Ecology

Characteristics of K-selected organisms

- reproduce at a late age - slow maturation - much care for offspring

Human population size

7.5 billion people

Commensalism

an association between two organisms in which one benefits and the other derives neither benefit nor harm

Trophic chain

the food chain Tertiary consumers Secondary consumers Primary consumers Producers

species richness

the number of different species represented in an ecological community, landscape or region simply a count of species, and it does not take into account the abundances of the species or their relative abundance distributions

Characteristics of r-selected organisms

- reproduce at an early age - fast maturation - little care for offspring

Community

an interacting group of various species in a common location

mutualism

the way two organisms of different species exist in a relationship in which each individual benefits from the activity of the other

how does biological magnification occurs

- the increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain - the buildup of certain substances, such as DDT, in the bodies of organisms at higher trophic levels of food webs. DDT was once used extensively as an insecticide. DDT builds up in the fatty tissues of organisms

What factors affect population size?

1) amount of food 2) amount of shelter 3) amount of access of medication and/or medical care 4) birth rate increase or decrease 5) death rate increase or decrease 6) amount of water

How much energy transferred between trophic levels?

10%

What is a keystone species and how does it affects communities

A species whose presence and role within an ecosystem has a disproportionate effect on other organisms within the system. A keystone species is often a dominant predator whose removal allows a prey population to explode and often decreases overall diversity.

Ecosystem

A system that includes all living organisms (biotic factors) in an area as well as its physical environment (abiotic factors) functioning together as a unit

What is eutrophication?

In aquatic environment Nitrogen and Phosphorus and Oxygen is limited. This amount of oxygen limits the amount of growth. The increase of Nitrogen and Phosphorus causes the bottom of the food chain to explode in population. This is not good because they end up using up all of the oxygen. In addition to this because there is so much algae growth there is an increase in bacteria decomposers which also use up oxygen.

niche/resource partitioning

Resource partitioning in three species of birds, all of which feed on insects in the same types of pine tree

logistic model of population growth

When resources are limited, populations exhibit logistic growth

exponential model of population growth

When resources are unlimited, populations exhibit exponential growth, resulting in a J-shaped curve

predation

a biological interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked)

relative abundance

a component of biodiversity and refers to how common or rare a species is relative to other species in a defined location or community

Survivorship curve

a graph showing the number or proportion of individuals surviving to each age for a given species or group Type I: over Type II: straight down Type III: under

Understand the ecological pyramid

a graphical representation designed to show the biomass or bio productivity at each trophic level in a given ecosystem

Population

all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding

competition

an interaction between organisms or species in which both the organisms or species are harmed

density-dependent factors

factors whose effects on the size or growth of the population vary with the population density. There are many types of density dependent limiting factors such as; availability of food, predation, disease, and migration. However the main factor is the availability of food.

density-independent factors

factors, such as weather and climate, exert their influences on population size regardless of the population's density. In contrast, the effects of density-dependent factors intensify as the population increases in size.

What is primary productivity and how does it affect an ecosystem?

gross primary productivity minus the rate of energy loss to metabolism and maintenance. In other words, it's the rate at which energy is stored as biomass by plants or other primary producers and made available to the consumers in the ecosystem

Random dispersion

individuals are arranged without any apparent pattern

Uniform dispersion

individuals are spaced evenly throughout an area

parasitism

relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing the host organism

Trophic web

represents feeding relationships within a community

Competitive Exclusion Principle

sometimes referred to as Gause's law, is a proposition named for Georgy Gause that two species competing for the same limiting resource cannot coexist at constant population values

Semelparity

species is characterized by a single reproductive episode before death

Iteroparity

species is characterized by multiple reproductive cycles over the course of its lifetime

herbivory

the consumption of plant material by animals

niche

the fit of a species living under specific environmental conditions describes how an organism or population responds to the distribution of resources and competitors (for example, by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (for example, limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey)

Species diversity

the number of different species that are represented in a given community

carrying capacity

the number of people, other living organisms, or crops that a region can support without environmental degradation

character displacement

the phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur, but are minimized or lost where the species' distributions do not overlap

Trophic levels

the position it occupies in a food chain

What is coevolution?

used to describe cases where two (or more) species reciprocally affect each other's evolution

Clumped dispersion

when individuals in a population are clustered together, creating some patches with many individuals and some patches with no individuals