Response To Environment, Energy Flow, & Population Ecology
Define heterotrophs
Organisms that cannot make their own food and hence must consume food
If ample nutrients are available and there are no natural predators in the habitat, the population should undergo what form of growth?
exponential growth
The definition of a population vs. the definition of a community
Population is a single species, community is all living components of the ecosystem.
Describe the impact of deforestation on biodiversity
Deforestation removes the natural habitat of many species. Particularly in tropical rain forests which are biodiversity hot spots, this reduces the biodiversity of the Earth.
True or False: Mutations are directed by environmental pressures
False. Selection is directed by specific environmental pressures. Mutations are considered to be random.
Population growth rate, in terms of birth rate and death rate?
Population growth rate = birth rate - death rate
How much of the energy from one trophic level makes it to the next highest trophic level and why?
10%. The remaining energy is said to be lost as heat. There is energy inefficiency in consuming organisms higher up on the trophic pyramid.
What critical aspect of a keystone species makes a particular species a keystone species?
The ecosystem is significantly disrupted if there is a disruption to the population of a keystone species. Note that this definition does not limit an ecosystem to a single keystone species.
What, meteorologically, does El Nino refer to and what is one potential impact on living populations of organisms?
wind pattern that creates warming of surface waters in the eastern tropical Pacific ocean in late December, creating climatic changes in this region and elsewhere.
This can impact overall temperatures, precipitation, and other environmental variables that influence living components of ecosystems in distant locations such as the US.
True. There has not been sufficient time for evolution to take place around the presence of the invasive species upon its initial introduction to the new location.
The smaller the organism, what is true of the metabolic rate per gram of body tissue
higher metabolic rate, all else equal
Why is Rmax different in bacteria than in leopards?
Shorter reproduction cycle in bacteria than in leopards
Describe the fluctuations over time in a population of predators and a corresponding population of their prey
There is a negative feedback component to the relationship, in that the higher the population of predators vs. prey, the less food is available the the predator population drops. The more prey vs. predators, the more likely each predator is to be able to feed itself and reproduce, hence the predator population increases.
Provide an example of how continental drift impacts living populations of organisms
convection currents altered, opportunities for geographically driven independent evolution from common ancestral species, shifting ice caps, etc.
The invasive species will expand its habitat into the surrounding bodies of water, since it is unlikely that those nearby bodies of water contain any natural predators for it either (given that they reside in the same global hemisphere).
Red deer males exchange signals that suggest fighting ability, such as roaring. These signals in many cases eliminate an actual fight from occurring, as both parties accept the outcome of the roaring comparison. What is the evolutionary advantage of such behavior?
Fewer actual physical conflicts is better for the survival of more members of the population (and hence helps to preserve the biodiversity of the population).
What occurs within the logistic growth equation as the population size approaches carrying capacity?
The (K-N / K) term gets smaller, making the dN / dt incrementally smaller, hence the bending of the corresponding curve.
Describe how a single lake can be an example of niche partitioning
Different areas of the lake, different depths of the lake, different temperature zones of the lake, different prey species in the same areas of the lake, etc.
Describe the impact of the removal of wolves from Yellowstone National Park
65 million years ago a meteor impacted the Yucatan Peninsula. It is the central component for a hypothesis about the extinction of the dinosaurs. How were other species impacted by the meteor?
An "airborne curtain" of sulfate molecules blocked out much of the sunlight from getting to Earth's surface. This resulted in the extinction of many plant species, and therefore the extinction of many herbivores, and therefore the extinction of many carnivores. In short, it was a period of mass extinction.
Vervet monkeys produce a cough call when airborne predators (such as eagles) approach. Describe the evolutionary significance of this behavior?
warns the other members of the population about the predator so the population can seek appropriate cover in the vegetation and avoid predation
What could be said in terms of Simpson's Diversity Index, of a community with 10 species with 10 members of each population, as compared to a community with 10 species in which half of the species have 15 members of each population and the other half of the species have 5 members in each population?
The first population has a higher Simpson's Diversity index (0.9 vs. 0.875)
Describe how the reintroduction of Wolves to Yellowstone National Park was an example of a trophic cascade
By controlling the elk population (the intermediate species here), the wolves indirectly promoted the population sizes of the species at lower trophic levels consumed by the elk
In order to produce 1 kg of edible meat, multiple kilograms of grains and grasses (producer species) must be used. What is the impact of this knowledge on the global population maximum for human beings?
The more meat people consume, the fewer people the Earth can support. It is estimated that if everyone ate as much meat as Americans, the Earth could support circa 4 billion people only.
There is a natural marine biodiversity gradient according to latitude as follows: biodiversity of marine species is greatest close to the equator, and lessens as one gets farther in latitude from the equator. Predict the impact of global warming on this natural gradient.
Some species are moving farther away from the equator in order to locate their homeostatic water temperature. This is reducing species diversity at the equator relative to areas of a mid-range distance from the equator.