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Chapter 5APES
Things to remember this week
I will check Chapter 5 outlines today
Turn in all sub-work from last week today
Benchmark test on block day will cover Chapters 1-4 and part of 5 (Evolution not on Benchmark!)
Turn in hard copies of Biome project today and electronic copies (Reminder you were specifically told NOT to e-mail the e-copy!!)
Vocab quiz tomorrow!!
Biome presentation
APES Bell work 9/23/13
Farmers in Haiti are being encouraged to plant mango trees because the provisions in the form of fruit are more valuable than the provisions in the form of firewood. A group of Hatian farmers decide to plant mango trees. Magngo saplings cost $10 each. Once the trees become mature, each tree will produce $75 worth of fruit per year. A village of 225 people decides to pool its resources and set up a community mango plantation. Their goal is to generate a per capita income of $300 per year for the entire village.
1. How many mature trees will the village need to meet the goal?
2. Each tree requires 25 m2 of space. How many hectares must the village set aside for the plantation? (1ha=10,000m2)
3. Each tree requires 20L of water per day during the 6 hot months of the year (180 days). The water must be pumped to the plantation from a nearby stream. How many liters of water are needed each year to water the plantation of 900 trees?
Group Work:
In individual groups, look at each slide and determine what it represents
Write your answers down
As a class we will go over each slide and discuss answers
Lower Level Org. Generally Contain More Energy, and Are in Greater Numbers-
Trophic Levels: The Way in Which Energy Moves Thru Systems
Food Web
Resource Partitioning:Each Bird Uses the Tree for Food, However…They Each Divide up Different Portions of the Trunk
Predator/Prey Paired Cycles: One Increases, Causing the Other to Decrease, and Vice Versa
KeyStone Species Keep Ecosystems in Check- Sea Otters are the Keystone Species in This Environment
Species Interactions 5 Major Types of Interactions Among Species
Competition When organisms are seeking same limited resource(s)
Predation When one organism (predator) eats another (prey)
Parasitism One organism benefits, the other is harmed
Herbivory An organism feeds on plant material
Mutualism Both organisms benefit from the relationship
Competition Interspecific:
Among members of 2 or more DIFFERENT species (cardinals and blue jays) If one is more effective
Wipe-out competitor altogether
Through evolutionary time, co-existance is also possible Timing events, slightly different food sources, etc.
RESOURCE PARTITIONING
Intraspecific:
Among member of the SAME species Cardinals
All competition events have a negative impact
Results of interspecific competition
Competitive exclusion = one species completely excludes another species from using the resource
Zebra mussels displaced native mussels in the Great Lakes
Species coexistence = neither species fully excludes the other from resources, so both live side by side
This produces a stable point of equilibrium, with stable population sizes
Species minimize competition by using only a part of the available resource (niche)
Niche: an individual’s ecological role
Fundamental niche = the full niche of a species
Realized niche = the portion of the fundamental niche that is actually filled
Due to competition or other species’ interactions
Resource partitioning Resource partitioning =
species use different resources
Or they use shared resources in different ways
Ex: one species is active at night, another in the day
Ex: one species eats small seeds, another eats large seeds
Character displacement
Character displacement = competing species diverge in their physical characteristics
Due to the evolution of traits best suited to the resources they use
Results from resource partitioning
Birds that eat larger seeds evolve larger bills
Birds that eat smaller seeds evolve smaller bills
Competition is reduced when two species become more different
Predation:
Predator/Prey relationships
Predation can drive population dynamics
Increase in predators will….. Increase in prey will ………
These events can cycle throughout time
Predation can also drive evolution
Stronger adaptations become selected for Defense mechanisms become selected for
Case Study: black and white and spread all over
In 1988, Zebra mussels were accidentally introduced to Lake St. Clair
In discharged ballast water
By 2010, they had invaded 30 states
No natural predators, competitors, or parasites
They cause millions of dollars of damage to property each year
Zebra mussel predation on phytoplankton
Zebra mussels eat phytoplankton and zooplankton
Both populations decrease in lakes with zebra mussels
Zebra mussels don’t eat cyanobacteria
Population increases in lakes with zebra mussels
Zebra mussels are becoming prey for some North American predators:
Diving ducks, muskrats, crayfish, flounder, sturgeon, eels, carp, and freshwater drum
Defenses against being eaten
Parasites Relationships in which 1 organism depends on another, while doing harm
USUALLY does not result in death. Why not?
Most live inside their host
Disease pathogens (ex; protist that causes malaria) Animals (tapeworms)
Some live externally
Lamprey
Parasitoids
Eggs are laid on the backs of others, when they hatch, use host as food source
Co-evolution
Parasites will adapt and evolve with changes in host
Evolutionary Arms Race Host changes in order to adapt to parasite pressures
Parasites will change in order to adapt to host pressures
Herbivore When animals feed on the tissues of plants
Insects are most wide-spread Doesn’t usually kill plant, but can affect growth
and reproduction
Plants have also evolved to defend themselves
Chemically Arm themselves w/thorns, spines, or hairs Critter usually evolves as well, tho
Evolutionary Arms Race
Mutualist Interacting species benefit from one another
Each provides a service or resource the other needs Symbiosis: two organisms live in close physical contact
Not always the case however;
Pollination; physical contact may only happen once
Commensalism One species benefits from relationship while the other is
neither harmed nor benefits
Cattle Egret: benefits from cattle stirring up insects, cow is neither harmed nor really benefits
Amensalistic: hard to prove- One organism harms or inhibits another while remaining unaffected itself;
Fungus Penicillium notatum which produces penicillin- the penicillin inhibits growth of bacteria, but it appears that the Penicillium is unaffected
Otter video clip
Sea otter impact on urchins
Otters substantially reduce populations of large urchins. Estes and Palmisano (Science 1974)
Roles are NOT the same
Keystone Species: species with strong or wide-reaching impact far out of proportion to its abundance
Removal of this species will have substantial ripple effects Can alter large portions of food webs
Usually large-bodied 2nd ary or tertiary consumers near the top of food chain
Controls herbivores, who if left unchecked can devastate ecosystems
Kelp density and otters
0 3 7 11 15 19
0 3 7 11 15 19
0 3 7 11 15 19
0 3 7 11 15 19
100
60
20
100
60
20
Some organisms play big roles
Initial Keystone Species Concept
The idea was developed in 1969 by Dr. Robert Paine during his time at the University of Washington as a zoology professor. The idea also originated from his work with the Makah Indian Tribe and lands along Washington’s Pacific coastline.
Initial Keystone Species Concept
A keystone species is a species whose whose impact on its community or ecosystem are larger and greater than would be expected from its relative abundance or total biomass in the environment.
Originally, keystone species were characterized as a predator species that feed preferentially on the dominant competitor among its prey species, preventing the dominant prey from excluding other species.
The presence of keystone species maintain higher species diversity in ecosystems than if keystone species were absent.
Predator-prey interactions
Example: Pisaster ochraceus and the mussel Mytilus californianus
Bob Paine’s Caging experiments
Follow-up (14-17 yrs)
Comparisons to Chile and New Zealand studies
Bob Paine’s experiments:Effects of Pisaster removal
Castro and Huber, Fig. 11.22
Bob Paine’s experiments:Effects of Pisaster removal
What happened when he returned to his study site 14-17 years after cages were removed?
How do Bob Paine’s results compare to similar studies in New Zealand and Chili?
Fig. 6.18: Pisaster ochraceus as a Keystone
species
Fig. 6.19: Natural experiments on New England coast (Menge and Lubchenco)
Role of grazers Limitation of algae by
grazers
Overview
Case study: Katharina tunicata
Role of grazers Maintenance of diversity by grazers
Example: Effects of snails on algal diversity in a tidepool.
Keystone Species Concept Since 1969, non-predator
keystone species have been identified and studied, such as beavers (Castor canadensis), bison (Bison bison), kangaroo rats (Dipodymys spp.), and plant species such as the quaking aspen (Populus tremuloides).
Salmon as a Keystone Species-Salmon play a vital role in their ecosystems-They help support approximately 137 different species
-41 mammals-89 birds-5 reptiles-2 different amphibians
Without salmon as a keystone species, we could see a tremendous decrease in dependent creatures.
Example of Salmons importance
-In 1981, at McDonald Creek, more than 600 bald eagles gathered to feed on Kokanee salmon carcasses. When a non-native shrimp was introduced in an adjacent lake, the shrimp competed with the salmon for zooplankton - the salmon run lost.
-In 1989, only 25 eagles were found at McDonald Creek.
-The loss of salmon caused what is called an "ecosystem collapse."
Northwest species now struggling because of depleted salmon runs include the following:
Black Bear
Bald Eagle
Grizzly Bear
Caspian tern
Harlequin duck
Osprey
…Dependent species continued
Orca
Sea lion
River Otters
Canis lupus
Traditionally had the largest range of any terrestrial mammal
Extirpated from U.S. by farmers, settlers and hunters in the early 20th century
After 60 years Wolves are necessary
components of their ecosystems
Why? Controls elk populations Increased elk browse negatively
effects growth of seedlings along riparian areas
Decreased growth of riparian vegetation causes river bank erosion and widening
This has negative effects on salmon and other aquatic life, and increases flooding and nutrient loss from the soil
The controversy concluding predatory keystone species
Wolves are beautiful creatures until they start killing your livestock or pets
Do you want really want to meet him when you are out on a hike?
• Also too many wolves would put stress on prey species such as elk and deer.
Species can change communities
Trophic Cascade = predators at high trophic levels indirectly affect populations at low trophic levels
By keeping species at intermediate trophic levels in check
Extermination of wolves led to increased deer populations, which overgrazed vegetation and changed forest structure
Ecosystem engineers = physically modify the environment
Beaver dams, prairie dogs, ants, zebra mussels