Unit 9 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 – – 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 –– Diversity in traits/genetic code within a group of

the same species

• Species Diversity – – Many different species within the same

community

• 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 – – 1 species extinction per 500 to 1,000 years

• Number of Mass Extinctions – – There have been 5 mass extinction events so far in

earth’s history– We are currently in the 6th mass extinction– A mass extinction is defined as an event causing the

death of more than half of the species on the planet

• Habitat Alteration – – The intentional or accidental destruction or change

in a habitat/niche– This is the leading cause of species extinction

• Invasive Species –

• Pollution –

• Population Growth –

• Overexploitation –

• Biophilia –

• Umbrella species –

• Endangered Species Act (1973)

• Captive Breeding – (zoos)– A strategy used to build up a declining population

& potentially reintroduce a threatened species into the wild.

– Very expensive & so far has only shown limited success (California condor)

• 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