January 31st 2019 Notes

Class notes

Tropical Marine Biology

January 31st

Types of consumers


  • Feed directly on photosynthetic producers
  • Feed on Producers/ Also called herbivore
  • (Zooplankton, Sea urchins, fishes, insects)


  • Feed on primary consumer
  • Frogs, Rats , Spiders , some fish ,


  • Sometimes called “Top Carnivores”
  • Snakes , Hawks , Large fish , sharks

^ Together these constitute a Food chain

Each level is called a trophic level


Does Not tend to go past it but why?

  • Around 90% of energy is lost between

In a grassfield you have 100000 Kcal of energy

  • After producers make 10,000 kcal
  • Primary consumers 1,000 kcal
  • Secondary consumers 100 kcal
  • Tertiary consumers 10 kcal

Trophic transfer of energy is lost via cellular respiration

  1. Grain —-> Humans
  2. Grian —> beef —-> Humans

     – Which one would give humans more power?

being vegetarians would give humans the most use of the energy potential from foods

In Aquatic

Marine food Pyramid

Anything that dies become Detritus in the ocean

  • Detritus is dead organic matter – dead bodies of animals, plants, fungi, etc.
  • Includes animal wastes, secretions
  • Animal detritivores are called scavengers


  • Microbial detritivores are often called decomposers.
  • Bacteria
  • Fungi
  • – Secrete enzymes onto detritus, breakdown molecules , release Co2, and heat
  • Larger detritivores (worms, etc.) break down material into smaller fragments. (Fragmentation)
  • Bacteria and fungi secrete enzymes onto detritus, breakdown molecules by converting large organic macromolecules into small soluble compounds and inorganic macromolecules into small soluble compounds and inorganic nutrients ( nitrates, nitrites, phosphates, etc.) This phase is also known as mineralization
  • The small molecules are released into the soil, then taken up by plants (nutrient uptake)  
  • This process releases Co2 and heat
  • Decomposition

Trophic levels are never simple they are always layered


Dead leaves – Keep darker streams in the woods alive from dying trees (freshwater example)

Keystone Species

  1. a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

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