Module 6 - Ecology Flashcards
The definition of Ecology
the interactions of any organism with its environment, both the living (biotic) and non-living (abiotic) portions.
ecosystem
consists of all the living and nonliving components of a defined geographical area
A population consists of
all the members of a particular species that live within an ecosystem
a community is defined as a
group of interacting species populations occupying the same geographical area.
Environmental resistance is the
push back of the environment on the population and take the form of competition, predation, as well as natural events.
logistic growth curve is what shape?
S shaped curve
The concept of an ecological carrying capacity is that
The maximum population size that can be sustained indefinitely without damage to an ecosystem is called the ecosystem’s carrying capacity
biosphere
All of the ecosystems in the entire habitable surface of Earth comprise the biosphere
can natural increase of a population be negative?
yes if deaths exceed births.
Regardless of the population density, population size is limited by ____-____ ____.
Density-independent factors
Density-dependent factors
increase in effectiveness as the population density increases
some density independent factors
weather (short-term atmospheric conditions such as temperature, rainfall, and wind) and climate (long-term weather patterns).
interspecific competition
two or more species utilize the same resources
In consumer–prey interactions
one species (the consumer) uses another species (the prey) as a food source.
In mutualism
two species cooperate in ways that increase both species’ access to resources.
In symbiosis
the relationships are prolonged and intimate, so that members of the two species are almost always found together.
co-evolution
inter-acting species acting as agents of evolution for one of the species. for example a fox making a rabbit able to run faster over generations.
Ecological niche
is a term for the position of a species within an ecosystem, describing both the range of conditions necessary for persistence of the species, and its ecological role in the ecosystem.
resource partitioning helps to reduce…
interspecific competition as different species adapt to feeding on different parts of a plant.
intraspecific competition
is the most intense form of competition, because every member of the species competes for all of the same resources.
In an ecosystem, each category of organisms through which energy passes is called a
trophic level, photosynthetic organisms make up the first trophic level.
autotrophs
produce their own energy using inorganic nutrients and solar energy.
heterotroph or consumer
organism which cannot produce its own energy from the sun.
primary consumers (herbivores)
feed directly on producers (plant matter)
Secondary consumers
consume herbivores, do not consume carnivores.
Tertiary consumers.
when an organism consumes other carnivores it occupys the third trophic level.
usually given as grams of biomass per square meter per year is
___ _____ _____
net primary
production.
A food chain is a
linear feeding relationship that includes a single species in each trophic level that is fed upon by a single species in the trophic level just above it.
microscopic photosynthetic protists and bacteria collectively called
phytoplankton.
what shows many interconnected food chains and more accurately describes the actual feeding relationships in a community ?
A food web
Detritivores (“debris- eaters”)
are an army of mostly small and often unnoticed organisms, including nematode worms, earthworms, milli- pedes, dung beetles, and the larvae of some flies. feed on chunks of organic matter.
Decomposers
are primarily fungi and bacteria.
Biomagnification
the increasing accumulation of a toxic substance in progressively higher trophic levels. For instance, accumulation of toxic chemicals in shark meat
An energy pyramid illustrates
the energy relationships between trophic levels widest at the base and progressively narrowing in higher trophic levels
The four postulates regarding populations proposed by Darwin and Wallace’s theory of evolution by natural selection
- individuals in a population Vary
- Traits are passed from parent to offspring
- some individuals Fail to survive and reproduce
- Survival and reproduction are not Determined by chance but by characteristics
evolution
change over time in the characteristics of a population.
process of natural selection
Individuals with advantageous traits survive longest and leave the most offspring with those similar traits
Vestigial structures
a structure that is an evolutionary remnant that performed a useful function in an ancestor, but is no longer useful. Like a tail bone in a human.
Convergent evolution:
the independent evolution of similar structures amongst unrelated organisms as a result of similar environmental pressures. Like a bird and bat wings.
Analogous features:
structures that have a similar function and a superficially similar appearance but very different anatomies. For instance, wings of birds and insects
Artificial selection:
the purposeful breeding of domesticated animals and plants to produced desired characteristics
Gene pool:
the total of all alleles, of all genes in a population
Gene flow:
the movement of alleles from one population to another owing to the movement of individual organisms
Allele frequency:
for any given gene, the relative proportion of each allele of that gene in a population. For instance, for the eye color allele, the proportion in the population that holds the blue allele, compared to all other colors
Genetic drift:
a change in the allele frequencies of a small population purely by chance
Population bottleneck:
the result of an event that causes a population to become extremely small; this may cause genetic drift that results in changed allele frequencies and loss of genetic variability
Founder effect:
an isolated population is founded by a small number of individuals. This may result in genetic drift if allele frequencies in the founder population are different from those of the parent population
Adaptation:
a trait that increases the ability of an individual to survive and reproduce compared to individuals without the trait
