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Unit 5
What is Ecology and How is it Impacted by Human?
What is Ecology?
Ecology
These interactions determine ___________________ of organisms and their __________________________
For example
The rediscovery of the nearly extinct harlequin toad in Costa Rica raises many ecological questions
What environmental factors limit their geographic distribution?
What factors (food, pathogens) affect population size?
The Scope of Ecological Research
Ecologists work at levels ranging from ___________________ organisms to the ___________________
Global Ecology
The __________________ is the global ecosystem, the sum of all the planet’s ecosystems
______________________ ecology examines the influence of energy and materials on organisms across
the biosphere Landscape Ecology
A ______________________ or ___________________ is a mosaic of connected ecosystems
_________________________ ecology focuses on the exchanges of energy, materials, and organisms
across multiple ecosystems
Ecosystem Ecology
An ______________________ is the community of organisms in an area and the physical factors with
which they interact
Ecosystem ecology emphasizes energy flow and chemical cycling among the various ___________ and
__________________ components
Community Ecology
A _______________________ is a group of populations of different species in an area
________________________ ecology deals with the whole array of interacting species in a community
Population Ecology
A __________________ is a group of individuals of the same species living in an area
__________________ ecology focuses on factors affecting population ___________ over time
Organismal Ecology
____________________ ecology studies how an organism’s structure, physiology, and (for animals)
behavior meet environmental challenges
With this heirarchy you will note that all areas of biology discussed this semester is integrated in ecological
studies
For example,
Ecologists ask questions about where species occur and why species occur where they do?
How do environmental factors explain distribution of organisms?
Both _________________ and ___________________ factors influence species distribution
For example, climate, interspecific interactions, and other factors affect the distribution of the red kangaroo
Biotic Factors
Biotic factors that affect the distribution of organisms may include
_______________________
_______________________
For example, sea urchins can limit the distribution of seaweeds
_______________________
Abiotic Factors
Abiotic factors affecting distribution of organisms include
_________________________
Cells may freeze and rupture below 0°C, while most proteins denature above 45°C
_____________________ and ______________________
desert vs rainforest; deep vs shallow
_____________________
_____________________
_____________________
_________________ and _____________________
Limit vegetation thus limits animals
Most abiotic factors vary in space and time
What is Population Ecology?
Population ecology is
Density, Dispersion Patterns and Demographics are Important Population Variable
A ______________________ is a group of individuals of a single species living in the same general area
Populations are described by their _____________________ and ___________________
Density
Density is
In most cases, it is impractical or impossible to count all individuals in a population
Population size can be estimated by either extrapolation from small samples, an index of population
size (e.g., number of nests), or the __________________________________
___ = # of individuals captured tagged and released in first sample
___ = # of individuals capture in 2nd sample
___ = # of recapures in 2nd sample
___ = population size
Density is the result of an interplay between processes that add individuals to a population and those
that remove individuals
___________________________ is the influx of new individuals from other areas
___________________________ is the movement of individuals out of a population
Patterns of Dispersion
Dispersion is
Within a population’s geographic range, local densities may vary greatly
The __________________ pattern of a population refers to the way individuals are spaced within their area
Dispersion patterns can be
Clumped
In a _______________ pattern individuals are grouped in __________________
Uniform
In a ____________ pattern individuals are equally spaced in the environment
It may be influenced by social interactions such as ___________________, the defense of a bounded
space against other individuals
Random
In a ____________________ pattern of dispersion, the individuals in a population are spaced in an
unpredictable way
Demography
Demography is
Death rates and birth rates are of particular interest to demographers
Life Tables
A ____________________________ is an age-specific summary of the survival pattern of a population
It is best made by following the fate of a _______________, a group of individuals of the same age
The life table of Belding’s ground squirrels reveals many things about this population
For example, it provides data on the proportions of males and females alive at each age
Survivorship Curves
A survivorship curve is
The survivorship curve for Belding’s ground squirrels shows a relatively constant death rate
Survivorship curves can be classified into three general types
_________________________: low death rates during early and middle life, then an increase in death rates
among older age groups
_________________________: the death rate is constant over the organism’s life span
_________________________: high death rates for the young, then a slower death rate for survivors
Reproductive Rates
For species with sexual reproduction, demographers often concentrate on females in a population
A reproductive table, or fertility schedule, is
It describes __________________________________________ of a population
How do Populations Grow?
Exponential Growth
Exponential population growth is
Under these conditions, the rate of increase is at its _________________________, denoted as rmax
The equation of exponential population growth is
Exponential population growth results in a ___________________________curve
The J-shaped curve of exponential growth characterizes some rebounding populations
For example, the elephant population in Kruger National Park, South Africa, grew exponentially
after hunting was banned
Does this type of growth typify what truly happens in nature?
The logistical model describes how a population grows more ____________ as it nears its carrying capacity
Exponential growth _____________________ be sustained for long in any population
A more realistic population model _______________ growth by incorporating ____________________
Carrying capacity (K) is
Carrying capacity __________________ with the abundance of ______________ _______________
The Logistical Growth Model
In the logistic population growth model, the per capita rate of increase declines as ________________
is reached
The logistic model starts with the exponential model and adds an expression that reduces per capita
rate of increase as N approaches K
The logistic model of population growth produces a sigmoid (_____________________) curve
The Logistical Model and Real Populations
The growth of laboratory populations of paramecia fits an ______________________ curve
These organisms are grown in a constant environment lacking predators and competitors
Some populations overshoot ____ before settling down to a relatively stable density
Some populations fluctuate greatly and make it difficult to define______
Some populations show an Allee effect, in which individuals have a more difficult time surviving or
reproducing if the population size is too small
The logistic model fits few ________ populations but is useful for ____________________ possible
growth
Conservation biologists can use the model to estimate the critical size below which populations may
become extinct
What causes populations size to be regulated?
Many factors that regulate population growth are ________________________________
There are two general questions about regulation of population growth
What environmental factors stop a population from growing indefinitely?
Why do some populations show radical fluctuations in size over time, while others remain stable?
Population Change and Population Densisty
In ____________________________________ populations, birth rate and death rate do not change with
population density
Abiotic factors may reduce population size before other limiting factors become important
In ____________________________________ populations, birth rates fall and death rates rise with
population density
Mechanisms of Density-Dependent Population Regulation
Density-dependent birth and death rates are an example of _____________________________ that
regulates population growth
Density-dependent birth and death rates are affected by many factors, such as
Competition for ________________________
In crowded populations, increasing population density intensifies competition for resources and
results in a __________________ birth rate
____________________________
_________________________ of toxic wastes can contribute to density-dependent regulation of
population size
_________________________
As a prey population builds up, predators may feed preferentially on that species
________________________ Factors
For some populations, _______________ (physiological) factors appear to regulate population size
________________________
In many vertebrates and some invertebrates, competition for territory may limit density
___________________________
Population density can influence the health and survival of organisms
In dense populations, pathogens can spread more __________________
Mechanisms of Density Independent Population Regulation
Life history traits impact populations
An organism’s ____________________ comprises the traits that affect its schedule of reproduction
and survival
The _______________ at which reproduction begins
How _______________ the organism reproduces
How _________________ offspring are produced during each reproductive cycle
Life history traits are evolutionary outcomes reflected in the development, physiology, and
behavior of an organism
“Trade-offs” and Life Histories
Organisms have finite resources, which may lead to ____________________between survival and
reproduction
For example, there is a trade-off between survival and paternal care in European kestrels
Some plants produce a large number of small seeds, ensuring that at least some of them
will grow and eventually reproduce
Other types of plants produce a moderate number of large seeds that provide a large store
of energy that will help seedlings become established
__________________, or density-dependent selection, selects for life history traits that are sensitive
to population density
Populations ________ reproductive rate, therefore higher parental care
__________________, or density-independent selection, selects for life history traits that maximize
reproduction
Populations have a ____________ reproductive rate
The concepts of K-selection and r-selection are oversimplifications but have stimulated
alternative hypotheses of life history evolution
Population Dynamics
The study of ___________________________ focuses on the complex interactions between biotic and
abiotic factors that cause variation in population size
Most populations fluctuate in numbers
Some populations have “______________________________” cycles
Some populations ______________________ in density with regularity
Boom-and-bust cycles
Why does the hare population get much higher than the lynx?
The Global Human Population
The human population increased relatively slowly until about 1650 and then began to grow exponentially
But can earth sustain this growth rate?
How does the Ecology of Community differ from that of a Population?
Communities in Motion
A biological community is
For example, the “carrier crab” carries a sea urchin on its back for protection against predators
Interspecific interactions are fundamental to community structure
Relationships with other species in the community are called ____________________________________
Interspecific interactions can affect the survival and reproduction of each species, and the effects can be
summarized as positive (+), negative (–), or no effect (0)
__________________________
_________________________ competition (–/– interaction) occurs when species compete for a resource in
short supply
_________________________ competition?
Which type of competition is more challanging to an individual?
Ecological Niches
The total of a species’ use of biotic and abiotic resources is called the species’ ____________________
An ecological niche can also be thought of as an organism’s ____________________________
What are the outcomes of interspecific competition?
______________________________________
Strong competition can lead to competitive exclusion, local elimination of a ______________________
The competitive exclusion principle states that two species competing for the same limiting resources
cannot coexist in the same place
______________________________________
Resource partitioning is
______________________________________
__________________________ (+/– interaction) refers to interaction where one species, the predator, kills
and eats the other, the prey
Prey adapt using protective strategies
_____________________________________
____________________________ (+/– interaction) refers to an interaction in which an herbivore eats parts
of a plant or alga
It has led to evolution of plant mechanical and chemical defenses and adaptations by herbivores
_____________________________________
Symbiosis is a relationship where
Examples are
________________________________________
In ___________________ (+/– interaction), one organism, the ____________________, derives
nourishment from another organism, its ________________, which is harmed in the process
Endoparasite vs Ectoparasite?
Many parasites have a complex life cycle involving a number of hosts
Some parasites change the behavior of the host to increase their own fitness
_________________________________________
Mutualistic symbiosis, or ______________________ (+/+ interaction), is an interspecific interaction
that benefits both species
A mutualism can be
_________________, where one species cannot survive without the other
_________________, where both species can survive alone
_________________________________________
In commensalism (+/0 interaction), one species benefits and the other is neither harmed nor helped
Commensal interactions are hard to document in nature because any close association likely affects both
species
__________________________________
Facilitation (/ or 0/) describes an interaction where one species can have positive effects on another
species without direct and intimate contact
For example, the black rush makes the soil more hospitable for other plant species by removing salt in soil
Divestiy and trophic structure characterize biological communities
In general, a few species in a community exert strong control on that community’s structure
Two fundamental features of community structure are _______________________ and
______________________________________
Species Diversity
Species diversity of a community is the ________________ of organisms that make up the community
It has two components: species richness and relative abundance
________________________________ is the total number of different species in the community
________________________________ is the proportion each species represents of the total individuals
in the community
Two communities can have the same species richness but a different relative abundance
Diversity can be compared using a diversity index
__________________________________ index
Diversity and Community Stability
Ecologists manipulate diversity in experimental communities to study the potential benefits of diversity
For example, plant diversity has been manipulated at Cedar Creek Natural History Area in Minnesota
for two decades
Communities with higher diversity are
_______________________ productive and more stable in their productivity
_______________________ able to withstand and recover from environmental stresses
More resistant to ___________________________, organisms that become established outside their
native range
Trophic Structure
________________________________ is the feeding relationships between organisms in a community
It is a key factor in community _____________________
___________________________ link trophic levels from producers to top carnivores
Food Webs
A ________________________ is a branching food chain with complex trophic interactions
Species with a Large Impact
Certain species have a very large impact on community structure
Dominant Species
Dominant species are those that are most _________________ or have the highest _______________
Dominant species exert powerful control over the occurrence and distribution of other species
One hypothesis suggests that dominant species are most competitive in exploiting resources
Another hypothesis is that they are most successful at avoiding predators
Keystone Species
__________________________ exert strong control on a community by their ecological roles, or niches
In contrast to dominant species, they are not necessarily abundant in a community
Field studies of sea stars illustrate their role as a keystone species in intertidal communities
Observation of sea otter populations and their predation shows how otters affect ocean communities
Ecosystem Engineers
__________________________ (or “foundation species”) cause physical changes in the environment
that affect community structure
What makes up an Ecosystem?
Ecosystem ecology emphasizes ____________________ flow and _______________________ cycling
Ecosystem
Components of ecosystems
Energy flow
Chemical cycling
Let’s first focus on Energy Flow
A terrarium has the components of an ecosystem
Primary production sets the energy ______________________ for ecosystems
Primary production
The amount of solar energy __________________________ to chemical energy
Carried out by _______________________
Produces _______________________________
Amount of living organic material in an ecosystem
Primary production of different ecosystems
Energy supply ____________________________ the length of food chains
A pyramid of production
Illustrates the cumulative loss of energy transfer in a _______________________________
Chemicals are cycled between organic matter and abiotic reservoirs
Ecosystems are supplied with a continual influx of ___________________________
Sun and Earth’s interior
Life also depends on the _______________________________ of chemicals
Organisms acquire chemicals as nutrients and lose chemicals as waste products
Biogeochemical cycles
Cycle chemicals between ______________________ and the _______________________
What are some examples?
The _____________________ Cycle
Water is essential to all organisms
The _____________________ Cycle
Carbon-based organic molecules are essential to all organisms
The _____________________ Cycle
Nitrogen is a component of amino acids, proteins, and nucleic acids
The _____________________ Cycle
Phosphorus is a major constituent of nucleic acids, phospholipids, and ATP
What is the Biosphere?
The biosphere is the
Earth’s _____________________ dictates the organization of the ecosystems that make up the biosphere
Earth’s climate varies by latitude and season and is changing rapidly
The long-term prevailing weather conditions in an area constitute its _______________________
Four major abiotic components of climate are
What controls each?
Global Climate Patterns
Global climate patterns are determined largely by __________________ energy and the planet’s
movement in ______________________
The warming effect of the sun causes temperature variations, which drive evaporation and the
circulation of air and water
This causes latitudinal variations in climate
Regional and Local Effects on Climate
Climate is affected by seasonality, large bodies of water, and mountains
The structure and distribution of terrestrial biomes are controlled by climate and disturbance
__________________________ are major life zones characterized by vegetation type (terrestrial biomes) or
physical environment (aquatic biomes)
Climate is very important in determining why terrestrial biomes are found in certain areas
Climate and Terrestrial Biomes
Climate affects the ____________________________ patterns of terrestrial bones
A _________________________ plots the temperature and precipitation in a region
Biomes are affected not just by average temperature and precipitation, but also by the pattern of temperature
and precipitation through the year
Distrubance and Terrestrial Biomes
________________________ is an event such as a storm, fire, or human activity that changes a community
For example, frequent fires can kill woody plants and maintain the characteristic vegetation of a savanna
For example, fires and outbreaks of pests create gaps in forest that allow different species to grow
Fire suppression has changed the vegetation of the Great Plains
Terrestrial Biomes
Terrestrial biomes can be characterized by
_____________________________
Several types of ___________________________ occur in the warm, moist belt along the equator
In tropical _________ forests, rainfall is relatively constant, while in tropical _________ forests
precipitation is highly seasonal
Temperature is high year-round (25–29C) with little seasonal variation
Tropical forests are home to millions of animal species, including an estimated 5–30 million still
undescribed species of insects, spiders, and other arthropods
______________________________
Equatorial and subequatorial regions
___________________________ precipitation is seasonal
Temperature is warm year-round (24–29C) but more seasonally variable than the tropics
Grasses and forbs make up most of the ground cover
The dominant plant species are fire-adapted and tolerant of seasonal drought
Common inhabitants include insects and mammals such as wildebeests, zebras, lions, and hyenas
Fires set by humans may help maintain this biome
____________________________
__________________ occur in bands near 30C north and south of the Equator, and in the interior of
continents
Precipitation is low and highly variable, generally less than 30 cm per year
Deserts may be hot or cold
Desert plants are adapted for heat and desiccation tolerance, water storage, and reduced leaf surface area
Common desert animals include many kinds of snakes and lizards, scorpions, ants, beetles, migratory
and resident birds, and seed-eating rodents; many are nocturnal
Ubanization and irrigated have reduced the natural biodiversity of some deserts
_____________________________
__________________________ occurs in midlatitude coastal regions on several continents
Precipitation is highly seasonal with rainy winters and dry summers
Summer temperature is hot (30C+) while fall, winter, and spring
The chaparral is dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to fire
and drought
Animals include amphibians, birds and other reptiles, insects, small mammals and browsing mammals
Humans have reduced chaparral areas through agriculture and urbanization
_________________________________________
___________________________________________ are found on many continents
Precipitation is highly seasonal
Winters are cold (often below –10C) and dry, while summers are hot (often near 30C) and wet
The dominant plants, grasses and forbs, are adapted to droughts and fire
Native mammals include large grazers such as bison and wild horses and small burrowers such as prairie
dogs
Most grasslands have been converted to farmland
__________________________________________
____________________________________________ is found at midlatitudes in the Northern
Hemisphere, with smaller areas in Chile, South Africa, Australia, and New Zealand
Significant amounts of precipitation fall during all seasons as rain or snow
Winters average 0C, while summers are hot and humid (near 35C)
Vertical layers are dominated by deciduous trees in the Northern Hemisphere and evergreen eucalyptus
in Australia
Mammals, birds, and insects make use of all vertical layers in the forest
In the Northern Hemisphere, many mammals hibernate in the winter
These forests have been heavily settled on all continents, but are recovering in places
______________________________________
The _______________________________________, or ________________, spans northern North
America and Eurasia and is the largest terrestrial biome on Earth
Precipitation varies; some have periodic droughts and others, especially near coasts, are wet
Winters are cold and long while summers may be hot (e.g., Siberia ranges from –50C to 20C)
Conifers such as pine, spruce, fir, and hemlock dominate
The conical shape of conifers prevents too much snow from accumulating and breaking their branches
Animals include migratory and resident birds, and large mammals such as moose, brown bears, and
Siberian tigers
Some forests are being logged at an alarming rate
_________________________________
_________________________________ covers expansive areas of the Arctic; alpine tundra exists on
high mountaintops at all latitudes
Precipitation is low in arctic tundra, and higher in alpine tundra
Winters are long and cold (below –30C) while summers are relatively cool (less than 10C)
____________________________, a permanently frozen layer of soil, prevents water infiltration
Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) and supports birds,
grazers, and their predators
Aquatic Biomes are diverse and dynamic systems that cover most of Earth
Aquatic biomes fall into two categories
________________________
Marine biomes have salt concentrations of about 3%
Take up about 75% of Earth’s surface
________________________
Freshwater biomes have salt concentrations of <0.1%
Freshwater biomes are closely linked to soils and the biotic components of the surrounding terrestrial
biome
Zonation in Aquatic Biomes
Many aquatic biomes are stratified into zones or layers defined by
The upper _______________ zone has sufficient light for photosynthesis while the lower ___________
zone receives little light
The photic and aphotic zones combined makes up the ____________________ zone
Deep in the aphotic zone lies the __________________ zone with a depth of 2,000 to 6,000 m
The organic and inorganic sediment at the bottom of all aquatic zones is called the _____________ zone
The communities of organisms in the benthic zone are collectively called the _________________
__________________________, dead organic matter, falls from the productive surface water and is an
important source of food
In oceans and most lakes, a temperature boundary called the _____________________ separates the
warm upper layer from the cold deeper water
Many lakes undergo a semiannual mixing of their waters called _______________
Turnover mixes oxygenated water from the surface with nutrient-rich water from the bottom
Aquatic Biomes
Major aquatic biomes can be characterized by their physical environment, chemical environment, geological
features, photosynthetic organisms, and heterotrophs
Lakes
Size varies from small ponds to very large lakes
Two categories of lakes
_______________________________ lakes
are nutrient-poor and generally oxygen-rich
_______________________________ lakes
are nutrient-rich and often depleted of oxygen if ice covered in winter
Two additional zones associated with lakes only
____________________________ zone
Primarily deep areas with small drifting animals called zooplankton graze on the phytoplankton
____________________________ zone
Well lit shallow areas with rooted and floating plants
Wetlands
A ____________________ is a habitat that is inundated by water at least some of the time and that
supports plants adapted to water-saturated soil
Wetlands are among the most productive biomes on Earth
Humans have destroyed up to _____% of wetlands; wetlands purify water and reduce flooding
Streams and Rivers
The most prominent physical characteristic of streams and rivers is ___________________
Rivers are divided into Headwaters (source of river and usually called streams) and Downstream water
_________________________ are generally cold, clear, turbulent, swift, and oxygen rich; they are
often narrow and rocky
_____________________________________ form rivers and are generally warmer, more turbid,
and more oxygenated; they are often wide, meandering, and have silty bottoms
Estuaries
An ________________________ is a transition area between river and sea
Salinity varies with the rise and fall of the tides
Estuaries are nutrient rich and highly productive
Estuaries include a complex network of tidal channels, islands, natural levees, and mudflats
An abundant supply of food attracts marine invertebrates, fish, waterfowl, and marine mammals
Intertidal Zone
An _________________________ zone is the area between the highest high tide and lowest low tide
therefore, organisms are challenged by variations in temperature and salinity and by the mechanical
forces of wave action
Oxygen and nutrient levels are high with rocky or sandy substrate
Oceanic Pelagic Biome
The _________________________________is constantly mixed by wind-driven oceanic currents
Oxygen levels are _____________
Turnover in temperate oceans is important
This biome covers approximately 70% of Earth’s surface
Phytoplankton and zooplankton are the dominant organisms in this biome
Coral Reefs
_______________________ are formed from the calcium carbonate skeletons of corals (cnidarians)
Shallow reef-building corals lie in the photic zone in clear water about 20–30C; deep sea corals live at
200–1,500 m
Corals require high ________ and a __________________ substrate for attachment
Marine Benthic Zone
The marine benthic zone consists of the seafloor below the surface waters of the coastal, or _________,
zone and the offshore pelagic zone
Organisms in the very deep benthic (abyssal) zone are adapted to continuous cold and extremely high
water pressure
Substrate is mainly soft sediments; some areas are rocky
Shallow areas contain seaweeds and filamentous algae
Deep-sea hydrothermal vents of volcanic origin on mid-oceanic ridges are surrounded by unique
chemoautotrophic prokaryotes, as well as echinoderms and arthropods
Neritic benthic communities include invertebrates and fishes
Overfishing and dumping of waste have depleted fish populations
How can the study of biology help conserve the ecosystems of the biosphere?
Conservation Biology
Scientists have named and described 1.8 million species and they estimate 10–200 million species exist on
Earth
Humans are rapidly pushing many species toward extinction
___________________________ biology, which seeks to preserve life, integrates several fields
Human activities threaten Earth’s biodiversity
Rates of species extinction are difficult to determine under natural conditions
The high rate of species extinction is largely a result of ecosystem degradation by humans
Humans are threatening Earth’s biodiversity
Three Levels of Biodiversity
Biodiversity has three main components
_____________________________________
Genetic diversity comprises genetic variation within a population and between populations
What happens to an population if there is no genetic diversity and the environment is selecting for a
trait that is not in existence?
_____________________________________
Species diversity is the variety of species in an ecosystem or throughout the biosphere
According to the U.S. Endangered Species Act
An _________________________ species is “in danger of becoming extinct throughout all or a
significant portion of its range”
A __________________________ species is likely to become endangered in the foreseeable
future
Conservation biologists are concerned about species ________________ because of alarming
statistics regarding extinction and biodiversity
Globally, 12% of birds, 20% of mammals, and 32% of amphibians are threatened with extinction
Extinction may be local or global
_____________________________________
Human activity is reducing ecosystem diversity, the variety of ecosystems in the biosphere
More than 50% of wetlands in the contiguous United States have been drained and converted to
other ecosystems
Why is Ecosystem Diversity Important?
Ecosystem Services
______________________________ encompass all the processes through which natural ecosystems
and their species help sustain human life
Some examples of ecosystem services
Purification of air and water
Detoxification and decomposition of wastes
Cycling of nutrients
Moderation of weather extremes
Biodiversity and Human Welfare
Human biophilia allows us to recognize the value of biodiversity for its own sake
Species diversity brings humans practical benefits
Threats to Biodiversity
Most species loss can be traced to four major threats
____________________________________
Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere
In almost all cases, habitat fragmentation and destruction lead to loss of biodiversity
For example
_______________________________________
______________________ species are those that humans move from native locations to new
geographic regions
Without their native predators, parasites, and pathogens, introduced species may spread rapidly
Introduced species that gain a foothold in a new habitat usually disrupt their adopted community
_____________________________________
Overharvesting is human harvesting of wild plants or animals at rates exceeding the ability of
populations of those species to rebound
Large organisms with low reproductive rates are especially vulnerable to overharvesting
For example, elephant populations declined because of harvesting for ivory
DNA analysis can help conservation biologists identify the source of illegally obtained animal
products
For example, DNA from illegally harvested ivory can be used to trace the original population
of elephants to within a few hundred kilometers
__________________________________________
Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems
Pollution of the environment compounds our impact on other species
The global water cycle can transport pollutant
Pollutants in a food chain can lead to _________________________________________
Nutrient pollution from fertilizer and wastes
Linked to summer “dead zone” in the Gulf of Mexico
Gradually thinning _________________________ layer
Release of chlorofluorocarbons from aerosol cans and manufacturing
Rapid warming is changing the global climate
The scientific debate about global warming is over
Global temperature has risen
0.8°C in the last 100 years
0.6°C of that increase occurred in the last three decades
2 to 4.5°C increases are likely by the end of the 21st century
Global warming most evident in arctic
Shrinking sea ice
Thinning ice sheets
Melting permafrost
What is the proof
Atmospheric CO2 did not exceed 300 ppm for 650,000 years
Atmospheric CO2 is approximately 385 ppm today
High levels of methane and nitrous oxide also trap heat
What exactly is Global Warming?
Global climate change affects biomes, ecosystems, communities, and populations
Terrestrial biomes determined by temperature and rainfall
Changing as a consequence of global warming
Distributions of populations and species also changing
Disappearance of many species being caused by changing climate
Climate change affects seasonal events in some plants and animals
Conservation Biology and Restoration Ecology
Protecting endangered populations is one goal of conservation biology
Habitat loss
Population _____________________________
A harmful effect of habitat loss
Splitting and isolation of portions of populations
Can lead to extinctions
Sustaining ecosystems and landscapes is a conservation priority
Conservation biology priority
Past efforts
Saving individual species
Today
Biodiversity of ecosystems
______________________________ ecology
Dynamics of a collection of ecosystems
Edges can fragment ecosystems
Fragmentation is corrected with ______________________________________
Protected areas are established to slow the loss of biodiversity
Conservation biology focuses on _____________________________________________
Have a large number of endangered and threatened species
Have a concentration of _____________________________________
Hot spot designation favors the most noticeable organisms
Sustainable development is an ultimate __________________________
Biosphere is made of complex interconnections
Sensible decisions needed to conserve these networks
Must work for a sustainable future
Sustainable development depends on continued research and application