AnnouncementsSept. 29, 2006

Test results are in. Answer Key posted on course web site. You can pick up error sheets after class

today.

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Exam 1 summary

Mean 40.0

A (6) B (6)

The “dead zone” in the Gulf of Mexico is caused by:

a) Not enough nutrientsb) Sharksc) Good farming practicesd) Too many nutrientse) 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 possibleb) Be testable and falsifiablec) Be developed in isolationd) 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) Trueb) 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) Predatorb) Mutualistc) Competitord) 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 deformitiesC) Chemicals combined with parasites increased the

likelihood of deformitiesD) both a and cE) 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 deformitiesC) Chemicals combined with parasites increased the

likelihood of deformitiesD) both a and cE) 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) SulfurB) CarbonC) NitrogenD) 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 succession2. 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 successionPrimary - 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 CO2

Differ by salt concentration: freshwater saline

Aquatic Biomes

Aquatic biomes primarily influenced by:Light penetrationType of bottom substrateWater temperatureDissolved 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 MarineAbyssal ecosystem

Deep, no light; depend on organic matter from above

Estuary Shallow, partly enclosed area

where salinity changes with tides

Very productiveNutrients from riversLight 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 (O2)

levels decline

Rivers and Streams Characterized by running water

Attached algae main producerMany nutrients come from input of terrestrial

organic matterIn 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?