exam 2
Exponential growth involves continuous change
dn/dt=rn
Doubling times and the rule of 70
a rule that can be used to determine how long it will take for a given population to double given its growth rate.
Exponential growth leads to crashes
A population can grow at an exponential rate very fast only if nothing limits its growth,
Logistic growth slows with population increase
growth rates slow down as the population approaches carrying capacity due to resources becoming scarce
How to predict sustainable yield
the carrying capacity divided by 2
Species respond to limits differently
r-selected species rely upon a high reproductive rate to overcome the high mortality of offspring with little or no parental care.
K-selected species have few offspring, slower growth as they near carrying capacity and exercise more parental care.
Survivorship curves show life histories
a graph of the number of individuals surviving at each age interval versus time
Intrinsic and extrinsic factors affect births and deaths
Intrinsic factors - operate within or between individual organisms in the same species.
Extrinsic factors - imposed from outside the population.
Interspecific interactions are between species
Organisms of two species use the same limited resource and have a negative impact on each other.
Stress and crowding can affect reproduction
their fertility rates decrease
Density-depend on effects can be dramatic
can influence a population including: disease, physiological stress and predation.
Genetic diversity may help a population survive
species to adapt to future environmental changes and avoid inbreedin
Evolution occurs through reproduction, variation, and natural selection
Evolution occurs through reproduction, variation, and natural selection
All species live within limits
All species live within limits
Resource partitioning can reduce competition
Resource partitioning can reduce competition
Community dynamics involves diversity, abundance, and distribution of species.
Community dynamics involves diversity, abundance, and distribution of species.
Biological communities vary in productivity
Biological communities vary in productivity
Biological communities may be adapted to disturbance
Biological communities may be adapted to disturbance
Community dynamics involves
diversity, abundance, and distribution of species
Ecological indicators
Complexity and connectedness.
Biological communities vary in productivity
Biological communities vary in productivity
Can development be sustainable?
economic growth, social inclusion and environmental protection.
Recourses, renewable or nonrenewable.
Recourses, renewable or nonrenewable.
Tropical moist forest
Humid regions in the tropics
Tropical seasonal forest
wet and dry seasons with hot temperatures year round
Tropical savannas and grasslands
Grasslands are lands with plants
Savannas are grasslands with scattered trees
Deserts
low moisture levels
Temperate grasslands
Communities of grasses and seasonal herbaceous flowering plants.
Temperate Shrubland
by warm, dry summers and cool, moist winters
Temperate Deciduous Forests . Coniferous Forest
Deciduous trees lose their leaves in winter as an adaptation to freezing temperatures.
Boreal forest
a conifer or conifer-hardwood forest type occurring on moist to dry sites characterized
Tundra
treeless landscape that occurs at high latitudes or on mountaintops.
What is biodiversity?
the variety and variability of life on Earth
Species are defined in different ways
Reproductive isolation, Phylogenetic species concept, Evolutionary species concept
Molecular techniques in taxonomy
•Genome - total D N A sequence that characterizes a species.
•Species classification or even identification of an individual can be done from samples such as blood, fur, or feces.