Transcript Biomes and Populations

Succession
• What is ecological succession?
– Series of predictable changes that occur in a
community over time. Can be slow or caused by
sudden disturbance.
• What are the two types of ecological succession?
– Primary: when no soil is present (bare rock and
lava).
• First organism present = pioneer species
– Secondary: when soil is initially present.
Primary Succession
Succession - Marine Ecosystems
• In the deep ocean, succession can be spurred by:
– The disturbance caused by a dead whale falling to the
sea floor (“whale fall” community).
– Provides a food source to a normally barren location. A
series of scavengers and decomposers now have access
to this food source.
• How is this like primary succession?
• How is this like secondary succession?
Biomes
• What is a biome?
– An area of interacting ecosystems with similar
climate, soil type, and dominant organisms
(usually a plant species).
• What biome do we live in?
– Northwestern coniferous forest to temperate
grassland.
Major Land Biomes
Adaptation and Climate
• What is tolerance?
– Plants and animals are only adapted to a certain
range of “optimal” conditions.
– An organism’s ability to survive in areas outside
these optimal conditions is known as its
tolerance.
• What is an adaptation?
– An inherited trait that usually helps an organism
survive more successfully in its habitat.
Microclimates
• What is a microclimate?
– A small area within a biome that deviates from
overall climate patterns.
– Ex: It may be sunny a mile away, but rainy and
cold where you are.
Examples of Biomes
Biomes Summary
• There are ten major biomes.
• Keywords:
– Tropical Rain Forest:
• Canopy - leafy tops of trees
• Understory - second layer of shorter trees and vines
– Deciduous: a tree that sheds its leaves or needles each year.
– Coniferous: trees that produce seed-bearing cones and have
needles.
– Humus: nutrient-rich material on forest floor formed by decaying
leaves and other organic matter.
– Taiga: boreal forests
– Permafrost: permanently frozen subsoil in the Tundra biome.
Other Land Areas
• Mountain ranges
– Effect microclimate (ex: orographic rainfall)
– Vegetation changes as elevation changes
• Polar ice caps
– Cold all year and limited plant and algae growth
– Arctic = polar bears, seals, and insects
– Antarctic = penguins and marine mammals.
Aquatic Ecosystems
What are the main types?
Main Aquatic Ecosystems
• Freshwater
– Flowing-water
– Standing-water
– Wetlands
• Estuaries
• Marine
– Intertidal zone
– Coastal ocean
– Coral reefs
• Learning Target:
– Understand the importance of biodiversity in the biosphere.
• Language Objective:
– Describe an ecosystem’s biodiversity and what affects it using
terms such as endangered species, habitat fragmentation,
biological magnification, and invasive species.
Biodiversity
• What is biodiversity?
– Biological diversity/variety.
– Sum total of all genetically based variety of all
organisms in the biosphere.
• Why is it important?
– One of the greatest natural resources:
• Provides food, medicine, and industrial products
• Why would losing biodiversity be bad?
Willow tree, bark is the source of
the active compound in aspirin
Wheat, major food source
Rosy periwinkle, vincristine is a drug
derived from this plant used in the
treatments of cancers such as leukemia
Corn, used in food, ethanol
fuels, and natural plastics
Other Ways of Measuring
Diversity
• What is ecosystem diversity?
– Variety of habitats, communities, and processes in the living
world.
• What about species diversity?
– Number of different species in the biosphere (~1.7 million
species discovered so far).
– Varies between tropical zones (highest) to poles (lowest).
• Genetic diversity?
– Sum total of all different forms of genetic information carried
by every living organism on Earth.
– In a given species, this is all the different forms of genes
(units of heredity).
Changing Biodiversity
• How is biodiversity increased?
– New genetic variation is introduced in a species (ex:
mutations).
– New species.
– Better ecosystem = better chance of survival for more types
of organisms.
• How is it decreased?
– Genetic variation within a species decreases (ex: lots of
predation or disease).
– Species becomes extinct.
– Habitat is lost (ex: natural disaster or human influence).
Human Activity and Decreasing
Biodiversity
• Altering habitats.
– May destroy habitat or break an ecosystem up into
smaller pieces in a process called habitat
fragmentation (referred to as “biological islands”).
• Demand for wildlife products.
– Organism populations might be decreased to nearextinction (endangered species) or consumed until
none remain (extinction).
Habitat fragmentation
Pile of bison skulls (c. 1870); there were as
many as 40 million bison 200 years ago and by
the late 1800s there were less than 1,000.
Human Activity and Decreasing
Biodiversity
• Introduction of toxic compounds into food webs.
– Ex: DDT does not break down and can become concentrated
in higher trophic level organisms through biological
magnification.
• Introduction of foreign species to new environments
– Plants and animals are transported either on purpose or as
“hitch-hikers” during human migrations and travel.
– This increases the chance for invasive species.
– These organisms reproduce rapidly and can out-compete
local species without their normal diseases and predators.
• Learning Target:
– Understand the reasons for patterns in human
population growth and how this growth has affected
the biosphere.
• Language Objective:
– Apply the terms demography, demographic
transition, agriculture, ozone layer and depletion,
and global warming in your description of human
population growth and its effects on the biosphere.
Fishery Resources
• What do fisheries provide?
– Food source, products from fisheries can be used in a variety
of manufactured goods.
• What are the threats to fisheries?
– Overfishing: removing fish faster than can be replenished by
their reproduction.
– Fisheries were once considered a renewable resource, but if
overfished, the chance for fish to repopulate greatly
decreases.
• How are fisheries managed?
– Sustainable development practices include limits on industrial
fishing as well as aquaculture.
Air Resources
• Why is air important?
– It is where we get our oxygen, which is necessary for
our metabolism and survival.
• What is air quality?
– It is a way to describe the “health” of the air.
– Harmful materials called pollutants reduce air quality
(and also affect land and water resources) and can form
smog.
• What is acid rain?
– Pollutants from combustion, such as nitrogen and sulfur
compounds, gather in clouds and through chemical
reactions with water can produce nitric and sulfuric
acids.
Poor Air Quality
• Smog in Beijing, China.
Comes from factories,
automobiles, and homes.
• Stone erosion as a result
of acid rain. Very
corrosive.
Freshwater Resources
• Why is water important?
– Humans are 75-80% water: important for chemical
reactions and maintaining conditions in our bodies.
– Many organisms also rely heavily on water for the same
reasons.
• What are the dangers of untreated sewage?
– Disease, algal blooms, reduced quality of water.
• What can wetlands do?
– Plants and soils filter pollutants out of water as it moves
slowly through the wetland.
Resource Management
• Sustainable development in all resource usage
is important so those resources are present for
future generations.
• It is important to reduce environmental harm
when utilizing resources in order to have high
quality resources in the future as well.
Human Population Growth: Historical
Overview
Growth patterns
• What is demography?
– Scientific study of human populations.
– Looks at previous and current characteristics in
populations in order to predict future changes in that
population.
• What do demographers (those who study
demography) examine to predict future patterns?
– Birth rates and death rates (growth rate)
– Age structure
Demography
• Demographic
Transition:
– Dramatic change in birth
and death rates.
• Age Structure
Diagrams:
– Population profiles that
look at how many
individuals are in each age
group.
Growth and the Biosphere
• What caused the rapid growth of the human
population?
– First agriculture and cultivation methods provided
the resources necessary to maintain larger
populations.
– Then the industrial revolution made life easier by
providing food and goods quickly and efficiently. It
also was a time in which sanitation, medicine, and
access to healthcare increased.
– The green revolution also worked to increase
population by greatly increasing the world’s food
Growth and the biosphere
• Besides human population growth, what
was another side-effect of the industrial
revolution and urban development?
– Early industry did not have the same
regulations on pollutants, so pollutants entered
air, soil, and water.
– Urban centers (large cities with industry) still
tend to release a lot of pollutants into the
environment.
Growth and the biosphere
• What are some of the ways to reduce pollutants
from industry and urban centers?
– Sustainable development: utilizing resources in a
way that makes them renewable and high quality for
future generations.
• What has happened as result of pollution?
– Ozone layer depletion: ozone layer absorbs harmful
UV radiation; depletion means more can get through.
– Global climate change: often referred to as global
warming; greenhouse gases accumulate in the
atmosphere and can greatly affect global
temperatures.
Ozone Depletion and global
climate change
Importance of a
healthy biosphere
• Part of sustainable
development
• Taking care of what is
around us makes it so
those resources will be
there in the future.
• What can you do?
– Recycle, use alternate
energy sources, buy locally
grown foods, use less
water.
• Learning Target:
– Be able to distinguish renewable from nonrenewable
resources, how they affect populations, and how human
activity affects natural resources.
• Language Objective:
– Describe resources as renewable or nonrenewable and
describe the affects human activity have on those resources
using terms such as soil erosion, desertification,
deforestation, smog, and acid rain.
Renewable and Nonrenewable
Resources
How do we classify environmental resources?
What are the effects of human activity on these
resources?
Resources
• What are renewable resources?
– Can regenerate; usually living organisms or something that can be
replenished through biogeochemical cycles (nonliving).
– Although they can be replenished, they can become limited if not
managed.
• Examples of living renewable resources:
– Grass in a field, a tree in a forest, bear in the woods
• Examples of nonliving renewable resources:
– Carbon Cycle: carbon dioxide, carbohydrates.
– Nitrogen Cycle: ammonia, nitrate, nitrite.
– Phosphorus Cycle: phosphates.
• How are renewable resources maintained?
Resources
• What are nonrenewable resources?
– Something that cannot be regenerated through
natural processes; once it is used, the resource
will not be replenished.
– Examples of nonrenewable resources:
• Coal, oil, natural gas (nonliving).
• A forest that is clear-cut will not be able to grow
back unless replanted by humans; can change the
ecosystem permanently.
Resources
• What are some of the resources humans rely on and
what are they used for?
– Land: soil for agriculture, building and living space, raw
materials.
– Forests: wood (paper, building supplies, heating, power),
ecological functions (place to live, create oxygen).
– Fisheries: food source.
– Air: where we get our oxygen.
– Freshwater: used for drinking, crops, and in industry.
Land Resources
• Soil is a major land resource. When is it
renewable?
– Like any renewable resource, when it is well-managed
it will remain renewable.
– If not well-managed, soil can become permanently
damaged.
• How is soil maintained?
– Plant roots keep soil in place; plowing, overgrazing,
and deforestation removes those plants and can lead to
soil erosion and eventually desertification.
Without Management
Sahara Desert, expands ~0.6
km/yr. Rapid expansion started
after draught, lasting from
1968-1973.
Covers 3,630,000 sq. miles.
American mid-west during the Great Depression
(c. 1930). Poor agricultural practices led to
extreme soil erosion that lasts through to today,
resulting in the loss of 47 metric tons of topsoil
per hectare per year (~27,000 lbs/sq. mile = ~170
freshman per square mile).
Land Resources
• Good topsoil is fertile
(contains humus) and is
able to absorb and retain
moisture while still
allowing excess water to
drain.
• Soil also works to filter
groundwater, making it
suitable to drink.
Forest Resources
• What is the difference between old-growth forest
and other types of forest?
– Old-growth has never before been logged. Species
composition in logged forests can be different from prelogging conditions.
– Old-growth forests are often considered nonrenewable
because it takes hundreds of years to replace them.
Managing Forests
• What is deforestation?
– When forests are lost.
• What does deforestation also affect?
– This has an affect on land resources as well because trees
help hold soil in place. Without these trees, soil erosion
is more likely to occur.
• How do people manage forests?
– Replanting and regrowth programs for after logging is
done, as well as logging trees that promote the growth of
new trees. Genetic alteration is also a factor, as it might
produce trees that grow faster AND are high-qualtiy.
Deforestation
• This can have a drastic
affect on organisms as
well as soil quality
• Estuary in Madagascar
after deforestation. Brown
area is water that is filled
with sediment.
Fishery Resources
• What do fisheries provide?
– Food source, products from fisheries can be used in a variety
of manufactured goods.
• What are the threats to fisheries?
– Overfishing: removing fish faster than can be replenished
by their reproduction.
– Fisheries were once considered a renewable resource, but if
overfished, the chance for fish to repopulate greatly
decreases.
• How are fisheries managed?
– Sustainable development practices include limits on
industrial fishing as well as aquaculture.
Air Resources
• Why is air important?
– It is where we get our oxygen, which is necessary for our
metabolism and survival.
• What is air quality?
– It is a way to describe the “health” of the air.
– Harmful materials called pollutants reduce air quality (and also
affect land and water resources) and can form smog.
• What is acid rain?
– Pollutants from combustion, such as nitrogen and sulfur
compounds, gather in clouds and through chemical reactions with
water can produce nitric and sulfuric acids.
– Acid rain can alter soil chemistry and harm organisms.
Poor Air Quality
• Smog in Beijing,
China. Comes from
factories, automobiles,
and homes.
• Stone erosion as a
result of acid rain.
Very corrosive
Freshwater Resources
• Why is water important?
– Humans are 75-80% water: important for chemical
reactions and maintaining conditions in our bodies.
– Many organisms also rely heavily on water for the same
reasons.
• What are the dangers of untreated sewage?
– Disease, algal blooms, reduced quality of water.
• What can wetlands do?
– Plants and soils filter pollutants out of water as it moves
slowly through the wetland.
Resource Management
• Sustainable development in all resource usage
is important so those resources are present for
future generations.
• It is important to reduce environmental harm
when utilizing resources in order to have high
quality resources in the future as well.