Ecology

Chapters 19,21,22

What is Ecology? study of interactions between organisms and

their living and nonliving environment collect information on organisms and

environment to discover and explain patterns

What are Ecological Issues? man has changed environment drastically

how do we improve it? Ozone layer- absorbs UV light (protects

organisms) Chlorofluorocarbons (CFC’s) chemicals destroying the

ozone ozone depleting over Antarctica New evidence has shown improvement

Climatic changes Greenhouse effect- warming of Earth because of

insulating effect of the gases on the atmosphere. (EX. CO2 and H2O vapor)

caused by burning of fossil fuels (coal, oil, natural gas)

What are the Ecological Levels of Organization?

Biosphere The entire planet- including all life on Earth and all parts of

the Earth’s land, water, and atmosphere Biome

A group of ecosystems that share similar climates and types of organisms

Ecosystem all the organisms and the nonliving environment found

in a particular place pond - amount of dissolved O2 and CO2, pH, amount of

nitrogen and sunlight, temperature, pollutants ecosystem is a network where all organisms are linked to

other organisms and to the nonliving environment Interdependence-any disturbance or change in ecosystem

can interfere with interactions and affect whole ecosystem

What are the Ecological Levels of Organization? community - all the interacting organisms of

an area pond - fish, turtles, frogs, algae, plants, bacteria,

insects look at how species interact and how interactions

affect community population - all the members of a species

that live in one place at one time that can interbreed

organism - a single member of a species

What are biotic and abiotic factors? Biotic factors

living components of environment all organisms- animals, plants, bacteria, and

fungus Abiotic Factors- nonliving components of

environment (physical and chemical) temperature, humidity, pH, salinity, oxygen

concentration, amount of sunlight, availability of nitrogen, precipitation, soil

Niche vs. Habitat Niche

way of life or role a species plays in its environment

range of conditions it can tolerate how it obtains needed resources

(scavenger, herbivore, etc.) time of reproduction, number of offspring when it is active

Habitat where an organism lives - forest, pond,

rotting log, field

What conditions can an organism tolerate? Tolerance:

organisms ability to survive and reproduce in wide range of environmental conditions

individual organisms adapted to function in specific range of conditions

Tolerance Curve:

Responses to changing conditions acclimation - adjustment of tolerance to abiotic factors

high elevation - more RBC’s conformers - do not regulate internal conditions

change as external environment changes internal cond. remain in optimal range only as long as environ.

cond. remain in that range (snake temp.) regulators - use energy to control some internal cond.

can keep internal cond. within optimal range over wide range of environmental cond. (our body temp.)

unsuitable conditions (escape) desert animals go underground or in shade during day - active at

night dormancy - state of reduced activity in unfavorable cond.

(reptiles and amphibians in winter) migration - move to more favorable habitat (birds)

What is symbiosis? relationships between species living in close

association with one another

What are the five primary ways that organisms depend on each other? five main classes of symbiotic relationships in nature:

1. mutualism 2. parasitism 3. commensalism 4. predation 5. competition.

Mutalistic Relationships The sea anemone’s sting has two functions: to capture

prey and to protect the anemone from predators. Even so, certain fish manage to snack on anemone tentacles.

The clownfish, however, is immune to anemone stings. When threatened by a predator, clownfish seek shelter by snuggling deep into an anemone’s tentacles.

Mutalistic Relationship If an anemone-eating species tries to attack the

anemone, the clownfish dart out and chase away the predators.

This kind of relationship between species in which both benefit is known as mutualism.

Parasitic Relationship

Tapeworms live in the intestines of mammals, where they absorb large amounts of their hosts’ food. (endoparasites)

Fleas, ticks, lice, and the leech shown, live on the bodies of mammals and feed on their blood and skin. (ectoparasites)

These are examples of parasitism, relationships in which one organism lives inside or on another organism and harms it.

The parasite obtains all or part of its nutritional needs from the host organism. parasites weaken the host but do not kill it

Commensalism Barnacles often attach themselves to a whale’s skin.

They perform no known service to the whale, nor do they harm it. Yet the barnacles benefit from the constant movement of water—that is full of food particles—past the swimming whale.

This is an example of commensalism, a relationship in which one organism benefits and the other is neither helped nor harmed.

Predator- Prey Relationship organism that captures, kills, and eats

another (the prey) Advantages of Predator:

1) good sense of smell and/or eyesight2) web of spiders 3) heat-sensitive pit of rattlesnakes4) sharp teeth (wolves, sharks), talons

(hawks, owls)5) tiger’s stripes (camouflage)6) speed (cheetah, shark)7) climbing ability (to get to a nest)

Predator- Prey Relationship Advantage of Prey:

1) ability to flee quickly 2) hiding/camouflage 3) resemble inedible object 4) bright, warning colors 5) resembling other organisms 6) spines, thorns, foul odor

mimicry - harmless species resembles a poisonous or distasteful one two or more dangerous or distasteful look similar (many bees

and wasps) - all benefit, predator encountering one avoids similar ones

herbivore-plant plant defenses - thorns, spines, sticky hairs, tough leave chem. defense - poisonous, irritating, bad-taste medical use - morphine, atropine, codeine, taxol, quinine

Competitive Relationship use of same limited resource by 2 or more

species Competitive exclusion - one species in

community eliminated due to competition for same resource one uses it more efficiently and has a reproductive

advantage

Think???? In 1883, the volcanic island of Krakatau in the Indian

Ocean was blown to pieces by an eruption. The tiny island that remained was completely barren.

Within two years, grasses were growing. Fourteen years later, there were 49 plant species, along with lizards, birds, bats, and insects. By 1929, a forest containing 300 plant species had grown. Today, the island is blanketed by mature rain forest.

How did the island ecosystem recover so quickly?

Primary and Secondary Succession Ecological succession is a series of more-or-less

predictable changes that occur in a community over time.

Ecosystems change over time, especially after disturbances, as some species die out and new species move in.

Over the course of succession, the number of different species present typically increases.

Primary Succession What can cause Primary Succession?

Volcanic explosions can create new land or sterilize existing areas.

Retreating glaciers can have the same effect, leaving only exposed bare rock behind them.

Succession that begins in an area with no remnants of an older community is called primary succession.

Example of Primary Succession For example, in Glacier Bay, Alaska a retreating

glacier exposed barren rock. Over the course of more than 100 years, a series of

changes has led to the hemlock and spruce forest currently found in the area.

Changes in this community will continue for centuries.

Primary Succession The first species to colonize barren areas are called

pioneer species. One ecological pioneer that grows on bare rock is

lichen—a mutualistic symbiosis between a fungus and an alga.

Secondary Succession Causes of Secondary Succession

Wildfire, hurricane, or other natural disturbance. Can also follow human activities like logging and farming.

Advantage to disasters: many species are adapted to them. Although forest fires kill some trees, for example, other trees

are spared, and fire can stimulate their seeds to germinate.

Secondary Succession Sometimes, existing communities are not completely

destroyed by disturbances called secondary succession.

Secondary succession proceeds faster than primary succession, because soil survives the disturbance. As a result, new and surviving vegetation can regrow rapidly.

Secondary Succession Example of secondary succession taking place in

abandoned fields of the Carolinas’ Piedmont. Over the last century, these fields have passed

through several stages and matured into oak forests. Changes will continue for years to come.

Climax Community

Stable end point reached after predictable series of changes

organisms of each stage alter physical environment that can prevent their survival but encourages organisms of next succeeding stage

Recent studies, however, have shown that succession doesn’t always follow the same path, and that climax communities are not always uniform and stable.

Answer to Succession Question: On both Mount Saint Helens and Krakatau, primary

succession proceeded through predictable stages.

The first plants and animals that arrived had seeds, spores, or adult stages that traveled over long distances.

Hardy pioneer species helped stabilize loose volcanic debris, enabling later species to take hold.

Historical studies in Krakatau and ongoing studies on Mount Saint Helens confirm that early stages of primary succession are slow, and that chance can play a large role in determining which species colonize at different times.

Primary Producers (Autotrophs) Capture energy to make own food

Photosynthesis – using the sun’s energy

Chemosynthesis- use energy from inorganic molecules

Primary Producers (Autotrophs) Store energy in forms available to other organisms

that eat them, and are therefore essential to the flow of energy through the biosphere.

For example, plants obtain energy from sunlight and turn it into nutrients that can be eaten and used for energy by animals such as a caterpillar.

Who are Primary Producers? Plants , Algae, some Protists Photosynthetic bacteria, most commonly cyanobacteria

Think????? What happens to energy stored in body tissues when one

organism eats another?

Energy moves from the “eaten” to the “eater.” Where it goes from there depends on who eats whom!

Consumers (Heterotrophs) Consume organic molecules made by other

organisms Who are consumers?

Animals, most protists, fungi, many bacteria Types:

herbivore - eat producers carnivore - eats other consumers

include snakes, dogs, cats, and a giant river otter. omnivore - eats both producers and consumers scavenger - feeds on remaining dead organic matter

king vulture, are animals that consume the carcasses of other animals that have been killed by predators or have died of other causes.

decomposers - cause decay by breaking down complex molecules in dead organic matter (recycle nutrients) bacteria and fungi

How does energy Flow? trophic level - an organism’s position in the

sequence of energy transfers energy flows from producers to consumers

food chain - transfer of energy through a single series of organisms

hawk (tertiary consumer) 4th trophic level (3rd order consumer) snake (secondary consumer) 3rd trophic level (2nd order consumer) mouse (primary consumer) 2nd trophic level (1st order consumer) grass (primary producer) 1st trophic level

How does energy Flow? food web - series of interrelated food chains

(p. 418) many consumers eat more than one type of food several species may feed on same organism

Explain happens to the food web if the krill population decreases?

How productive are Producers? primary productivity - rate at which producers

capture energy in an ecosystem (Carrying capacity) some sugar used for respiration, maintenance and

repair some used to make new organic material (growth,

reproduction) biomass - the living organic material in an

ecosystem only the energy in biomass is available to other

organisms the amount of biomass in a trophic level is determined by the

amount of energy available.

Pyramids

Ecological pyramids- show the relative amount of energy or matter contained within

each trophic level in a food chain or food web. A small portion of the energy that passes through any

trophic level is ultimately stored in the bodies of organisms at the next level. Organisms expend much of the energy they acquire on

life processes: such as respiration, movement, growth, and reproduction.

Most of the remaining energy is released into the environment as heat; a byproduct of these activities.

Energy Pyramid- 10% Rule On average, about 10 percent of the energy

available within one trophic level is transferred to the next trophic level.

The more levels that exist between a producer and a consumer, the smaller the percentage of the original energy from producers that is available to that consumer.

Ecosystem Recycling biogeochemical cycle - substances move from

abiotic environment to biotic and back again How?

Water Cycle Carbon Cycle Nitrogen Cycle

Water Cycle Evaporation - water molecules evaporate from the ocean

or other bodies of water to form water vapor). Transpiration- evaporation of water from

stomata in plant leaves Precipitation- water vapor condenses into tiny

droplets that form clouds. Those droplets become large enough, fall in the form of

rain, snow, sleet, or hail.

Carbon Cycle CO2 used in P.S. - plants make carbohydrates

from it respiration releases CO2 decomposers release CO2 when they break

down organic compounds burning fossil fuels also releases CO2, as does

burning of rain forest

Nitrogen Cycle All organism need N to make amino acids- to build proteins

and nucleic acids 78% of atmosphere is nitrogen gas (not usable) nitrogen fixation - converting N2 to ammonia (NH3)

nitrogen-fixing bacteria live in soil and in roots of legumes (beans, peas, clover, alfalfa)

mutualism (plant provides home and sugar, bacteria supplies nitrogen)

Ammonification - decomposers break down dung, urine, dead bodies and release nitrogen as NH3

nitrification - soil bacteria oxidize ammonia to nitrites (NO2) and nitrates (NO3) - plants use nitrates to form amino acids

denitrification - anaerobic bacteria convert nitrates to N2

Nitrogen Cycle