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