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Marine Ecology Notes
Marine Ecology Ecology: the study of the interactions between organisms and their environment - Abiotic
- Non-living part of the environment
- Example:
- Sediment
- Salinity
- Wave action
- Bottom type
- Biotic
- Living part of the environment
- Marine organisms, like all other organisms, must adapt to the abiotic and biotic conditions of their environment.
- Physiological adaptations
- This refers to how organisms adapt to the environment by changes in metabolism, behavior and other characteristics.
- The genes of the organism remains unchanged
- The adaptation is not passed onto its progeny
- Evolutionary adaptations
- Over generations, species adapt to the environment through natural selection.
- Genetic differences of an individual organism that makes it better adapted to its environment are passed onto the organism’s progeny.
Population Growth - Carrying Capacity is the largest population size that can be sustained by available resources.
- Exponential growth refers to a growth of a population that is rapid and unchecked
- It usually occurs under favorable conditions
- Logistic growth is when the population growth is leveled off due to the limitations on resources, competition and the non-living environment.
- Essentially, rapid population growth occurs until certain factors levels off, or limits, the growth.
- Limiting resources can restrict growth
- Temperature, weather and other non-living conditions can affect population growth
- Competition among organisms affect population growth
Competition - Competition: the interaction that occurs when a resource is in short supply and one organism uses this resource at the expense of another organism.
- Intraspecific competition refers to competition between members of the same species
- Interspecific competition refers to the competition between species.
- In competitive exclusion, one species outcompetes and eliminates another species from the community.
- Normally the dominant species outcompetes an inferior species for a scarce resource. However, determining which species is more dominant depends on conditions such as seasonal variation, habitat features, and physiological adaptations.
- Periodic disturbances can also reduce the population of the more competitive species.
- Some examples of periodic disturbances: harsh weather, landslides, being crushed by rocks.
- Resource partitioning can help species coexist with each other.
- Rather than competitively excluding each other, species can divide or share the resources.
- Examples of resource partitioning:
- Certain species of fish consume different kinds of seaweed.
- Certain types of seabirds that consume the same exact fish may feed at different times, or live at different places.
Competition arises when species compete for a short supply of a resource. The more competitive species survive and reproduce, while the less competitive species do not reproduce as successfully. Over time, a population evolves because of natural selection.
Predator Prey Relationship
Different Types of Selection Concerning Marine Ecology Stabilizing Selection - Selection weeds out the extreme
Disruptive Selection - Selection favors both extremes
Directional selection - One extreme value is selected for
Symbiosis - Symbiosis refers to the close relationship or association between two species
- Three important categories:
- Parasitism
- The symbiont benefits at the expense of the host
- The symbiont harms the host
- Example:
- Viruses are parasites
- Giant tapeworms benefit from the shelter and food in the guts of whales, while the whale is weakened
- Commensalism
- The symbiont benefits, while the host is unaffected
- The host neither benefits, nor is harmed
- Example:
- Barnacles that live on whales benefit with shelter and traveling, while the whale is unaffected
- Mutualism
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