IB Environmental systems and societies: Unit 2 (2.1)

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Species

A group of organisms that can interbreed and produce fertile offspring, sharing common characteristics and genetic makeup.

Habitat

The natural environment where a species lives, including factors like food, water, and shelter that support its survival and reproduction. The environment in which a species normally lives.

Niche

The role or function of a species within its ecosystem, including its habitat, resource use, and interactions with other organisms. The particular set of abiotic and biotic conditions and resources to which an organism or population responds.

Fundamental Niche

The full range of environmental conditions and resources a species can potentially use without the influence of competition or other biotic factors.

Realized Niche

The actual conditions and resources a species use in the presence of competition and other biotic factors, reflecting its adaptations and interactions with other organisms.

Predation

The interaction where one organism, the predator, hunts and consumes another organism, the prey, affecting population dynamics within an ecosystem.

Herbivory

The consumption of plant material by animals, influencing plant populations and community structures in ecosystems.

Parasitism

A relationship where one organism, the parasite, lives on or in a host organism, obtaining nutrients at the host's expense, often harming the host.

Mutualism

A symbiotic relationship where both organisms benefit from the interaction, enhancing their survival and reproduction.

Disease

A harmful condition caused by pathogenic microorganisms that can affect the health of an organism, often leading to detrimental effects on its function and survival.

Competition

An interaction between organisms in which they vie for the same resources, such as food, space, or mates, often leading to a decrease in fitness for one or both parties involved.

Intraspecific competition

Competition among individuals of the same species for limited resources, which can affect population dynamics and individual fitness.

Interspecific competition

Competition between different species for shared resources, which can influence community structure and species diversity. Occurs when the niches of the organisms overlap.

Population

A group of individuals of the same species living in a specific area, interacting with one another and sharing resources.

Limiting factors

Environmental conditions that restrict population growth and distribution, such as availability of food, water, shelter, and space.

Carrying capacity

The maximum number of individuals of a species that an environment can sustainably support, determined by the availability of resources.

S-shaped curve —-lag phase

Population numbers are low leading to low birth rates

• Few individuals colonize the area, causing slow growth.

• Because numbers of individuals are low, birth rates are low.

S-shaped curve—Exponential growth phase

Population grows increasing fast. Limited factors are not restricting growth.

S-shaped curve—Transitional phase

Population growth slows down significantly but population still grows. Limited factors begin to affect a population.

S-shaped curve—Stationary phase

Population stabilizes. Limiting factors restrict to carrying capacity.

J population curve

Exponential growth (looks like a J) then crashes due to limiting factors. Organism that demonstrates this population growth produce many offspring with little parental care.