Species Interactions, Ecological succession, and Population Control

Interspecific competition.

Attempts by members of two or more species to use the same limited resources in an ecosystem.

Examples: Humans and animals

Intraspecific competition

Intraspecific competition takes places within a species

Resource partitioning

Explain how it can increase species diversity?

Process of dividing up resources in and ecosystem so that species with similar needs (overlapping ecological niches) use the same scarce resources at different times, in different ways, or in different places.

Example: Insect-eating bird species

It increases species diversity, because eventually they can't all survive by sharing the same exact resource so one has to evolve with either having less or none of the resource

Predation

Interaction in which an organism of one species (the predator) captures and feeds on some or all parts of an organism of another species (the prey)

Predator species

Organism that captures and feeds on some or all parts of an organism of another species (the prey)

Example: Lion

Prey species

Organism that is killed by an organism of another species (the predator) and serves as its source of food.

Example: Zebra

Predator-prey relationship

Why is it important?

Relationship that has evolved between two organisms, in which one organism has become the prey for the other, the latter called the predator.

It is important because interactions between predator and prey species can drive each other's evolution.

Describe three ways in which predators can increase their chances of feeding on their prey and three ways in which prey species can avoid their predators.

Camouflage, Chemical Warfare, Ability to fly and run faster than their prey.

Camouflage, Chemical Warfare, Warning Coloration, Behavioral Strategies.

Parasitism

Interaction between species in which one organism, called the parasite, preys on another organism, called the host, by living on or in the host.

Example: fleas/ticks/tapeworms and mammals or mosquitoes and humans

Mutualism

Type of species interaction in which both participating species generally benefit

Example: bacteria in human intestines or Oxpeckers and Impalas

Commensalism

An interaction between organisms of different species in which one type of organism benefits and the other type is neither helped nor harmed to any great degree

Example: Epiphytes and tree trunks/ branches or bees and pollen

Ecological succession

Process in which communities of plant and animal species in a particular area are replaced over time by a series of different and often more complex communities.

Primary ecological succession

Ecological succession in an area without soil of bottom sediments

Examples: bare rock exposed by a retreating glacier, newly cooled lava, an abandoned highway or parking lot, and a newly created shallow pond or reservoir

Secondary ecological succession

Ecological succession in an area in which natural vegetation has been removed or destroyed but the soil or bottom sediment has not been destroyed.

Examples: abandoned farmland, burned or cut forests, heavily polluted streams, and flooded land

Inertia (persistence)

The ability of living system such as a grassland or a forest to survive moderate disturbances

Example: Tropical Rain Forests

Resilience

The ability of a living system to be restored through secondary succession after a more severe disturbance

Example: Grasslands

Population

Group of individual organisms of the same species living in a particular area.

Why do most populations live in clumps?

Allows them to cluster where resources are available, provides some protection from predators, and gives predator species a better chance of getting a meal.

Four variables that govern changes in population size.

Births, deaths, immigration, and emigration

Limiting Factor

Single factor that limits the growth, abundance, or distribution of the population of a species in an ecosystem.

Example: low precipitation levels in desert ecosystems limit desert plant growth.

Exponential growth of a population

Growth in which some quantity, such as population size or economic output, increases at a constant rate per unit of time. J-curve

Logistic growth of a population

Pattern in which exponential population growth occurs when the population is small, and population growth decreases steadily with time as the population approaches the carrying capacity. S-curve

Environmental Resistance

All of the limiting factors that act together to limit the growth of a population.

Carrying capacity of an environment

Maximum population of a particular species that a given habitat can support over a given period.

Population Crash

Dieback of a population that has depleted its supply of resources, exceeding the carrying capacity of its environment.

Example: Reindeer were introduced onto a small island in the Bering Sea in the early 1900s

R-selected species

Species that have a capacity for a high rate of population growth. They tend to have many, usually small, offspring and to give them little or no parental care of protection.

Examples: algae, bacteria, and most insects

K-selected species

These species tend to do well in competitive conditions when their population size is near the carrying capacity of their environment. They tend to reproduce later in life and have a small number of offspring with fairly long life spans.

Example: Most large mammals, birds of prey,, and large and long-lived plants