Biology Lecture 2 Ecology Flashcards
define population
all the individuals of a given species that live and reproduce in a particular time and place
define community (4)
local populations of multiple species that may interact with one another
why is there a spatial distribution of some species
different feeding areas and breeding areas
what are the two types of distribution of species (4) (4)
spatial and temporal
explain the temporal distribution of species
different times
niche definition
the ways an organism uses the resources of its environment
explain the competitive exclusion principle
complete competitors occupying identical niches cannot coexist
define the fundamental niche (4)
habitat that a species is capable of using, based on physiological needs
define the realised niche (4)
actual conditions under which species is found, incorporates ecological factors, such as competition.
define a keystone species (4)
a species that has a disproportionately large impact on the community
trophic cascade definition (4)
processes at an upper trophic level flow down to two or more lower levels
explain top-down control
this is very relevant, e.g., keystone species removed from both terrestrial and aquatic ecosystems
explain bottom-up control
changes to primary producers affect higher trophic levels
what are the key elements of the environment
temperature water sunlight soil
what determins which organisms live in a particular climate or region (4) (4)
nature of the physical environment largely determines this
temperature
most organisms are adapted to live within a relatively narrow range of temperatures and wil not thrive if temperatures are colder or warmer, e.g. growing seasons of plants is affected by temperature
water
all organisms require water. on land, water is often scarce, so patterns of rainfall have a major influence on life
sunlight
almost all ecosystems rely on energy captured by photosynthesis. the availability of light influences the amount of life an ecosystem can support, particularly below the surface in marine communities
soil
the physical consistency, pH, and mineral composition of the soil often severely limit terrestrial plant growth, particularly the availability of nitrogen and phosphorus
how can responses to environmental variation be seen in the short-term
organisms have variety of ways of coping with environmental change
how can responses to environmental variation be seen in the long-term
natural selection can operate to make a population better adapted to its environment
why do organisms have homeostatial abilities (4)
they’re a product of natural selection acting in a particular environment setting over time, which explains why an individual organism that is moved to a different environment may not survive.
what is a norm of reaction
the ability to produce multiple phenotypes from a single genotype
If such flexibility is useful, why aren’t all traits so plastic?
The presumed answer is that such flexibility has a cost such that individuals that are genetically programmed to produce only a single phenotype have an advantage that offsets the advantages of a large norm of reaction.
The existence of norms of reaction has
several important consequences. Such flexibility is obviously useful to a species that may find itself in different environments, particularly
sedentary species that cannot just get up and move. However, it is important to remember that such differences in phenotype among
individuals do not reflect genetic differences-rather, individuals may be genetically identical, but still have grown up in different
environments. Of course, a further consequence of this is that such nongenetic differences are not transmitted to the next generation
because they are not genetically inherited.
example of a behavioral adaptation
Many animals deal with variation in the environment by moving from one patch of habitat to another, avoiding areas that are unsuitable.
The ability of an individual to alter its physiology, morphology, or behavior is itself an evolutionary adaptation, the result of natural
selection. The results of natural selection can also be detected by comparing populations of the same species that live in different
environments.
Lizards that live in different climates exhibit physiological adaptations for coping with life at different temperatures. Desert
lizards are unaffected by high temperatures that would kill a lizard from northern Europe, but the northern lizards are capable of running,
capturing prey, and digesting food at cooler temperatures at which desert lizards would be completely immobilized.
types of interaction
mutualism
parasitism
