival: specialized cells that concentrate the sodium and chloride that are absorbed The accumulated salt is stored externally in bladders maintaining normal levels internally. Example plant  saltbush

Section 2: Energy in Food Webs Autotrophs 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 Ecosystems Symbiosis 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 Cycles Please 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 biosphere

Section 5: limiting factors Various factors limit the productivity of ecosystems. Limiting Factors include but are not limited to: Water Soil Composition (amt. of nitrogen) Temperature Predators Producers

Section 6: Population Dynamics Types of population growth: Logistic Exponential Population growth-limiting factors include: Food availability Space Mate options Competition

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 cycle When 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 systems

Learning Objectives LO 4.13 Student is able to predict the effects of change in the community’s populations on the community LO 4.16 Student is able to predict the effects of a change in matter or emery availability on communities.