Download 14_Ecosystems2

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
60
50
40
30
20
10
0
20
25
30
35
40
Mean 40.0
45
50
A (6) B (6)
The “dead zone” in the Gulf of Mexico is caused by:
a)
b)
c)
d)
e)
Not enough nutrients
Sharks
Good farming practices
Too many nutrients
Over-fishing
•Fertilizer carried into
aquatic ecosystems.
•Increase aquatic
plant growth rate.
–Lowered oxygen
concentrations.
A (9) B (9)
A good hypothesis will:
a)
b)
c)
d)
Be as general as possible
Be testable and falsifiable
Be developed in isolation
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
Adult cowbirds don’t build nests
Cowbird
Common
Yellow-throat
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)
B)
C)
D)
Sulfur
Carbon
Nitrogen
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:
Types of Ecosystems I & II
1. Understand both primary and secondary
succession
2. Learn the characteristics of the major
biomes
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 CO2

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

Upper layer where suns rays penetrate
 Primary


zone where all photosynthesis occurs
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
Bottom
Zone:
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
Attached
by running water
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.
2.
3.
4.
What is the difference between primary and secondary succession?
What are the steps in the succession process?
What factors affect the type of ecosystem that will develop?
Know the characteristics of the major terrestrial biomes.
Aquatic biomes can be categorized by several axes:
Marine, Freshwater, or Estuary
2. Benthic, Pelagic, Littoral
1.
5.
What are some differences between lakes/ponds and
rivers/streams?