Chapter 37 Communities and Ecosystems Power Point Lectures

COMMUNITY ECOLOGY § An organism’s biotic environment includes § Other individuals in its own

Biology and Society: Does Biodiversity Matter? • The expanding human population threatens – Biodiversity

• Two recent victims of human-caused extinctions are – Chinese river dolphins –

Habitat destruction © 2010 Pearson Education, Inc.

Invasive species © 2010 Pearson Education, Inc.

Overexplotation © 2010 Pearson Education, Inc.

Golden toads in Costa Rica have not been since 1989 Figure 20. 2 b

• Coral reefs are rich in species diversity, yet – An estimated 20%

Genetic diversity: Einkorn wheat, one of the wild relatives of modern cultivated varieties Figure

Causes of Declining Biodiversity • Ecologists have identified four main factors responsible for the

Habitat Destruction • Biodiversity is threatened by the destruction and fragmentation of habitats by

Overexploitation • People have overexploited wildlife by harvesting at rates that exceed the ability

Bluefin tuna ready for sale Figure 20. 5

Competition among species 1. Interspecific competition between 2 closely related species • Usually only

Competitive exclusion. Two species of Paramecium, P. caudatum and P. aurelia, both feed on

Interspecific competition © 2010 Pearson Education, Inc.

Interspecific competition among scavengersgolden eagle and a red fox fight over a moose carcass

Competition among species 2. Mutualism- interaction between two species that is benefical to both

Mutualism between anemone fish and sea anemone. Each species provides protection for the other.

Mutualism © 2010 Pearson Education, Inc.

Commensalism © 2010 Pearson Education, Inc. Fig. 17 -3 a, p. 342

Competition among species 3. Predation- one organism feeds on parts or all of a

Predator- prey © 2010 Pearson Education, Inc.

Predatory frog fish uses a fake lure to catch its prey © 2010 Pearson

Defense mechanisms for prey • Numerous adaptations for predator avoidance have evolved in prey

Camouflage- desert plants resemble stones and hide among them © 2010 Pearson Education, Inc.

• Some insects have elaborate disguises that make them resemble – Twigs –

b. warning coloration – Brightly colored pattern – Way to warn predators that an

Warning coloration © 2010 Pearson Education, Inc.

Warning coloration © 2010 Pearson Education, Inc. Fig. 17 -6 c, p. 344

c. Mimicry is a form of defense in which one animal looks like another

Mimicry between clearwing moth and yellow jacket wasp © 2010 Pearson Education, Inc.

Mimicry between 2 species of S. American butterflies that share the characteristic of tasting

• Herbivory is the consumption of plant parts or algae by an animal.

Spines/ thorns © 2010 Pearson Education, Inc.

The cinnabar moth caterpillar feeds solely on tansy ragwort, which is poisonous for animals

Peppermint Cinnamon Cloves Figure 20. 14

Competition among species 4. Parasitism- predator feeds on the prey with out killing it

© 2010 Pearson Education, Inc. Fig. 17 -8 b, p. 346

Trophic Structure • Trophic levels- position of level of organization among a food chain

Trophic levels § Food chain-transfer of energy from autotroph to heterotroph through a process

• The trophic level that supports all other trophic levels consists of autotrophs,

• All organisms in trophic levels above the producers are consumersheterotrophs that feed

• above the level of primary consumers are carnivores- eat animals • eat

Producers Plant A terrestrial food chain Phytoplankton An aquatic food chain Figure 20. 15

Primary consumers Zooplankton Herbivore Producers Plant A terrestrial food chain Phytoplankton An aquatic food

Secondary consumers Carnivore Primary consumers Zooplankton Herbivore Producers Plant A terrestrial food chain Phytoplankton

Tertiary consumers Carnivore Secondary consumers Carnivore Primary consumers Zooplankton Herbivore Producers Plant A terrestrial

Quaternary consumers Carnivore Tertiary consumers Carnivore Secondary consumers Carnivore Primary consumers Zooplankton Herbivore Producers

• Detritivores- scavengers that consume detritus- the dead material left by all organisms

Biological Magnification • Environmental toxins accumulate in consumers at higher concentrations up a trophic

Increasing concentrations of PCBs Herring gull eggs 124 ppm Lake trout 4. 83 ppm

Food Webs • Few ecosystems are as a simple as an unbranched food chain.

37. 10 Species diversity includes relative abundance and species richness § Species diversity defined

37. 11 Keystone species have a disproportionate impact on diversity § Keystone species –

Keystone absent © 2010 Pearson Education, Inc.

Pisaster sea star, a keystone species, eating a mussel. © 2010 Pearson Education, Inc.

Ecological Succession • ecological succession- a gradual replacement of one species by other species

Ecological succession § Pioneer community- 1 st community in succession § Serel stage- successive

Annual Perennial plants and grasses Shrubs Softwood trees Hardwood such as pines trees Time

© 2010 Pearson Education, Inc. Fig. 17 -9, p. 347

2. Secondary succession- habitat has been disturbed but life remains • Examples of secondary

Ecological succession after a fire © 2010 Pearson Education, Inc. Figure 20. 24

Example of ecological succession. (A) Mount Saint Helens erupted in 1980. Volcanic ash completely

ECOSYSTEM ECOLOGY • ecosystem- community of organisms interacting with one another and their physical

• A simple terrarium is a microcosm that exhibits the two major processes

Chemical cycling Energy flow Chemical energy Light energy Heat energy Chemical elements Bacteria and

• Energy flows through ecosystems. • Chemicals are recycled within and between ecosystems.

Producer Energy flow Chemical cycling © 2010 Pearson Education, Inc. Herbivore (primary consumer) Decomposers

Energy Flow in Ecosystems • All organisms require energy for – Growth – Maintenance

Ecological Pyramids • When energy flows as organic matter through the trophic levels of

Plant material eaten by caterpillar 100 kilocalories (kcal) 35 kcal 50 kcal Feces Cellular

• A pyramid of production illustrates the cumulative loss of energy with each

Tertiary consumers 10 kcal Secondary consumers 100 kcal Primary consumers Producers 1, 000 kcal

• The energy available to top-level consumers is small compared to the energy

Human Resource Use • The dynamics of energy flow apply to the human population

• The two energy pyramids that follow compare the amount of food available

Trophic level Secondary consumers Human meat-eaters Human Primary consumers vegetarians Producers © 2010 Pearson

animation § Energy flow © 2010 Pearson Education, Inc.

Concept Check §The caterpillar is a primary consumer in a food chain. How much

Answer §The caterpillar is a primary consumer in a food chain. How much of

Chemical Cycling in Ecosystems • Life depends on the recycling of chemicals. – Nutrients

The General Scheme of Chemical Cycling • Biogeochemical cycles involve – Biotic components –

Consumers 3 2 Producers Decomposers 1 Nutrients available to producers Abiotic reservoir Geologic processes

important biogeochemical cycles 1. Carbon 2. Phosphorus 3. Nitrogen © 2010 Pearson Education, Inc.

1. The Carbon Cycle • The cycling of carbon between the biotic and abiotic

CO 2 in atmosphere 5 Burning 3 Cellular respiration Photosynthesis 1 Wood and fossil

animation § Carbon cycle © 2010 Pearson Education, Inc.

2. phosphorus cycle § Organisms require phosphorus for nucleic acids, phospholipids, and ATP a.

6 Uplifting of rock 3 Weathering of rock Runoff Phosphates in rock Animals Plants

2. The Nitrogen Cycle • Nitrogen is – An ingredient of proteins and nucleic

• nitrogen fixation converts gaseous N 2 to ammonia and nitrates, which can

Nitrogen (N 2) in atmosphere 8 Animal Plant 6 Assimilation by plants Organic compounds

Nutrient Pollution • The growth of algae and cyanobacteria in aquatic ecosystems is limited

Algal growth as a result of phosphate pollution Figure 20. 35

• Nitrogen runoff from Midwestern farm fields has been linked to an annual

Mississippi River Gu f. M lf o exico Light blue lines represent rivers draining

animation § Nitrogen cycle © 2010 Pearson Education, Inc.

Concept Check §Matter that makes up life is recycled and reused. Which of the

Answer §Matter that makes up life is recycled and reused. Which of the following

Thinking Like a Scientist §This figure plots the loss of nitrate from a deforested

Answer §This figure plots the loss of nitrate from a deforested watershed on the

Thinking Like a Scientist §How long after tree cutting did it take for the

Answer §How long after tree cutting did it take for the nitrate levels to

Thinking Like a Scientist §Snow is a source of nitrate. Based on this plot

Answer §Snow is a source of nitrate. Based on this plot during what season

Biome § Major biomes of north america 1. Desert 2. Grasslands 3. Deciduous forests

Deserts © 2010 Pearson Education, Inc. Fig. 18 -5 a, p. 365

Grasslands © 2010 Pearson Education, Inc. Fig. 18 -5 b, p. 365

© 2010 Pearson Education, Inc. Fig. 18 -6, p. 366

Coniferous forests © 2010 Pearson Education, Inc. Fig. 18 -7, p. 366

© 2010 Pearson Education, Inc. Fig. 18 -8, p. 367

Science and Society §During the summer of 2003 the entire western U. S. seemed

Science and Society §Travelers into and out of our country are asked about agricultural

Science and Society §The tall grass prairies of eastern Kansas are the largest remaining

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Chapter 37 Communities and Ecosystems Power. Point Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Lecture by Brian R. Shmaefsky Copyright © 2009 Pearson Education, Inc.

COMMUNITY ECOLOGY § An organism’s biotic environment includes § Other individuals in its own population § Populations of other species living in the same area § Species living close enough together for potential interaction is called a community.

Golden toads in Costa Rica have not been since 1989 Figure 20. 2 b

• Coral reefs are rich in species diversity, yet – An estimated 20% of the world’s coral reefs have been destroyed by human activities – 24% are in imminent danger of collapse – Another 26% of coral reefs may succumb in the next few decades if they are not protected Video: Coral Reef © 2010 Pearson Education, Inc.

Figure 20. 3

Genetic diversity: Einkorn wheat, one of the wild relatives of modern cultivated varieties Figure 20. 1

Causes of Declining Biodiversity • Ecologists have identified four main factors responsible for the loss of biodiversity: – Habitat destruction and fragmentation – Invasive species – Overexploitation – Pollution © 2010 Pearson Education, Inc.

Habitat destruction Figure 20. 4

Overexploitation • People have overexploited wildlife by harvesting at rates that exceed the ability of populations to rebound. • Excessive harvesting has greatly affected – Tigers – Whales – The American bison – Galápagos tortoises © 2010 Pearson Education, Inc.

Bluefin tuna ready for sale Figure 20. 5

COMMUNITY ECOLOGY • An organism’s biotic environment includes – Other individuals in its own population – Populations of other species living in the same area • Species living close enough together for potential interaction is called a community. Video: Clownfish and Anemone © 2010 Pearson Education, Inc.

Figure 20. 6

Competitive exclusion. Two species of Paramecium, P. caudatum and P. aurelia, both feed on bacteria. When grown in separate test tubes, each does well (A), (B). When grown together (C) one species drives the other to extinction. Figure It Out: Which species of Paramecium was the superior competitor? Answer: P. aurelia. © 2010 Pearson Education, Inc. Fig. 17 -5, p. 344

Competition among species 2. Mutualism- interaction between two species that is benefical to both • One example is coral and the unicellular algae that live inside their cells. – The coral gains energy from the sugars produced by the algae. – The algae gain – A secure shelter – Access to light, carbon dioxide and ammonia, a valuable source of nitrogen © 2010 Pearson Education, Inc.

Defense mechanisms for prey • Numerous adaptations for predator avoidance have evolved in prey populations through natural selection. a. Cryptic coloration – Camouflage – A way for prey to hide from predators © 2010 Pearson Education, Inc.

Peppermint Cinnamon Cloves Figure 20. 14

Competition among species 4. Parasitism- predator feeds on the prey with out killing it immediately or ever – Parasites, an animal that lives in or on a host from which it obtains nutrients © 2010 Pearson Education, Inc.

Trophic Structure • Trophic levels- position of level of organization among a food chain or food web • determines the passage of energy and nutrients from plants and other photosynthetic organisms – to herbivores – and then to predators © 2010 Pearson Education, Inc.

• The trophic level that supports all other trophic levels consists of autotrophs, also called producers. • 1 st trophic level- producers- autotrophs that capture sunlight energy and incorporate it into organic compounds © 2010 Pearson Education, Inc.

• All organisms in trophic levels above the producers are consumersheterotrophs that feed on others for food • 2 nd trophic level- primary consumersherbivores- eat plants © 2010 Pearson Education, Inc.

• above the level of primary consumers are carnivores- eat animals • eat the consumers from the level below – 3 rd trophic level- secondary consumers eat primary consumers – 4 th trophic level- tertiary consumers eat secondary consumers – 5 th trophic level- quaternary consumers eat tertiary consumers © 2010 Pearson Education, Inc.

Producers Plant A terrestrial food chain Phytoplankton An aquatic food chain Figure 20. 15 -1

Primary consumers Zooplankton Herbivore Producers Plant A terrestrial food chain Phytoplankton An aquatic food chain Figure 20. 15 -2

Secondary consumers Carnivore Primary consumers Zooplankton Herbivore Producers Plant A terrestrial food chain Phytoplankton An aquatic food chain Figure 20. 15 -3

Tertiary consumers Carnivore Secondary consumers Carnivore Primary consumers Zooplankton Herbivore Producers Plant A terrestrial food chain Phytoplankton An aquatic food chain Figure 20. 15 -4

Quaternary consumers Carnivore Tertiary consumers Carnivore Secondary consumers Carnivore Primary consumers Zooplankton Herbivore Producers Plant A terrestrial food chain Phytoplankton An aquatic food chain Figure 20. 15 -5

• Detritivores- scavengers that consume detritus- the dead material left by all organisms • Decomposers- prokaryotes and fungi that breakdown organic material and convert them into inorganic forms © 2010 Pearson Education, Inc.

Figure 20. 16

Increasing concentrations of PCBs Herring gull eggs 124 ppm Lake trout 4. 83 ppm Smelt 1. 04 ppm Zooplankton 0. 123 ppm Phytoplankton 0. 025 ppm Figure 20. 17

37. 10 Species diversity includes relative abundance and species richness § Species diversity defined by two components – Species richness – Relative abundance § Plant species diversity in a community affects the animals § Species diversity has consequences for pathogens © 2010©Pearson Education, Inc. Copyright 2009 Pearson Education, Inc.

37. 11 Keystone species have a disproportionate impact on diversity § Keystone species – A species whose impact on its community is larger than its biomass or abundance indicates – Occupies a niche that holds the rest of its community in place © 2010©Pearson Education, Inc. Copyright 2009 Pearson Education, Inc.

Ecological Succession • ecological succession- a gradual replacement of one species by other species • may be caused by disturbance 1. Primary succession – Starting state has little or no life – In places such as – lava flows – retreating glacier © 2010 Pearson Education, Inc.

Ecological succession § Pioneer community- 1 st community in succession § Serel stage- successive communities of transition § Climax stage- last community in succession § Bare rock to soil bare rock lichens moss grasses small trees forest © 2010 Pearson Education, Inc.

Example of ecological succession. (A) Mount Saint Helens erupted in 1980. Volcanic ash completely buried the community that previously existed at the base of this volcano. (B) In less than a decade, numerous pioneer species had become established. (C) Twelve years after the eruption, Douglas fir seedlings were taking hold in soils enriched with volcanic ash. © 2010 Pearson Education, Inc. Fig. 17 -10, p. 347

ECOSYSTEM ECOLOGY • ecosystem- community of organisms interacting with one another and their physical environment • An ecosystem includes: – The community of species in a given area – All the abiotic factors, such as – Energy – Soil characteristics – Water © 2010 Pearson Education, Inc.

• A simple terrarium is a microcosm that exhibits the two major processes that sustain all ecosystems: – Energy flow- the passage of energy through the components of the ecosystem – Chemical cycling- the use and reuse of chemical elements such as carbon and nitrogen within the ecosystem Blast Animation: Energy Flow © 2010 Pearson Education, Inc.

Ecological Pyramids • When energy flows as organic matter through the trophic levels of an ecosystem, much of it is lost at each link in the food chain. • Consider the example of a caterpillar. © 2010 Pearson Education, Inc.

Plant material eaten by caterpillar 100 kilocalories (kcal) 35 kcal 50 kcal Feces Cellular respiration 15 kcal Growth Figure 20. 27

• A pyramid of production illustrates the cumulative loss of energy with each transfer in a food chain. • The energy level available to the next higher level – Ranges from 5– 20% – Is illustrated here as 10% © 2010 Pearson Education, Inc.

• The energy available to top-level consumers is small compared to the energy available to lower-level consumers. • This explains why – Top-level consumers require more geographic area – Most food chains are limited to three to five levels © 2010 Pearson Education, Inc.

Human Resource Use • The dynamics of energy flow apply to the human population as much as to other organisms. • When humans eat – Plants, we are primary consumers – Beef or other meat from herbivores, we are secondary consumers – Fish like trout or salmon, we are tertiary consumers © 2010 Pearson Education, Inc.

• The two energy pyramids that follow compare the amount of food available to humans if we are strictly either: – Vegetarians or – Carnivores • Eating meat of any kind is expensive economically and environmentally. © 2010 Pearson Education, Inc.

Concept Check §The caterpillar is a primary consumer in a food chain. How much of the energy captured by the plant and then eaten by the caterpillar is transferred to the next trophic level—the secondary consumer (bird)? • Less than 5% • About 15% • About 50 % • 100% © 2010 Pearson Education, Inc.

Answer §The caterpillar is a primary consumer in a food chain. How much of the energy captured by the plant and then eaten by the caterpillar is transferred to the next trophic level—the secondary consumer (bird)? 2) About 15% © 2010 Pearson Education, Inc.

Chemical Cycling in Ecosystems • Life depends on the recycling of chemicals. – Nutrients are acquired and waste products are released by living organisms. – At death, decomposers return the complex molecules of an organism to the environment. – The pool of inorganic nutrients is used by plants and other producers to build new organic matter. © 2010 Pearson Education, Inc.

The General Scheme of Chemical Cycling • Biogeochemical cycles involve – Biotic components – Abiotic components from an abiotic reservoir where a chemical accumulates or is stockpiled outside of living organisms © 2010 Pearson Education, Inc.

1. The Carbon Cycle • The cycling of carbon between the biotic and abiotic worlds is accomplished mainly by the reciprocal metabolic processes of a. Photosynthesis – takes in CO 2 b. Cellular respiration – releases CO 2 c. Burning of fossil fuels and volcanic eruptions- releases CO 2 Blast Animation: Carbon Cycle © 2010 Pearson Education, Inc.

CO 2 in atmosphere 5 Burning 3 Cellular respiration Photosynthesis 1 Wood and fossil fuels Decomposition Higher-level consumers Primary consumers Wastes; death Decomposers (soil microbes) © 2010 Pearson Education, Inc. Plants, algae, cyanobacteria 4 Detritus 2 Plant litter; death

2. phosphorus cycle § Organisms require phosphorus for nucleic acids, phospholipids, and ATP a. Plants absorb phosphate ions in the soil and build them into organic compounds b. Phosphates are returned to the soil by decomposers © 2010©Pearson Education, Inc. Copyright 2009 Pearson Education, Inc.

6 Uplifting of rock 3 Weathering of rock Runoff Phosphates in rock Animals Plants 1 Assimilation 2 Phosphates in solution Phosphates in soil (inorganic) Detritus 5 Rock Precipitated (solid) phosphates Decomposition Decomposers in soil 4 © 2010 Pearson Education, Inc.

2. The Nitrogen Cycle • Nitrogen is – An ingredient of proteins and nucleic acids – Essential to the structure and functioning of all organisms • Nitrogen has two abiotic reservoirs: – The atmosphere – The soil © 2010 Pearson Education, Inc.

• nitrogen fixation converts gaseous N 2 to ammonia and nitrates, which can be used by plants. • Most of the nitrogen available in natural ecosystems comes from biological fixation performed by two types of nitrogen-fixing bacteria. • decomposition- bacteria and fungi return N to the soil Blast Animation: Nitrogen Cycle © 2010 Pearson Education, Inc.

Nitrogen (N 2) in atmosphere 8 Animal Plant 6 Assimilation by plants Organic compounds Nitrogen fixation Death; wastes 5 Denitrifiers Organic compounds 3 Nitrates in soil (NO 3–) Nitrogen-fixing bacteria in root nodules Detritus Free-living nitrogen-fixing bacteria and cyanobacteria Decomposers 4 1 Nitrifying bacteria 7 Decomposition Ammonium in soil © 2010 Pearson Education, Inc. (NH 4+) Nitrogen fixation 2

Nutrient Pollution • The growth of algae and cyanobacteria in aquatic ecosystems is limited by low nutrient levels, especially of phosphorus and nitrogen. • Nutrient pollution occurs when human activities add excess amounts of these chemicals to aquatic ecosystems. © 2010 Pearson Education, Inc.

Algal growth as a result of phosphate pollution Figure 20. 35

• Nitrogen runoff from Midwestern farm fields has been linked to an annual summer dead zone in the Gulf of Mexico. • Bacteria feed on algae blooms in these areas and deplete the supply of oxygen. © 2010 Pearson Education, Inc.

Mississippi River Gu f. M lf o exico Light blue lines represent rivers draining into the Mississippi River (shown in dark blue) f M e x i co o f ul G Summer u G Winter c f Mexi o o lf Figure 20. 36

Concept Check §Matter that makes up life is recycled and reused. Which of the following is not recycled primarily through the atmosphere (rapid) but instead is cycled through the rock cycle (slow by rock formation and weathering). • nitrogen • carbon • water • phosphorus © 2010 Pearson Education, Inc.

Answer §Matter that makes up life is recycled and reused. Which of the following is not recycled primarily through the atmosphere (rapid) but instead is cycled through the rock cycle (slow by rock formation and weathering). 4) phosphorus © 2010 Pearson Education, Inc.

Thinking Like a Scientist §This figure plots the loss of nitrate from a deforested watershed on the Hubbard Brook study site. After the tree cutting was complete about how much more nitrate left the watershed during runoff? • The runoff had 3 times the normal nitrate. • The runoff had 15 times the normal nitrate. • The runoff had 60 times the normal nitrate. © 2010 Pearson Education, Inc.

Answer §This figure plots the loss of nitrate from a deforested watershed on the Hubbard Brook study site. After the tree cutting was complete about how much more nitrate left the watershed during runoff? 3) The runoff had 60 times the normal nitrate. © 2010 Pearson Education, Inc.

Thinking Like a Scientist §Snow is a source of nitrate. Based on this plot during what season do nitrate levels usually peak in the runoff? (Assume that the vertical white grid lines mark the beginning of the year. ) • Winter. • Spring. • Fall. © 2010 Pearson Education, Inc.

Answer §Snow is a source of nitrate. Based on this plot during what season do nitrate levels usually peak in the runoff? (Assume that the vertical white grid lines mark the beginning of the year. ) 2) Spring. © 2010 Pearson Education, Inc.

Science and Society §During the summer of 2003 the entire western U. S. seemed to experience large forest fires. One of the fires was in fact the result of a controlled “burn” getting out of control. The controlled burn is a management technique that seeks to remove the accumulated litter in forest so that fires will not burn out of control. Fire is a part of the western forest’s ecosystem. The U. S. Forest service has implemented a number of forest clean up plans—including increasing timber harvest. However, people continue to build homes in ecosystems where fire is to be expected. Should development be limited in fire prone areas? Strongly Disagree © 2010 Pearson Education, Inc. A B C D E Strongly Agree

Science and Society §Travelers into and out of our country are asked about agricultural products. “Are you bringing into the country fruits or vegetables purchased abroad? ” Of course, the primary reason is to prevent exotic pest species from entering our ecosystems. As a traveling citizen do you take precautions to minimize the possibility that you could accidentally bring foreign organisms into the U. S. ? Strongly Disagree © 2010 Pearson Education, Inc. A B C D E Strongly Agree

Science and Society §The tall grass prairies of eastern Kansas are the largest remaining tract of the tall-grass prairie ecosystem. Each spring to recycle nutrients and to control brush, ranchers burn large areas of the tall-grass prairie. This has been done for more than a hundred years and the Native Americans also burned the prairie to attract bison. Recently, the EPA issued a document that suggested that range burning could be contributing to high ozone levels in nearby urban areas and suggested that the ranchers curtail their burning. Do you agree that urban ozone levels should take precedent over range management of an endangered ecosystem? Strongly Disagree © 2010 Pearson Education, Inc. A B C D E Strongly Agree