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Unit 11 Exam Review. Conservation Biology – Conservation may be defined as the management and sustainable use of the natural environment and natural resources for ethical reasons and the benefit of humanity. Human history & habitat destruction –
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Conservation Biology – • Conservation may be defined as the management and sustainable use of the natural environment and natural resources for ethical reasons and the benefit of humanity. • Human history & habitat destruction – • Unsustainable land use practices have been around for thousands of years.
Preservationists – • Conservationists –
Three Guiding Principles of Conservation Biology: • Evolutionary Change – • Consequently the goal of this principle is to allow populations to change in response to environmental changes through adaptations. • Dynamic Ecology – • The ecological world is seen as dynamic; largely functioning through non-equilibrium principles. • Human Change – • Humans are participants within both na-tural and perturbed ecosystems and their presence within ecosystems needs to be recognized and accounted for.
Conservation Biology & Economics – • Three objectives of the World Conservation Strategy – • The maintenance of the ecological processes that life depends on; • The sustainable use of ecosystems and their component species; • The conservation of genetic diversity.
Conservation Biology, Standards of Living, and Human population – • Human expectations of a decent standard of living include food, shelter, water, space, education and a freedom of choice. • The problem of human pressure on natural resources is further complicated by the global problem of population growth.
Conservation & Self-Sufficiency – • Many countries that, a few years ago, were self-sufficient in food, now have to import food. • They tend to make extensive rather than intensive use of the land. • Landless people migrate to unoccupied public lands (i.e. natural vegetation). • Government indifference (as shown by their priorities) is one of the main causes of hunger.
Unnecessary Wastefulness & its Consequences – • Wastefulness is not the confined to the poor. Wealthy societies are even more wasteful. • In many developing countries, large tracts of land are wastefully cleared to provide exports to these wealthy countries. • The fishing industries of the wealthy nations have collapsed. The fishing industries of de-veloping countries have also collapsed due to local exploitation for export to the wealthy nations or their inability to police fishing rights leased to wealthy countries. • Overexploitation can become habitat destruction and cause species extinction. • The loss of tropical rainforests is serious. Other ecosystems under threat are wetlands, coastal areas, arid and semi-arid rangelands.
Genetic Diversity – • Species Diversity –
Ecosystem Diversity – • Approximate number of known species on the planet – • Reasons for the above-mentioned uncertainty:
Adaptive radiation – • Latitudinal Gradient – • Extinction vs. Extirpation –
Background Extinction – • Number of Mass Extinctions – • Habitat Alteration –
Invasive Species – • Pollution – • Population Growth –
Overexploitation – • Biophilia – • Umbrella species –
Endangered Species Act (1973) • Captive Breeding –
Biodiversity Hotspot – • IUCN – • Extinct – • Extinct in the Wild –
Critically endangered – • Endangered – • Vulnerable –
Conservation Dependent – • Near Threatened – • Least Concerned –
Four Factors creating the Basis for the Concern over Extinction – • The unprecedented level of threats to biodiversity; • The escalation of the threats to biodiversity; • The observation that the threats to biodiversity are synergistic; • The realization that what harms biodiversity will harm humanity.
Population & Size & Survival – • Births and immigrations add to the population size while deaths and emigrations reduce the population size. • Population size and survival depend on: • The availability of resources • The amount of suitable habitat • Predation/parasitism • Disease • Social interactions
Mechanisms of Extinction in Single Populations – • Demographic uncertainty • Environmental uncertainty • ‘Natural’ catastrophes • Loss of genetic diversity • Mechanisms may interact, compounding the effect on the population. • Population size is critical to survival.
Minimum Viable Population – • the lowest number of individuals needed to ensure that a population has a selected probability of survival for a set time period without significant loss of evolutionary adaptability. • No MVP is applicable to all species.
Vulnerability to Extinction – • Species that only occur in threatened habitat types • Species that are economically valuable to humans • Species that do not have any/much experience of disturbance • Species requiring large home ranges