Chapter 1: The Living World: Ecosystems (copy) Revised

Species

Organisms that resemble each other; are similar in genetic makeup, chemistry, and behavior; and are able to interbreed and produce fertile offspring.

Interspecific

Means between different species.

Community

Population of different species.

Ecological Niche

A particular area within a habitat occupied by an organism, as well as the function of that organism within its ecological community.

Niche

It reflects the specific adaptations that a species has acquired through evolution.

Generalists

Able to survive on a wide variety of food resources, Able to withstand a wide range of environmental conditions

Specialists

Specific/limited number of prey, Prone to extinction, sensitive to environmental change, Live in narrow niches

Symbiosis

A term used to describe any type of close and long-term biological interaction between two different biological organisms of the same or different species.

Amensalism

The interaction between two species whereby one species suffers and the other species is not affected.

Commensalism

The interaction between two species whereby one organism benefits and the other species is not affected.

Competition

It can be either intraspecific and interspecific. It is the driving force of evolution whether it is for food, mating partners, or territory.

Intraspecific

Competition between members of the same species.

Interspecific

Competition between members of different species.

Mutualism

The interaction between two species whereby both species benefit.

Parasitism

The interaction between two species whereby one species is benefited, and the other species is harmed.

Opportunistic predators

An opportunistic predator is an animal that preys on whatever prey is available to it at the time, rather than specializing in one particular type of prey. They take advantage of any opportunity to hunt and feed, regardless of the species or size of the prey.

Specialist predators

These predators only prey upon certain organisms.

Saprottrophism

Saprotrophs obtain their nutrients from dead or decaying plants or animals through the absorption of soluble organic compounds.

Law of Tolerance

It states that the existence, abundance, and distribution of species depend on the tolerance level of each species to both physical and chemical factors.

Morphological partitioning

It occurs when two species share the same resource but have evolved slightly different structures to utilize the same resource

Spatial partitioning

It occurs when competing species use the same resource by occupying different areas or habitats within the range of occurrence of the resource

Temporal partitioning

It occurs when two species eliminate direct competition by utilizing the same resource at different times

Deserts

Defined in terms of the amount of rainfall they receive, not temperature. They cover about 20% of Earth’s surface and occur where rainfall is less than 20 inches (50 cm) per year.

Arctic tundra

It is a cold desert due to the low amount of rainfall it receives yearly.

Succulents

Plants that have fleshy leaves or stems that store water.

Aestivation

A summer hibernation.

Forests

It cover about one-third of Earth's land surface, mostly in North America, the Russian Federation, and South America, and account for 75% of gross primary productivity and plant biomass.

Closed canopy

Tree crowns cover more than 20% of the ground’s surface.

Open canopy

Tree crowns cover less than 20% of the ground surface.

Temperate Deciduous Forests

• Occur in eastern North America, northeastern Asia, and western and central Europe.

• Have a distinct winter, moderate climate, and a 140–200-day growing season during four to six frost-free months.

Temperate Deciduous Forests

• Temperature varies from –20°F to 85°F (–30°C to 30°C).

• Precipitation averages 30–60 inches (75–150 cm) per year.

• Fertile soil is enriched by decaying leaf litter.

Temperate Deciduous Forests

The tree canopy allows light to penetrate, resulting in well-developed and diverse understory vegetation and animal stratification.

Temperate Coniferous Forest

• Found in temperate regions with warm summers, cool winters, and enough rainfall to support forests.

• Common in coastal areas with mild winters and heavy rainfall, or inland in drier climates or mountains.

Temperate Coniferous Forest

• These forests have cedar, cypress, fir, juniper, pine, redwood, and spruce.

• These forests have two layers:

  • Overstory

  • Understory

• Some forests have a shrub layer.

Temperate Coniferous Forest

• In winter, when food is scarce, many animals hibernate to conserve energy and build fat in summer.

• Birds have feathers and many animals have thick fur to protect them from cold weather.

• Some animals migrate to warmer climates during the winter months.

Taiga

Largest terrestrial biome; found in northern Eurasia, North America, Scandinavia, and two-thirds of Siberia.

Southern Taiga

Also known as *boreal forest*, consists primarily of cold-tolerant evergreen conifers with needle-like leaves, such as pines, spruces, and larches.

Northern Taiga

It is more barren as it approaches the tree line and the tundra biome.

Grasslands

These are characterized as lands dominated by grasses rather than by large shrubs or trees.

Savannas

These are grasslands with scattered individual trees and cover almost half the surface of Africa and large areas of Australia, South America, and India.

Temperate Grasslands

Here grasses are the dominant vegetation, while trees and large shrubs are absent.

Tundra

It has extremely low temperatures, large repetitive population changes, limited soil nutrients, little precipitation, low biotic diversity, poor drainage, short growing and reproductive seasons, and simple vegetation structure.

Arctic tundra

Due to the ________’s unique conditions, the biota is highly specialized and sensitive to environmental change.

Arctic tundra

It circles the North Pole and extends south to the taiga, is cold, dry, and desert-like.

Permafrost

A layer of permanently frozen subsoil.

Alpine tundra

It is located on mountains throughout the world at high altitudes where trees cannot grow.

Aquatic Biomes

Antarctic, marine, lakes, wetlands, and rivers

Antarctica

It has the coldest climate on Earth.

ice sheet

It is formed from compressed snow that rarely melts.

Krill

These are key food sources in this ecosystem and serve as food for many predators.

Convection

The circular motion that occurs when warmer air or liquid rises, while the cooler air or liquid sinks.

conveyor belt

Thermohaline currents drive a "_____" of ocean water that moves constantly, unlike most surface currents, which are driven by winds.

Littoral Zone

Also known as the *intertidal zone*, it is the part of the ocean that is closest to the shore.

Neretic Zone

Also known as the *sublittoral zone*, this zone extends to the edge of the continental shelf.

Photic Zone

The uppermost layer of water in a lake or ocean that is exposed to sunlight down to the depth where 1% of surface sunlight is available. The layer just above the depth where the rate of carbon dioxide uptake by plants is equal to the rate of carbon dioxide production by animals.

zooxanthellae

Most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates, commonly known as _______, that live within their tissues.

Fringing reefs

• They grow near the coastline around islands and continents and are separated from the shore by narrow, shallow lagoons.

• They are the most common type of reef.

Barrier reefs

• These are also parallel to the coastline but are separated by deeper, wider lagoons.

• At their shallowest point, they can reach the water’s surface, forming a “barrier” to navigation.

Atolls

• These are rings of coral that create protected lagoons and are usually located in the middle of the sea.

• They usually form when islands, often the tops of underwater volcanoes, surrounded by fringing reefs, sink into the sea, or the sea level rises around them.

Benthic Zone

The bottom of lake, organisms can tolerate cool temperatures and low oxygen levels.

Limnetic Zone

A well-lit, open surface water, farther from shore, extends to a depth penetrated by light, occupied by phytoplankton, zooplankton, and higher animals; produces food and oxygen that supports most of a lake’s consumers

Littoral Zone

It is shallow, close to shore, extends to depth penetrated by light; rooted and floating plants flourish

Profundal Zone

It is deep, no-light regions, too dark for photosynthesis; low oxygen levels; inhabited by fish adapted to cool, dark waters

Oligotrophic (Young Lake)

Deep, cold, small surface area relative to depth; nutrient-poor, phytoplankton are sparse; not very productive; doesn’t contain much life; waters often very clear; and sediments are low in decomposable organic matter.

Mesotrophic (Middle-Aged Lake)

Moderate nutrient content and moderate amounts of phytoplankton; reasonably productive.

Eutrophic (Old Lake)

Shallow, warm, large surface area relative to depth; Waters often murky;

stratification

The ______ or layering of water in lakes is the result of density changes caused by shifts in temperature.

Wetlands

These are areas that are covered with water at some point in the year and that support aquatic plants.

Source Zone

• Contains headwaters or headwater streams and often begins as springs or snowmelt of cold, clear water with little sediment and relatively few nutrients.

• Narrow rocky channels, creating swift currents.

Transition Zone

• Contains slower, warmer, wider, and lower-elevation moving streams, which eventually join to form tributaries.

• The water is less clear as it contains more sediment and nutrients, with the substrate beginning to accumulate silt.

Floodplain Zone

• As a result of large amounts of sediment and nutrients, the water is murky and warmer.

• Tributaries join to form rivers, which empty into oceans at estuaries.

Riparian areas

These are lands adjacent to creeks, lakes, rivers, and streams that support vegetation dependent upon free water in the soil.

Carbon

It is exchanged among the biosphere, geosphere, hydrosphere, and atmosphere and is the basic building block of life and the fundamental element found in carbohydrates, fats, proteins, and nucleic acids.

ocean acidification

The creation of coral reefs and the viability of externally fertilized egg cells are disrupted by __________ caused by carbon dioxide absorption.

Terrestrial Biosphere

Forests store about 90% of the planet’s above-ground carbon and about 75% of the planet’s soil carbon.

Oceans

The carbon in carbon dioxide dissolved in seawater is utilized by phytoplankton and kelp for photosynthesis.

Sedimentary Deposits

Limestone (CaCO3) is the largest reservoir of carbon in the carbon cycle.

Nitrogen

It makes up 78% of the atmosphere.

Though __________ is abundant, it has limited use biologically, which leads to a scarcity of usable forms of nitrogen in terrestrial and aquatic ecosystems.

atmospheric nitrogen (N2)

Fossil fuel combustion, inorganic fertilizer use, and wastewater and sewage production have drastically altered the _________.

nitrogen cycle

Nitrogen

• It increases water acidification, eutrophication, and toxicity.

• It is needed for photosynthesis and plant growth in chlorophyll.

• It availability affects primary production and decomposition.

Nitrogen Fixation

Atmospheric nitrogen is converted into ammonia (NH3) or nitrate ions (NO3–), which are biologically usable forms of nitrogen.

The __________, in which atmospheric nitrogen is converted to nitrogen oxides by lightning and deposited in the soil by rain, where it is assimilated by plants and either eaten by animals or decomposed back to elemental nitrogen by bacteria, includes the following processes:

natural cycling of nitrogen

The key participants in nitrogen fixation are legumes, such as alfalfa, clover, and soybeans, and nitrogen-fixing bacteria known as ________.

Rhizobium

Nitrification

Ammonia (NH3) is converted to nitrite (NO2–) and nitrate (NO3–), which are the most useful forms of nitrogen to plants.

Ammonification

Decomposing bacteria convert dead organisms and wastes, which include nitrates, uric acid, proteins, and nucleic acids, to ammonia (NH3) and ammonium ions (NH4+)—biologically useful forms.

Denitrification

Anaerobic bacteria convert ammonia into nitrites (NO2–), nitrates (NO3–), nitrogen gas (N2), and nitrous oxide (N2O) to continue the cycle.

nitrogen oxides (NOx)

Fossil fuel combustion has sevenfold increased atmospheric _________, particularly nitrogen dioxide.

____ produces tropospheric ozone, smog, acid rain, and nitrogen inputs to ecosystems.

NOx

_______ in the atmosphere has tripled as a result of human activities since the Industrial Revolution.

Ammonia (NH3)

Nitrous oxide (N2O)

This greenhouse gas breaks down and destroys atmospheric ozone in the stratosphere.

Nitrification

Reduced nitrogen compounds are sequentially oxidized to nitrite and nitrate.

Denitrification

Reducing nitrate and nitrite to gaseous forms of nitrogen.

Phosphorus

It is essential for the production of nucleotides, ATP, fats in cell membranes, bones, teeth, and shells.

Water cycle

It is powered by energy from the sun, which evaporates water from oceans, lakes, rivers, streams, soil, and vegetation.

The water cycle is in a state of __________ by which the rate of evaporation equals the rate of precipitation.

dynamic equilibrium

Capillary action

A result of hydrogen bonding, helps tree roots take up water, allowing trees to grow as large as they do.

Floating ice

Essential to life near the poles, results from the different ways water molecules arrange themselves at different temperatures.

Recharge zone

The surface area above an aquifer that supplies water to the aquifer

Unsaturated zone

The zone immediately below the land surface where the open spaces in the soil contain both water and air, but are not totally saturated with water