AP Review Chapters 7, 8, & 13

By: Adrienne Damicis

Chapter 7: Aquatic Biodiversity

This chapter addresses the following questions:

o What are the basic types of aquatic life zones, and what factors influence the kinds of life they contain?

o What are the major types of saltwater life zones, and how do human activities affect them?

o What are the major types of freshwater life zones, and how do human activities affect them?

o How can we help sustain aquatic life zones?

Case Study: Why should we care about coral reefs?

• formed by massive colonies of tiny animals called polyps

• they build reefs by secreting a protective crust of limestone around their bodies which remains after the polyps die

• there is a mutually beneficial relationship between the polyps and tiny algae called zooxanthellae

Case Study (Cont.)

• Coral bleaching occurs when a coral becomes stressed and expels most of its algae, leaving behind a white skeleton of calcium carbonate.o Causes include increased water temperature and

runoff of silt that covers the coral and prevents photosynthesis.

o More than 1/4 of the world's coral reefs have been lost to coastal development, pollution, overfishing, warmer ocean temperatures, and other stresses.

Case Study (Cont.)

Ecological and economic services:

o removal of carbon dioxide from the atmosphereo natural barriers that protect the coastline from

erosion by waves and stormso support at least 1/4 of marine specieso support fishing and tourism industries worth billions

of dollars each year

Aquatic Life Zones

• Saltwater or marine (estuaries, coastlines, coral reefs, coastal marshes, mangrove swamps and oceans)

• Freshwater

Organisms in Aquatic Life Zones

• Planktono Phytoplankton- plant plankton that are producerso Zooplankton- animal plankton that are primary or

secondary consumerso Ultraplankton- photosynthetic bacteria no more than

2 micrometers wide.

Organisms in Aquatic Life Zones

• Nekton- strongly swimming consumers (fish, turtles, whales, etc.)

• Benthos- dwells on the bottom (barnacles, oysters, crabs, worms, etc.)

• Decomposers- break down the organic compounds and the dead bodies and wastes of aquatic organisms into simple nutrient compounds for use by producers (mostly bacteria)

Benefits of a Marine Ecosystem

• Ecological: climate moderation, CO2 absorption, nutrient cycling, waste treatment and dilution, habitats and nursery areas for marine and terrestrial species.

• Economic: food, pharmaceuticals, harbors and transportation routes, recreation, employment, minerals, offshore oil and natural gas, building materials.

Estuaries and Coastal Wetlands

• Estuary- partially enclosed area of coastal water where seawater mixes with freshwater and nutrients from rivers, streams, and runoff from land.

• Coastal Wetlands- land covered with water all or part of the year (river mouths, inlets, bays, sounds, mangrove forest swamps, and salt marshes.

Ocean Shores

• Intertidal zone- area of shoreline between low and high tideo difficult to live in b/c of changing conditionso many organisms survive by digging into the sand,

hold on to something, or hide in protective shells

• Rocky shores- creates pools o contains a great variety of species with different

niches

• Barrier beaches- sandy shores o home to many shorebirdso organisms survive by staying hidden from view,

burrowing, digging, and tunneling in the sand.

Barrier Islands

• Low, narrow, sandy islands that form offshore from a coastline. o Help protect the mainland, estuaries, and coastal

wetlands from approaching storm waveso Heavily targeted for real estate developmento Dangerous place to live b/c the beaches are

constantly shifting and eroding and floods are common.

Biological Zones in the Open Sea

• Euphotic Zone- lighted upper zone where phytoplankton carry out photosynthesiso nutrient levels are low (except around upwellings)

and DO levels are high.o Large predatory fish populate this zone (tuna,

swordfish, etc.)

• Bathyal Zone- dimly lit middle zone, doesn't contain phytoplankton. o Zooplankton and smaller fish populate this zone

Biological Zones in the Open Sea

• Abyssal Zone- lowest zone, dark, and cold.o Little DOo Enough nutrients on the ocean floor to support 98%

of the species living in the ocean.

• Most organisms of the deep waters get their food from detritus drifting down.o Deposit Feeders- take mud into their guts and

extract nutrients from it.o Filter Feeders- pass water through or over their

bodies and extract nutrients from it.

Open Sea

• Average primary productivity and NPP per unit area are low in the open sea except at an occasional equatorial upwelling.

• Largest contributor to the earth's overall NPP

Freshwater Life Zones

• Lentic bodies- standing bodies of freshwater (lakes, ponds, inland wetlands, etc.)

• Lotic systems- flowing systems such as streams and rivers.

Freshwater Lakes• Littoral Zone- top layer; shallow sunlit water

o high biological diversity and adequate nutrients

• Limnetic Zone- open, sunlit water surface layer away from the shoreo main photosynthetic body of the lake, supplies most

of the food and oxygen for the lake's consumers

• Profundal Zone- deep, open water where it's too dark for photosynthesiso Low DO

• Benthic Zone- bottom of the lakeo mostly decomposers and detritus feeders o nourished by detritus that falls from zones above

Freshwater Lakes

• Oligotrophic- small supply of plant nutrientso often deep, with steep bankso crystal clear water, small populations of

phytoplankton and fish, low NPP

• Eutrophic- large or excessive supply of nutrients o typically shallow, murky water, high NPP

• Mesotrophic- between the two extremes of nutrient enrichment

Freshwater Streams and Rivers

• Source Zone- headwaters, or mountain highland streams of cold, clear water, rush over waterfalls and rapidso dissolves large amounts of oxygen from the airo lack of nutrients, low productivity

• Transition Zone- headwater streams merge to form wider, deeper streams that flow down gentler slopeso warmer water, more producers

Freshwater Streams and Rivers

• Floodplain Zone- streams join into wider and deeper rivers that meander across broad, flat valleyso higher temperatures, less DO, high concentrations

of silto support fairly large populations of producers and

rooted aquatic plants along the shoreso Often polluted from excessive inputs of nutrients and

other anthropogenic pollutants

Human Activities on Freshwater Systems

• We have built dams, levees, and dikes that reduce the flow of water and alter wildlife habitats in rivers; established nearby cities and farmlands that pollute streams and rivers; and filled in inland wetlands to grow food and build cities.

Chapter 13: Sustaining Aquatic Biodiversity

This chapter addresses the following questions:

o What is aquatic biodiversity, and what is its

economic and ecological importance?o How are human activities affecting aquatic

biodiversity?o How can we protect and sustain marine biodiversity?o How can we manage and sustain the world's marine

fisheries?o How can we protect, sustain, and restore wetlands?o How can we protect, sustain, and restore lakes,

rivers, and freshwater fisheries?

Aquatic Biodiversity

• oceans cover 71% of the planet's surface

• 63% of known fish species exist in marine systems - 50% in coastal waters - 12% in the deep sea - 1% in the open ocean - 37% live in freshwater systems

Marine Biodiversity• Greatest marine biodiversity occurs in coral

reefs, estuaries, and the deep-ocean floor

• Biodiversity is higher near coasts than in the open sea because of the great diversity of producers, habitats, and nursery areas

• Biodiversity is higher in the bottom region of the ocean because of the greater variety of habitats and food sources on the ocean bottom

• The lowest marine biodiversity probably is found in the middle depths of the open ocean

Maintaining Aquatic Sustainability

• Integrated Coastal Management- community-based effort to develop and use coastal resources more sustainably. The overall aim is for groups competing for the use of coastal resources to identify shared problems and goals. Then they attempt to develop workable, cost-effective, and adaptable solutions that preserve biodiversity and environmental quality while meeting economic and social needs.

Solutions to Protecting Wetlands

• legally protect existing wetlands

• steer development away from existing wetlands

• use mitigation banking only as a last resort

• require creation and evaluation of a new wetland before destroying an existing wetland

• restore degraded wetlands

• try to prevent and control invasions by nonnative species

Chapter 8: Community Ecology

The chapter addresses the following questions:

o What determines the number of species in a community?

o What different roles do species play in a community?o How do species interact with one another in a

community?o How do communities change as environmental

conditions change?o Does high biodiversity increase the stability of a

community?

Island Ecology

• Theory is island biogeography- a balance between two factors determines the number of different species found on an island: the rate at which new species immigrate to the island and the rate at which existing species become extinct on the island.o Features that affect these rates are the island's size

and its distance from the nearest mainland.

Types of Species• Native species- normally live and thrive in a particular community

• Nonnative species- also called invasive or alien species

• Indicator Species- serve as early warnings of damage or danger to a community

• Keystone Species- have a much larger effect on the types and abundances of many other species in a community than their numbers would suggest

• Foundation Species- create and enhance habitat that benefits other species

Species Interactions

• Interspecific competition- competition for shared or scarce resources such as space and foodo Resource partitioning- species competing for similar

scarce resources evolve more specialized traits that allow them to use shared resources at different times, in different ways, or in different places

• Predation- members of one species feed directly on all or part of a living organism of another species.

Species Interactions

• Parasitism- one species feeds on part of another organism (the host) usually by living on or in the hosto the parasite benefits and the host is harmed

• Mutualism- two species interact in a way that benefits botho pollination mutualism between plants and animals is

the most common form of mutualism

• Commensalism- interaction that benefits one species but has little, if any, effect on the other species

Ecological Succession

• Ecological succession- the gradual change in species composition of a given area

• Primary succession- the gradual establishment of biotic communities on nearly lifeless ground

• Secondary succession- biotic communities are established in an area where some type of biotic community is already present

Primary Succession Species

• Pioneer species- attach themselves to inhospitable patches of bare rocko vital to soil formation

• Early successional plant species- grow close to the ground, can establish large populations quickly under harsh conditions, and have short lives.

• Midsuccessional plant species- herbs, grasses, and low shrubs.

• Late successional plant species- mostly trees that can tolerate shade

Ecological Stability, Complexity, and Sustainability

• Living systems maintain some degree of stability or sustainability through constant change in response to changing environmental conditions

• Inertia or Persistence- the ability of a living system to resist being disturbed or altered

• Constancy- the ability of a living system to keep its numbers within the limits imposed by available resources

• Resilience- the ability of a living system to repair damage after an external disturbance that is not too drastic