Flashcards in Chapter 9: Habitats Deck (41)
the total sum of all organisms in an area (genetic, species, and ecosystem diversity)
The number or variety of species in the world/particular region
What does the RICHNESS of a species describe?
The number of species
What is the evenness or relative abundance of a species?
The extent to which numbers of individuals of a different species are equal/unequal
What is genetic diversity?
The varieties in DNA among individuals within a species
What does genetic diversity mean for species survival?
More genetic diversity often ensures a better chance for a species to adapt to environmental change
What is a genetic bottleneck? When does it occur?
A genetic bottleneck is when a limited variety of genetic material is available to be passed down from the small amount of surviving species to their descendants. Occurs when there is a dramatic decrease in population.
What is ecosystem diversity based on?
Variations in a given area by climate, topography, soil type, other physical factors
The extinction of a species within a certain region
How do taxonomists(species scientists) name species?
Based on two parts: Genus(related) and Species(specific).
Ex. Polar bear- Ursus(genus) Maritimus(species)
American black bear- Ursus Americanus
What are generalists and specialists? In what environmental conditions are they preferred?
Generalist- species that can deal with a wide range of circumstances, do no one thing very well
Specialist- do only particular things very well
Generalists are preferred in variable environmental conditions, specialists preferred in stable conditions.
What is an ecotone?
Region where different types of habitats intermix
About how many species have been identified by scientists?
What is the latitudinal gradient?
The general increase of species richness as you get closer to the equator(due to plant productivity and climate stability)
What does SARA stand for
Canadian Species at Risk Act
What is a threatened species?
A species likely to become endangered in the near future
What is the background rate of extinction?
The rate at which many extinctions occured on earth prior to the appearance of humans (One by one)
When did the extinction of dinosaurs occur?
~65 million years ago, End of Cretaceous period
What makes a species "vulnerable"?
When their characteristics make them particularly sensitive to human activities or natural events
What does it mean for a species to be ENDEMIC?
Occurs in only one region in Earth(eg. golden toad of costa rica)
What are invasive species?
Non native species who are introduced to new environments(often pushes native species towards extinction)
Why are top predators often "keystone" species?
Top predators prey on many other carnivores, who pray on herbivores. The removal of a top predator could have a big impact on species lower down in the food chain
What is biophilia?
the connections that humans subconsciously seek with life(going to parks, owning pets etc.)
Nature Deficit Disorder
Alienation from the natural environment(can result in emotional and physical problems)
What is conservation biology?
A scientific discipline devoted to understanding the factors and processes that influence the loss, protection, and restoration of biological diversity
What is the equilibrium theory of island biogeography?
(mcarthur 1963) explains how species came to be distributed among oceanic islands, and habitat islands
Describe the distance effect?
The farther an island is located from a continent, the fewer species tend to find and colonize it.
Describe area effect?
Large islands tend to contain more species because they generally have more habitats than smaller islands. This provides suitable environments for a wider variety of species
What is habitat fragmentation?
When terrestrial habitat "islands" such as forests are cut into smaller areas by logging and road building