Ch. 12

Interaction of Life

Living Earth

• Biosphere – The part of the earth that supports life– Includes the top portion of earths crust, all the

waters that cover earths surface, and the atmosphere that surrounds earth

– The biosphere is made up of different environments that are homes to different organisms

– These different environments are called Biomes

Biome #1 Aquatic

• The aquatic biome can be broken down into two basic regions, freshwater (i.e, ponds and rivers) and marine (i.e, oceans and

estuaries). • Freshwater is defined as having a low salt concentration—usually

less than 1%.• There are different types of freshwater regions: ponds and lakes,

streams and rivers, and wetlands.

Wetlands

• Wetlands are areas of standing water that support aquatic plants.

• Marshes, swamps, and bogs are all considered wetlands.

• Plant species adapted to the very moist and humid conditions are called hydrophytes. – These include pond lilies, cattails, sedges, tamarack,

and black spruce. • Wetlands have the highest species diversity of all

ecosystems. Many species of amphibians, reptiles, birds (such as ducks and waders), and furbearers can be found in the wetlands.

• not always covered by Water

• Water Table is near or above the surface of Wetland

• Two Types: coastal (also known as tidal or estuarine wetlands) and inland (also known as non-tidal, freshwater (Everglades)

Biome #2 Deserts

• Deserts cover about one fifth of the Earth’s surface

• rainfall is less than 50 cm/year. Warm Weather Desert - Sahara of North Africa and the deserts of the southwestern U.S., Mexico, and Australia, occur at low latitudes,

• cold deserts, occur in the basin and range area of Utah and Nevada and in parts of western Asia.

• Most deserts have a considerable amount of specialized vegetation, as well as specialized vertebrate and invertebrate animals

                                                

        

Biome #3 Forest

• Today, forests occupy approximately one-third of Earth’s land area,

• account for over two-thirds of the leaf area of land plants,

• and contain about 70% of carbon present in living things

• There are three major types of forests, classed according to latitude: – tropical – temperate – boreal forests (taiga)

• Tropical – Tropical forests are characterized by the greatest

diversity of species.– They occur near the equator. – winter is absent, and only two seasons are present

(rainy and dry). The length of daylight is 12 hours and varies little.

– Temperature is on average 20-25° C and varies little throughout the year:

– Precipitation is evenly distributed throughout the year, with annual rainfall exceeding 2000 mm.

– Soil is nutrient-poor and acidic. Decomposition is rapid and soils are subject to heavy leaching.

– Canopy in tropical forests is multilayered and continuous, allowing little light penetration.

– Flora is highly diverse: one square kilometer may contain as many as 100 different tree species. Trees are 25-35 m tall, and shallow roots, mostly evergreen, with large dark green leaves. Plants such as orchids, bromeliads, vines (lianas), ferns, mosses, and palms are present in tropical forests.

– Fauna include numerous birds, bats, small mammals, and insects.

                      

Jaguar Orangutans

Tree Frog Caiman

• Temperate forests– occur in eastern North America, northeastern Asia,

and western and central Europe. – Well-defined seasons with a distinct winter

characterize this forest biome. – Moderate climate and a growing season of 140-200

days during 4-6 frost-free months distinguish temperate forests.

– Temperature varies from -30° C to 30° C.– Precipitation (75-150 cm) is distributed evenly

throughout the year.

– Soil is fertile, enriched with decaying litter.– Canopy is moderately dense and allows light to

penetrate, resulting in well-developed and richly diversified understory vegetation and stratification of animals.

– Flora is characterized by 3-4 tree species per square kilometer. Trees are distinguished by broad leaves that are lost annually and include such species as oak, hickory, beech, hemlock, maple, basswood, cottonwood, elm, willow, and spring-flowering herbs.

– Fauna is represented by squirrels, rabbits, skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.

• Boreal forests, or taiga,– represent the largest terrestial biome. Occuring

between 50 and 60 degrees north latitudes, boreal forests can be found in the broad belt of Eurasia and North America

– Seasons are divided into short, moist, and moderately warm summers and long, cold, and dry winters.

– The length of the growing season in boreal forests is 130 days.

– Temperatures are very low.– Precipitation is primarily in the form of snow, 40-100

cm annually.

– Soil is thin, nutrient-poor, and acidic.– Canopy permits low light penetration, and as

a result, understory is limited.– Flora consist mostly of cold-tolerant

evergreen conifers with needle-like leaves, such as pine, fir, and spruce.

– Fauna include woodpeckers, hawks, moose, bear, weasel, lynx, fox, wolf, deer, hares, chipmunks, shrews, and bats.

•

Biome #4 Grasslands

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

• There are two main divisions of grasslands: (1) tropical grasslands, called savannas, and (2) temperate grasslands

• Savannas

– Savanna is grassland with scattered individual trees.

– Savannas of one sort or another cover almost half the surface of Africa (about five million square miles, generally central Africa) and large areas of Australia, South America, and India.

– . Savannas are always found in warm or hot climates where the annual rainfall is from about 50.8 to 127 cm (20-50 inches) per year.

– It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur.

– Savannas receive an average annual rainfall of 76.2-101.6 cm (30-40 inches). However, certain savannas can receive as little as 15.24 cm (6 inches) or as much as 25.4 cm (10 inches) of rain a year.

• Temperate Grasslands – Temperate grasslands are characterized

as having grasses as the dominant vegetation.

– Trees and large shrubs are absent.– Temperatures vary more from summer to

winter, and the amount of rainfall is less in temperate grasslands than in savannas.

– Precipitation in the temperate grasslands usually occurs in the late spring and early summer.

– The annual average is about 50.8 to 88.9 cm (20-35 inches). The temperature range is very large over the course of the year. Summer temperatures can be well over 38° C (100 degrees Fahrenheit), while winter temperatures can be as low as -40° C (-40 degrees Fahrenheit).

Biome #5 Tundra

• is the coldest of all the biomes.• It is noted for its frost-molded landscapes,

extremely low temperatures, little precipitation, poor nutrients, and short growing seasons.

• Dead organic material functions as a nutrient pool.

• The two major nutrients are nitrogen and phosphorus. – Nitrogen is created by biological fixation, – and phosphorus is created by precipitation.

• Tundra is separated into two types: arctic tundra and alpine tundra.

• The growing season ranges from 50 to 60 days.• The average winter temperature is -34° C (-30° F), but

the average summer temperature is 3-12° C (37-54° F) which enables this biome to sustain life.

• Rainfall may vary in different regions of the arctic.• Yearly precipitation, including melting snow, is 15 to 25

cm (6 to 10 inches). • Soil is formed slowly. • A layer of permanently frozen subsoil called permafrost

exists, consisting mostly of gravel and finer material.

Snow Owl

Musk Oxen

Arctic Fox

Polar Bear

Ecosystems

• The amount of energy received by the sun makes the temperature just right for life to exist

• An ecosystem consists of all the organisms living in an area and the nonliving features of their environment – Nonliving features: Water, temperature, sunlight, soil,

and air

• Ecology is the study of the interaction that occurs between living and nonliving features

• Population – Population is made up of all the organisms in

an ecosystem that belongs to the same species

– Ecologist often study how populations interact • This is called the community • Community refers to all the different populations in

an ecosystem

• Habitats – The place in which an organism lives is called

its habitat• Trees would be a birds habitat• Forest floor would be a salamanders habitat

– An animals habitat provides the kinds of food and shelter, the temperature, and the amount of moisture the organism needs to survive

Population

• Competition occurs when two or more organism seek the same resource

• Organism compete for – Food– Water– Living space – Mates

• Competition Limits population size

• Competition for food, living space, or other resources can prevent population growth

• Most intense competition in nature is usually between organisms of the same species

• Competition also takes place among individual of different species

contest among organisms for the limited resources of an ecosystem

                             

• Population size—indicates whether a population is healthy and growing– 1. Population density—the size of a

population that occupies a specific area– 2. Two ways to measure the size of a wildlife

population• a. Trap-mark-release method• b. Sample count method

• 3. Elements that affect population size– a. Limiting factor—any living or nonliving feature that

restricts the number of individuals in a population– b. Carrying capacity—the largest number of

individuals of one species that an ecosystem can support

– c. Biotic potential—the maximum number of offspring that parent organisms can produce

– d. Birth and death rates– e. Movement of organisms into or out of an area

• Exponential growth—the larger a population becomes, the faster it grows – After population grows so large it slows and

the number of organism remains fairly constant (reaches equilibrium)

– The ecosystem has reached its carrying capacity

 

                            

                                                                                

      

Simply stated: Every living organism has to eat.  When organisms eat - they reproduce.  Assuming generation overlap, the population will grow.  As food availability increases, a population will increase -- tracking its food availability.

                             

                                                                                

   

• Earths human population shows exponential growth

• In the year 2000, earths human population exceeded 6 billion people

• By the year 2050 earths population could reach 10 billion

• Discussion Question

• If a population were decreasing, what kinds of questions would an ecologist ask to determine the problem?

• Are there any limiting factors?• Are there enough food, water, living space, and

mates available? • Has the population reached its carrying

capacity? • Does the population have a low biotic poten-tial?• Is something causing the death rate to increase,

or the birth rate to decrease? • Are organisms moving out of the area?

Interactions within Communities

Obtaining energy

• The energy that fuels life on earth is derived from the sun

• Producers (plants) carry out photosynthesis to produce energy rich molecules (glucose – Sugar)– Glucose molecules serve as food– Made up Carbon, oxygen, and hydrogen– When this molecules break apart (in digestion) they

release energy to fuel life processes

• Producers– Most producers contain a green pigment

called Chlorophyll (Absorbs Sunlight)– Some producers makes energy-rich

molecules through a process called Chemosynthesis.

• Found near volcanic vents• Use inorganic substances from the water

• Consumers – Cannot make their own food– Make energy by eating other organisms – Four categories of consumers

• Herbivores – eat nothing but plants– Rabbits, deer, cows, horses

• Omnivores – Eat both plants and animals– Pigs, humans, bears

• Carnivores –eat other animals– Spiders, frogs, lions, tigers

• Decomposers – consume waste and dead organisms, helps recycle once living material

– Fungi, earthworms, and bacteria

Herbivores

Carnivores

Food Chains

• Shows how organism depend on each other

• Show the feeding relationship in an ecosystem – Plants are producers– Herbivore – Primary consumer– Carnivores – Secondary , tertiary, quaternary

and so on

Symbiotic Relationships

• Not all relationships among organisms involve food

• Many live together and share resources in other ways

• 3 Examples– Mutualism– Commensalisms – Parasitism

• Mutualism – Relationship in which both organisms benefit

• Pollination by birds and insects• Transportation of seed by bird and other animals • Coral and Dinoflagellates • Ants and Aphids • Lichens – Alga supplies energy for itself and the

fungus, the fungus provides a protested space where it can grow

Lichen

Dinoflagellates

Coral

• Aphids are small, soft-bodied, near defenseless insects that feed on plant sap. They feed by inserting a pointed, strawlike mouth structure called a stylus into the vascular tissues (internal piping) of the plant and sucking the plant juices out. Plant sap, a combination of water and sugars, is low in other nutrients, however, and the aphid must process a great deal of plant sap in order to get the amino acids and other nutrients it needs. Most of the sugars and water, therefore, are excreted as waste through a pair of structures called cornicles located near the rearend of the insect. If you own a car and have parked it under a tree during the summer, the sticky sap you find on the car is likely to be the waste plant sap produced by aphids.

• Some ant species use this excess plant sap for their own nutrition. Ants find a colony of aphids and milk the waste plant sap from the cornicles. In return the ants protect the aphids from predators and parasites. In some cases ants tend colonies almost like ranchers with their cattle, not only protecting the aphids, but moving them around from plant to plant.

A remarkable 3-way mutualism appears to have evolved between an ant, a butterfly caterpillar, and an acacia in the American southwest. The caterpillars have nectar organs which the ants drink from, and the acacia tolerates the feeding caterpillars. The ants appear to provide some protection for both plant and caterpillar. Research of Diane Wagner, American Museum of Natural History Southwestern Research Station

• Commensalism – A symbiotic relationship in which one

organism benefits and the other is not affected

• Clownfish and a sea anemone• Remora and shark • Egret and Cattle / Horses

The relationship between these the sea anemone and the clownfish has been a much studied topic. As far as is known, the fish is able to produce a special mucus that causes the anemone not to release its stings. It is also believed that the movements of the fish inform the anemone of its identity. In return for the anemone's protection, the fish brings scraps to it, and lures larger fish into the anemone's tentacles.

• The egrets tended the cattle daily from soon after sunrise until late afternoon. The number of cattle egrets observed with each animal varied but commonly averaged two per animal. Egrets walked very near the cattle, picking insects from the animals and surrounding vegetation. They pecked horse flies and other nuisance flies from the cattle's lower extremities and regularly perched upon the animals backs to feed. The cattle did not appear belligerent nor disturbed by the presence of the egrets. In fact, the cattle apparently encouraged the egrets' association by moderating tail-switching and other "fly fighting" behavior while egrets were feeding on their backs.

Cattle Egrets

• A remora is a fish that has kind of a suction disk on the top of its head. By means of this disk, it attaches itself to some large sea animal, often a shark. The effect on the shark is probably neutral but the remora benefits. First it uses very little energy in moving about because it is carried by the shark. Secondly, it swallows pieces of the shark's prey that float by. This kind of relationship - in which one organism is benefited and the other is unaffected -

                                                

Imperial shrimp hitching a ride on a Sea-cucumber

Parasitism

• A symbiotic relationship when the host organism is harmed – Roundworms (Ascaris)– Flatworm (Tapeworm) – Lice– Ticks– Hookworm

Human Flea

Head Lice

Deer Tick

Can reach lengths of 25 meters

Tapeworm

http://www2.selu.edu/Academics/Faculty/wbond/nematodes/fum2

Hookworm