Chapter 8 Flashcards
Biodiversity
the variety of life across all levels of biological organization and includes diversity in species, genes, populations, communities and ecosystems
Species Diversity
the number or variety of species found in a particular region; one component is species richness and relative abundance/evenness
Genetic Diversity
the differences in DNA composition among individuals and provides the raw material for adaptation to local conditions
Ecosystem Diversity
the number and variety of ecosystems; above species diversity
Quantifying Diversity
Simpson’s Diversity Index is a measure of diversity. In ecology, it is often used to quantify the biodiversity of a habitat. It takes into account the number of species present, as well as the abundance of each species.
Species Richness
the number of species
Species Evenness
AKA relative abundance; the degree to which species differ in numbers of individuals (greater evenness means they differ less)
Distribution of Biodiversity
unevenly distributed; higher near the equator b/c there are larger number of organisms due to greater amt of solar energy so more productivity, relatively stable climates
Some groups contain more species than others (fig. 8.3)
most species are animals, then 3/4 of animals are insects; among vertebrates only 9% are mammels
Potential Bias in Species Estimates
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Relationship between latitude and species diversity
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Food security
Throughout history humans used 7000 plant species and several thousand animal species; now we get 90% of our food from just 15 crops & 8 livestock species and this lack of diversity leaves us vulnerable to crop failures; biodiversity enhances food security; need to harvest wild species and rare crop varieties
Medicine
organisms provide drugs and medicine; many of today’s pharmaceuticals are derived from chemical compounds from wild plants
Ecosystem Services
forests provide clean air and water, buffer hydrologic systems against flooding and drought, timber; native crops provide insurance from drought and disease; wildlife attracts tourism that boosts economies; these are all free of charge but that makes them vulnerable to tragedy of the commons (more on pg 167)
Ecosystem Function
biodiversity enhances the stability of communities and ecosystems, as well as increase the resilience of ecological systems-their ability to withstand disturbance, recover from stress or adapt to change; loss of biodiversity can diminish a natural system’s ability to function and provide services
Tourism and Recreation
people travel to observe wildlife and natural areas they create economic opportunities for area residents; ecotourism
Biophilia
human beings share an instinctive love for nature and feel an emotional bond with other living things; E.O. Wilson; love for pets, affinity for parks and wildlife, high value of real estate with views of natural landscapes; hiking, bird-watching, fishing, hunting, backpacking, etc
Nature Deficit Disorder
children are increasingly deprived of outdoor experiences and direct contact with wild organisms; Richard Louv argues that alienation from biodiversity damages childhood development and may develop emotional and psychological challenges as they get older
Extinction
occurs when the last member of a species dies and the species ceases to exist
Extirpation
AKA local extinction; the disappearance of a population from an area but not the entire species globally
Background Rate of Extinction
most extinctions occurs gradually, one species at a time
Mass Extinction events
in the past 440 million years our planet experienced five major mass extinctions (Table 8.3)
Humanity and the 6th Mass Extinction
if current trends continue, the modern era (AKA the Quaternary period) may see the extinction of more than half of all known species; we are causing it and we will suffer as a result
Living Planet Index
this index expresses how large the average population size of a species is now, relative to its size in the baseline year of 1970; used to quantify and summarize changes globally; summarizes trends
