Earth's Life Support Systems and Biodiversity

These flashcards cover key concepts related to Earth's life support systems, ecosystem dynamics, and biodiversity, focusing on definitions and important terms.

Lithosphere

The outer layer of the Earth, consisting of the crust and the upper mantle.

Hydrosphere

The combined mass of water found on, under, and above the surface of a planet.

Atmosphere

The layer of gases surrounding the Earth, primarily composed of nitrogen and oxygen.

Biosphere

The global sum of all ecosystems, representing the zone of life on Earth.

Ecosystem

A biological community of interacting organisms and their physical environment.

Ecology

The study of interactions among living organisms and their environment.

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem.

Genetic Diversity

The total number of genetic characteristics in the genetic makeup of a species.

Species Diversity

The variety of species within a given ecosystem, including both species richness and evenness.

Evolution

The process by which all forms of life have descended from common ancestors through changes over generations.

Mutations

Random changes in the DNA sequence that can lead to genetic diversity.

Natural Selection

The process through which traits that enhance survival and reproduction are passed on more frequently.

Artificial Selection

The intentional breeding of plants and animals by humans for desired traits.

Genetic Drift

Random fluctuations in the number of gene variants in a population.

Bottleneck Effect

A sharp reduction in the size of a population due to environmental events or human activities, resulting in a reduction in genetic diversity.

Founder Effect

A loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.

Speciation

The process through which new species arise from existing ones due to evolutionary processes.

Extinction

The end of a species, resulting when the last existing member dies out.

Population

A group of individuals of the same species living in the same area at the same time.

Population Size

The total number of individuals in a population.

Population Density

The number of individuals per unit area or volume.

Population Dispersion

The spatial arrangement of individuals within a population.

Population Distribution

The geographical area over which a species is found.

Demographics

The statistical characteristics of populations, such as birth rates, death rates, and age structure.

Population Dynamics

The study of how populations change in size, density, dispersion, and age structure over time.

Growth Models

Mathematical equations used to describe how populations grow under different conditions.

Exponential Growth

A growth pattern in which the population size increases at a constant rate per capita, resulting in a J-shaped curve when plotted against time.

Logistic Growth

A growth pattern in which the population's growth rate slows or stops following a period of exponential growth, as it approaches the carrying capacity, resulting in an S-shaped curve.

Growth Rate

The rate at which the number of individuals in a population increases or decreases over a given period.

Life Strategies

Adaptations in an organism's life cycle that influence its survival and reproduction, often categorized as r-selected or K-selected.

Biotic Potential

The maximum reproductive capacity of an organism under optimal environmental conditions.

Limiting Factors

Environmental conditions that restrict the growth, abundance, or distribution of an organism or a population.

Resource Limitation

The scarcity of resources (e.g., food, water, space) that restricts population growth and distribution.

Carrying Capacity

The maximum number of individuals of a species that an environment can sustainably support.

Density Independent Growth

Population growth that is not regulated by population density (e.g., natural disasters).

Density Dependent Growth

Population growth that is regulated by the density of the population (e.g., competition, predation, disease).

Community

An assemblage of different species living and interacting in the same area.

Species Interactions

The relationships between different species in a community, such as competition, predation, mutualism, commensalism, and parasitism.

Competition

An interaction between organisms or species in which both require a resource that is in limited supply.

Mutualism

A symbiotic relationship in which both organisms benefit.

Predation

A biological interaction where a predator feeds on its prey.

Herbivory

An interaction in which an herbivore feeds on plants or algae.

Commensalism

A symbiotic relationship in which one organism benefits and the other is neither harmed nor helped.

Resource Partitioning

The division of limited resources by species to help avoid interspecific competition in an ecological niche.

Keystone Species

A species whose impact on its community or ecosystem is disproportionately large relative to its abundance.

Invasive Species

A non-native species whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

Engineering Species

Organisms that create, significantly modify, maintain, or destroy a habitat.

Succession

The process of change in the species structure of an ecological community over time.

Primary Succession

The development of biological communities in an area where no soil exists.

Secondary Succession

The process of ecosystem development after a disturbance that leaves the soil intact.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Feeding Relationships

The interconnections between organisms based on who eats whom, illustrating the flow of energy in an ecosystem.

Trophic Levels

The position an organism occupies in a food chain, ranging from primary producers to top consumers.

Producers

Organisms that produce their own food, primarily through photosynthesis (autotrophs).

Consumers

Organisms that obtain energy by feeding on other organisms (heterotrophs).

Decomposers

Organisms that break down dead organic matter and waste products, recycling nutrients back into the ecosystem.

Energy Flow

The movement of energy through an ecosystem, typically from the sun to producers and then through various trophic levels.

Matter Cycling

The continuous movement of elements and compounds through ecosystems, often referred to as biogeochemical cycles.

Biogeochemical Cycles

Natural cycles that involve the movement of vital nutrients between the physical environment and living organisms.

Carbon Cycle

The biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.

Nitrogen Cycle

The biogeochemical process by which nitrogen is converted into various chemical forms as it circulates among the atmosphere, terrestrial, and marine ecosystems.

Phosphorus Cycle

The biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

Eutrophication

The excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.