conservation biology
which seeks to preserve life, integrates several fields: Ecology, Evolutionary biology, Molecular biology, Genetics, and Physiology
extinction
is the natural phenomenon that has been occurring since life first evolved, high rates of extinction though is responsible for biodiversity crisis (we can oly estimate the number of species currently existing we cannot determine exact rate of species loss
levels of biodiversity
it is biological diversity; genetic diversity, species diversity, and ecosystem diversity
genetic diversity
comprises genetic variation within a population and also genetic variation between populations that is associated with adaptions to local conditions, if one pop becomes extinct then a species may have lost some of the genetic diversity that makes microev
species diversity
the variety of species in an ecosystem or across the biosphere, as species are lost to extinction species diversity decreases
endangered species
in danger of becoming extinct throughout all or a significant portion of its range
threatened species
is likely to become endangered in the near future
ecosystem diversity
Human activity is reducing ecosystem diversity, it is the variety of ecosystems in the biosphere, The local extinction of one species can have a negative impact on other species in an ecosystem
biophilia
our sense of connection to nature and all life, allows us to recognize the value of biodiversity for its own sake
species and genetic diversity bennifits
Species diversity brings humans practical benefits: The loss of species also means loss of unique genes and genetic diversity
The enormous genetic diversity of organisms has potential for great human benefit
ecosystem services
encompass all the processes through which natural ecosystems help sustain human life (ex:Some examples of ecosystem services
Purification of air and water
Detoxification and decomposition of wastes
Crop pollination, pest control, and soil preservation) (f
threats to bidoiversity
happens on local, regional, and global scales. 4 types: habitat loss, introduced species, overharvesting, and global change
habitat loss
human alteration of habitats is single greatest threat to biodiversity throughout the biosphere, has been brought about by argiculture, urban developement, forestry, mining, and pollution, when no alternative habitat is available or species is unable to m
introduced species
also called exotic species are those that humans move intentionally or accientally from the species native locations to new geographic locations, Without their native predators, parasites, and pathogens, introduced species may spread rapidly, Introduced s
overharvesting
is humans harvesting of wild organisms (p or a) at rate exceeding the ability of their populations of those species to rebound, Species with restricted habitats or large body size with low reproductive rates are especially vulnerable to overharvesting. so
global change
alters the fabric of earths ecosystem and regional to global scales; Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems that reduce the capicity of earth to sustain life
Biologists focusing on conservation at the population and species levels follow two main approaches
The small-population approach and The declining-population approach
small population approach
The small-population approach studies processes that can make small populations become extinct (processes that causes extinctions once population size have been reduced), Small populations and low genetic diversity do not always lead to extinction, emphis
extinction vortex
Is a downward population spiral in which inbreeding and genetic drift combine to cause a small population to shrink and (unless the spiral is reversed) become extinct (A small population is vulnerable to inbreeding and genetic drift, which draw the popula
genetic variation loss
inbreeding and genetic drift cause loss of genetic variation and there effects become more harmful as population shrinks; inbreeding reduces fitness because offspring are more liekly to be homozygous for harmfu ressive traits
miminmum viable population (MVP)
is the minimum population size at which a species can survive, depends on factors that affect a population's chances for survival over a particular time (before it starts down extintion vortex)
effective population size
based on the breeding potential of the popilation (A meaningful estimate of MVP requires determining the effective population size, which is based on the population's breeding potential; cuz some dont breed or pass on the good traits), Conservation progra
Declining population approach
Emphasizes the environmental factors that caused a population to decline in the first place, focueses on threatened and endangered populations that show a downward trend even if the population is far above the MVP
conservation of species
Conserving species often requires resolving conflicts between habitat needs of endangered species and human demands, The ecological role of the target species is an important consideration in conservation
global change.
Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems, alters the fabric of earths ecosystem at regional to global scale
defining features of landscapes
The boundaries, or edges, between ecosystems are defining features of landscapes (ex: lake and the surrounding forest or between cropland and suburban housing tracts)
edge
own set of physical conditions (mixture of both conditions), Some species take advantage of edge communities to access resources from both adjacent areas
fragmentation
Landscapes dominated by fragmented habitats support fewer species due to a loss of species adapted to habitat interiors, but supports growth of species that live in fragmentated area, reduced biodiversity and a preponderance of edge adapted species
movement corroidors
is a narrow strip or series of small clumps of habitat connecting otherwise isolated patches (in fragment habitat), is extremely important for conserving biodiversity, In areas of heavy human use, artificial corridors are sometimes constructed
Positive: M
protecting areas
to slow biodiversity loss. choosing what area to protect biologists focus on biodiversity hot spot; is a relativly small area with numerous endemic species (species found nowhere else in the world) and a large number of endangered and threatened species,
nature reservues
are biodiversity islands in a sea of habitat degraded by human activity
zoned reserves
extensive region that includes relatively undisturbed areas surrounded by areas that have been changed by human activity and are used for economic gain, key challange is to devlop a social and economic surrounding lands that is compatable with all the lo
enviromental change that threatens biodiversity/ Human-caused changes in the environment include
nutrient enrichment, toxin accumulation, and climate change
critical load
is the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity
nitrogen enrichment
After vegetation is cleared from an area the existing reserve on nutrients in the soil is only available for a brief time (since the substantial fraction of these nutrients is exported from the area in crop biomass) and so farmers add fertilizer to increa
toxins in the enviroment
Humans release many toxic chemicals, including synthetics previously unknown to nature
In some cases, harmful substances persist for long periods in an ecosystem
One reason toxins are harmful is that they become more concentrated in successive trophic lev
biological magnification
the process in which retained substances become more concentrated at each higher trophic level in a food chain (concentrates toxins at higher trophic levels, where biomass is lower)
Greenhouse gases and climate change
caused by human activities is the rising concentration of atmospheric CO2 due to the burning of fossil fuels and deforestation
What is meant by the greenhouse effect? What would life on Earth be like without this effect?
The warming of Earth due to the atmospheric accumulation of carbon dioxide and certain other gases which absorb reflected infrared radiation and reradiate some of its back toward Earth. This effect is important for keeping Earth's surface at a habitable t
What is contributing to the great increase in atmospheric carbon dioxide? What are potential effects of this increase?
The thing contributing to the increase in CO2 is the burning of fossil fuel and human activity.
The effects of this increase is that the average global temperature will increase with increasing CO2. This warming would also then alter the geographic distri
growing enviromental problems
arise from growing amount of goods and resources that each of us consumes/consumption and the increasing human population (which has grown at an unpreccedented rate)
(ex: climate change)
human population growth since 1650
(increased relatively slowly until about 1650) at which time approximately 500 million people inhabited Earth. Our population doubled to 1 billion within the next two centuries, doubled again to 2 billion by 1930, and doubled still again by 1975 to more t
growth rates of nations
vary with their degree of industrialization, Most of the current global population growth is concentrated in developing countries/ less industralizied nations, Human population growth rates can be controlled through family planning, voluntary contraceptio
What is demographic transition? In demographic transition which falls first, birth or death rates?
the movement from high birth and death rates to low birth and death rates, death rates fall first
ecological footprint
concept summarizes the aggregate land and water area needed to sustain the people of a nation, to measure it add up all ecological productive land on the planet and divde by the population, combinantion of resource use per person and population densirt de
sustainable devleopment
is development that meets the needs of people today without limiting the ability of future generations to meet their needs