Interactions among animals and the environment

1
Ecological Principles

• Interactions among animals and the environment

2
What is Ecology?

• A combination of biotic and abiotic factors

Biotic Predator-prey interactions Symbiotic
relationships Competition Species interactions
Abiotic Salinity Temperature Pressure Non-biologic
al factors
In the real world these factors are not easily
separated
3
Key Ecology Terms

• Species natural group of interbreeding
  individuals, which are reproductively isolated
  from other groups
• Population all the species in a given area
• Community several populations, which occur in an
  area
• Ecosystem a series of communities and the
  surrounding environment

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How Populations Grow

• Resources
• Carrying capacity
• Limiting resource
• Self-regulating

5
Competition

• Competition refers to the interaction between
  organisms for a necessary and limiting resource
• Intraspecific
• Interspecific

Barnacle and mussels compete for space
6
The Results of Competition

• Natural selection production of offspring by the
  best-adapted individuals in a population
• Evolution a change in the genetic makeup of a
  population
• To be successful a species must find the right
  balance between specialization and generalization
• Niche the role a species plays in the community

7
Predation

• Predation is the act of one animal eating another
• Coevolution - the predator evolving in response
  to adaptations of the prey, or vice versa

8
Living Together

• Symbiosis
• Commensalism
• Mutualism
• Parasitism
• Ectoparasites
• Endoparasites

9
Flow of Energy

• Autotrophic organisms which capture energy to
  make organic matter
• Producers
• Heterotrophic organisms that capture energy by
  eating
• Herbivores - eat strictly producers
• Carnivores or piscivores - eat meat or fish
• Omnivores - generalists
• Apex predators - top predators

10
Trophic Structure
11
Sandy Shoreline Community

• Soft bottom communities are found in areas where
  sediment has accumulated
• Dominate the east coast of the U.S and the gulf
  coast
• Due to the environmental conditions most animals
  bury themselves in the substrate.

12
Environmental Conditions

• Wave action is the most important physical factor
  and correlates directly with beach slope and
  grain size

13
Living in the Sediment

• Aerobic Respiration
• Anaerobic Respiration
• Hydrogen sulfide (H2S)
• Anoxic

14
Sandy Beach Zonation
15
Fauna Composition

• Noticeably absent are the plants, due to lack of
  stable substrate
• Crustaceans, bivalves, and polychetes dominate
  sandy beaches
• Predators?
• Feeding strategies?

16
Sandy Beach Food Web
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Mole Crabs
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Locomotion

• Bivalves use a muscular foot for locomotion
• Mole crabs and other arthropods use appendages
  for burrowing
• Sea cucumbers and worms both feed and burrow at
  the same time

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Meiofauna