Geology 105 - Paleontology
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Paleoecology

Reading: Chapter 4

We're going to skip the beginning of this chapter. Start at Habitats and Niches on p. 84 and read through to the end of the subsection called Describing Fossil Communities (ends on p.94). Then read the box on p. 4-3 about Ecological Interactions.

Background

Terms:

ecosystem - large-scale ecological space, including all physical and biological factors
community - association of organisms in an ecosystem. Some members of a community may interact, others may simply coexist in the same area.
habitat - physical environment of a specific organism
niche - "job" of an organism; the place it occupies and role it plays in the ecosystem
intertidal - between the high and low tide line
subtidal - below the low tide line, on the continental shelf
pelagic organisms live in the open ocean, either on the contental shelf (neritic) or in the deep ocean (oceanic)
trophic structure - feeding relationships between organisms in an ecosystem, represented by a food web
What evidence about trophic structure and community structure is lost in fossilization?

 

Key Concepts and Questions:

1. What physical aspects of the environment limit where and how organisms live?

For each limiting factor, describe how that factor varies in the ocean, and how the factor affects the biology of organisms:

Factor
How does it vary?
How does it affect organisms?

 

Temperature

 

 

Oxygen

 

 

Salinity

 

 

Depth/Light

 

 

Substrate

 

In class we will apply this framework to these environments:

Environment How do limiting factors vary? Adaptations we expect to see

 

Rocky intertidal

 

   

 

Muddy intertidal

 

   

 

Sandy subtidal

 

   

2. What biological aspects of the environment limit where and how organisms live?

A. Competition - organisms that use the same resources eventually subdivide the resource or use it in different ways. Competition is only a factor when the resource is limited.

Direct competition - both organisms use the same resource. Find an example in the book.

 

 

Interference competition - the use of one resource by an organism interferes with another organism's ability to use a different resource. E.g., human-built dams may release enough water for salmon to spawn, but it may be the wrong temperature.

 

B. Predation

Find examples from the book or from organisms we have seen in lab:

A. Shell breakage/Bone damage

 

 

B. Mouthparts

 

 

Indirect evidence

A. Defenses

 

 

 

 

Using predation as evidence of warmbloodedness - how does the predator-prey ratio vary between endothermic and ectothermic organisms?

 

 

 

 

Predation as driving force of natural selection - how did the evolution of shell-crushers change the fauna of the ocean floor from the Paleozoic to the Mesozoic?

 

 

 

 

 

Assessment

1. Background

You should be able to:

2. Physical environment

You should be able to:

3. Biological environment

You should be able to: