Announcements Sept. 29, 2006 Test results are in. Answer Key posted on course web site. You can pick up error sheets after class today.

Exam 1 summary Mean 40.0

A (6) B (6) The “dead zone” in the Gulf of Mexico is caused by: a) Not enough nutrients b) Sharks c) Good farming practices d) Too many nutrients e) Over-fishing

Fertilizer carried into aquatic ecosystems. Increase aquatic plant growth rate. –Lowered oxygen concentrations.

A (9) B (9) A good hypothesis will: a) Be as general as possible b) Be testable and falsifiable c) Be developed in isolation d) Both a and b

A (21) B (21) Mullerian mimicry is when a harmless species is protected because it looks like a poisonous or dangerous species. a) True b) False

Batesian Mimicry: defenseless species (mimic) is protected from predation by its resemblance to a species that is dangerous fly (bee mimic) bumble bee

Mullerian Mimicry: 2 or more distasteful or harmful organisms resemble each other

A (26) B (26) The cowbird is an example of a species native to Illinois that has detrimental impacts on other birds by acting as which of the following: a) Predator b) Mutualist c) Competitor d) Parasite

Nest Parasitism Common Yellow-throat Adult cowbirds don’t build nests Cowbird

A (15) B (15) The field and laboratory experiments designed to investigate deformities in amphibians indicated that: A)Parasites alone could cause the observed deformities B) Chemicals alone could cause the observed deformities C) Chemicals combined with parasites increased the likelihood of deformities D) both a and c E) both b and c However, on form A, answer C) was scored as correct while on form B, D) was scored as the correct answer.

A (15) B (15) The field and laboratory experiments designed to investigate deformities in amphibians indicated that: A)Parasites alone could cause the observed deformities B) Chemicals alone could cause the observed deformities C) Chemicals combined with parasites increased the likelihood of deformities D) both a and c E) both b and c So, if you answered C) or D) for question 15, and it is marked “incorrect” on your score sheet, see us!

A (47) B (47) Amino acids, peptides, and proteins are all essential organic molecules that are composed of: A)Sulfur B)Carbon C)Nitrogen D) Phosphorous Everyone got this question correct (it was not included on the score sheet).

51. (extra credit) The name of your professor is:

51. (extra credit) The name of your professor is: Andy Suarez

Lecture Objectives: 1. Understand both primary and secondary succession 2. Learn the characteristics of the major biomes Types of Ecosystems I & II

Recurring Themes… Terrestrial vs. Aquatic Type of ecosystem influenced by:  rock/soil type  temperature  precipitation  producers/consumers  surrounding ecosystems  time

Succession - communities proceeding through predictable changes through time

Two types of succession  Primary - begins with total lack of organisms, bare mineral surface  Secondary - begins with destruction or disturbance of existing ecosystem Primary takes longer than secondary

Biomes - climax communities with wide geographical distributions Terrestrial biomes primarily influenced by:  Precipitation: total amount per year seasonal distribution form (rain, snow)  Temperature: range of temperatures seasonal patterns  Other factors: soil type, wind, fire, etc.

Precipitation and temperature influenced by latitude, longitude, and altitude

Aquatic Biomes Occupy the largest part of the biosphere  two thirds of the Earth is covered by oceans Marine algae and photosynthetic bacteria produce large portion of world’s oxygen and consume large amounts of CO 2 Differ by salt concentration:  freshwater  saline

Aquatic Biomes Aquatic biomes primarily influenced by:  Light penetration  Type of bottom substrate  Water temperature  Dissolved materials

Pelagic Marine Pelagic - open water environment  Euphotic zone where all photosynthesis occurs Upper layer where suns rays penetrate  Primary producers are phytoplankton Small, microscopic algae and bacteria Nutrient concentration extremely important in determining productivity  Phytoplankton consumed by zooplankton, consumed by crustaceans and fish, consumed by larger fish

Biomes: Pelagic Marine (cont.)

Benthic Marine Benthic - bottom  Several types: coral reefs, mangrove swamps, abyssal  Type determined by substrate, temperature and depth

Benthic Marine  Coral reefs Require shallow, clear, warm water Coral is a sessile animal that excretes a hard, exoskeleton Animals have symbiotic relationship with algae One of most diverse and productive biomes on earth

Benthic Marine  Mangrove swamps Occur in warm, shoreline areas, with low wave action Important nursery area for shrimp, fish

Benthic Marine  Abyssal ecosystem Deep, no light; depend on organic matter from above

Estuary Shallow, partly enclosed area where salinity changes with tides Very productive  Nutrients from rivers  Light penetration Important nursery areas for crustaceans and fish

Freshwater - lakes Three main habitats  Littoral Zone: shallow areas with rooted submergent and emergent plants  Pelagic Zone: deeper areas of open water  Benthic Zone: Bottom

Freshwater - lakes Productivity determined by depth, temperature, nutrients  Oligotrophic lakes = low productivity nutrient poor, often cold and deep  Eutrophic lakes = high productivity nutrient rich, often warm and shallow

Freshwater - lakes Oxygen concentration determines kinds of animals present  Biological oxygen demand = amount of oxygen used by decomposers  As summer progresses in eutrophic lake, oxygen (O 2 ) levels decline

Rivers and Streams Characterized by running water  Attached algae main producer  Many nutrients come from input of terrestrial organic matter  In large rivers, floodplain important source of nutrients, spawning habitat for fish

Biomes: Freshwater – rivers (cont.)

Points to know, 1. What is the difference between primary and secondary succession? What are the steps in the succession process? 2. What factors affect the type of ecosystem that will develop? 3. Know the characteristics of the major terrestrial biomes. 4. Aquatic biomes can be categorized by several axes: 1. Marine, Freshwater, or Estuary 2. Benthic, Pelagic, Littoral 5. What are some differences between lakes/ponds and rivers/streams?