Large Marine Ecosystems of the world Show video on Marine Ecosystems:

Review of Food Chains and Food Webs Food chains and food webs model the flow of energy in an ecosystem. Trophic level is the feeding level or position an organism is in a food chain or food web, NOT A ENERGY LEVEL. The position on the food web is usually an indication of what trophic level it lays on.

Trophic Levels Trophic level – feeding level within a food chain/web Arrows represent flow of energy and BIOMASS Biomass: is the mass of organisms present in a defined area or volume / It is distinguished by productivity - the amount of living material produced per unit area per time Effects of top predators and producers: Top-down effects: the strong effect of top predators Too many predators – consume of prey Too many predators – prey retreat to shelter Bottom-up effects: changes in lower trophic levels that exert strong effects on ecosystems Increase in phytoplankton productivity – greater food input at the lower levels which indirectly allow larger populations of top predators to exist.

What is a Whale Fall? When a whale dies, the carcass sinks to the sea floor…this is known as a “whale fall” / How is the energy from its carcass absorbed?? The video below shows the gradual change in the community structure over time Feast in the Deep Boneworms on Dead Whales in Monterey Bay

Types of Interrelationships Interactions between species are categorized at the level where one population interacts with another. Symbiosis Mutualism Commensalism Parasitism Competition Predation Predator versus Prey

Symbiosis - MUTUALISM The relationship between 2 different organisms, where BOTH derive some benefit from the relationship Examples Corals and zooxanthellae Cleaner fish and grouper Chemosynthetic bacteria and tubeworms

Mutualism In mutualism, both organisms benefit from one another. For example: A clownfish and a sea anemone have a mutualistic relationship. The fish is protected by the anemone and the anemone receives scraps of food from the clownfish.

Commensalism In commensalism, one organism benefits from the other. The other organism is neither helped nor harmed. This is usually a relationship between a small organism and a larger organism where the smaller organism benefits. The benefit is usually shelter, transportation, defense, or food. An example is the relationship of the remora and the shark. The remora receives food in the form of scraps that come from the shark, but the shark is unaffected.

Parasitism Relationship between organisms where 1 organisms benefits at the expense of the other (the host) Parasites obtain nutrients from host Ectoparasites Live on OUTSIDE of the host Example: Fish lice Endoparasites Live INSIDE host (digestive system, attached to gills, muscle tissue) Example: nematodes (roundworms) living in fish

Summary of Symbiotic Relationships Relationship Organism 1 Organism 2 Mutualism Commensalism Parasitism

Competition Competition - both species (or individuals) attempt to use the same limited resource such that both are negatively affected by the relationship. Indirect competitors use the same resource but do not come into contact with each other (day/night) Direct competitors use the same resource but do come into contact with each other

Adaptations to Competition When two species with similar niches are placed together in the same ecosystem, we might expect one species to be more successful than the other. But in the course of evolution, adaptations that decrease competition will also be advantageous for species whose niches overlap. One way competition can be reduced between species is by dividing up the niche in time or space.

Predation In predation, one organism, the predator, kills and eats another, the prey. The relationship of predator and prey is essential to keeping populations of both animals at normal levels.

Predator-Prey Relationship Factors which affect # of predators in an ecosystem Availability of food As the # of prey increases the # of predators increases As the # of prey decrease the # of predators decrease What would a graph of this relationship look like? With a partner create a graph? Be prepared to explain your graph!

Predator-Prey Graph

Types of Species Interactions

Which relationship is it? An American Robin builds a nest in a Red Maple tree

Which relationship is it? A tick makes its home on a White-tailed Deer

Which relationship is it? A Nile crocodile will open its mouth and allow the Egyptian plover to feed on any leeches that are attached to its gums

Which relationship is it? A Red Fox hunts and consumes a Black Rat Snake

Which relationship is it? A certain type of paramecium engulfs unicellular green algae into vacuoles within its cell. The algae are allowed to utilize carbon dioxide produced by the paramecium and the paramecium is able to utilize food produced by the algae