Transcript Ch. 12 - Blacklick Valley School District

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
Tree Frog
Orangutans
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 (-
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.
Musk Oxen
Snow Owl
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
Coral
Dinoflagellates
•
•
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 tailswitching 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
Tapeworm
Can reach lengths of 25 meters
Hookworm