Ecological Succession, Relationships, and Biomes: A Comprehensive Biology Review

Ecological Succession

Series of changes that occur in an ecological community after a disturbance.

Primary Succession

Occurs on sites that lack living organisms and where no soil is initially present.

Pioneer Species

Species that colonize an uninhabited area and begin the ecological cycle so other species can inhabit the area.

Lichens and Moss

Pioneer species since they grow on bare rock and produce the soil that allows other life to begin.

Secondary Succession

Occurs on sites where some organisms have survived the disturbance and where soil is present.

Climax Community

The stable, fully grown state of a community at the end of ecological succession.

Autotrophs

Organisms that produce their own food, such as plants, algae, trees, grasses, plankton, flowers, and seaweed.

Heterotrophs

Organisms that cannot produce their own food and rely on consuming other organisms.

Primary Producers

Autotrophs that are the first level in the energy pyramid.

Primary Consumers

Herbivores that consume primary producers.

Secondary Consumers

Carnivores that consume primary consumers.

Tertiary Consumers

Top carnivores that eat meat and are not naturally hunted/eaten by anything else in the wild.

Omnivores

Organisms that eat both plants and animals.

Detrivores

Organisms that eat organic waste and dead bodies.

Decomposers

Heterotrophs that break down organic material and cause decay, returning nutrients to the soil/water.

Energy Flow in Ecosystems

The flow of energy through ecosystems is linear because energy cannot be reused by organisms.

Photosynthesis Equation

H2O + CO2 + (light) energy → O2 + C6H12O6.

Energy Transfer Efficiency

Each trophic level receives only 10% of the energy from the previous level.

Energy Loss

90% of the energy is lost as heat during energy transfer between trophic levels.

Energy Pyramid

A diagram that shows decreasing energy flow through the four trophic levels.

Trophic Levels

1st level = autotrophs, 2nd level = primary consumers, 3rd level = secondary consumers, 4th level = tertiary consumers.

Tertiary Consumers / Top Carnivores

Ex: lion, hawk, wolf, shark, orca

Secondary Consumers / Carnivores

Ex: spider, snake, trout, frog, seal

Primary Consumers / Herbivores

Ex: rabbit, deer, mouse, grasshopper, koala

Autotrophs / Primary Producers

Ex: plants, algae, trees, grasses, plankton, flowers, seaweed

Energy Flow

Describes who eats whom in an ecosystem

Food Chain

Describes the sequential passage of energy, must start with a producer and shows who eats whom

Food Web

Shows the complexity of the interconnected food chains, several food chains woven together, and shows how every organism is interdependent

Biomass

The combined weight of all the organisms in a trophic level

Predation

The act of killing and eating another organism

Coevolution

When two species influence each other's evolution

Keystone Species

Plays a major role in a community and affects many other species; removal of this species greatly impacts the community

Indigenous Species

Growing and existing naturally in a region; a native

Exotic Species

A non-native organism deliberately or accidentally introduced into a new habitat

Biological Magnification

Process in which pollutants become more concentrated in successive trophic levels

Pollutants in Biological Magnification

Often harms the organisms in which these materials concentrate, since the pollutants are often toxic

Impact of Exotic Species

Can have many negative impacts on the environment, the economy, and human health

Effects of Pollutants

Pollutants that magnify tend to be taken up by producers at a higher than normal rate

Storage of Pollutants

The pollutants are absorbed and stored in the bodies of consumers (usually in the fat)

Example of Exotic Species Impact

Approximately 68% of fish species lost in North America over the last century were caused by an invasion of exotic species

Biomagnification

The process by which pollutants build up in the fatty tissues of consumers.

DDT

A pesticide used for a long time to kill disease-causing insects, which does no real damage to some organisms, including humans, but is deadly or has long-term effects on other species.

Population

A group of individuals of the same species living in a specific area.

Population Growth Factors

Three factors that control population growth: Births, Deaths, and Migration.

Immigration

The movement of individuals into a population.

Emigration

The movement of individuals out of a population.

Limiting Factor

Any factor that restrains the growth of a population, such as disease, parasites, predators, or availability of resources.

Density-independent Factors

Limiting factors that affect a population's growth regardless of its size, such as natural events and human activities.

Density-dependent Factors

Limiting factors whose impact on a population's growth is affected by the population size.

Growth Rate

The rate at which a population increases or decreases, indicated by the difference between birth rate and death rate.

Exponential Growth

A growth pattern where births consistently exceed deaths, creating a 'J-shaped' curve on a graph.

Logistic Growth

A growth pattern where populations show an 'S-shaped' curve as they reach carrying capacity.

Carrying Capacity

The maximum number of organisms a given area can support.

Nutrient Flow

The flow of inorganic nutrients through an ecosystem, which are recycled.

Reservoir

A storage site for nutrients in biogeochemical cycles.

Water Cycle

The cycle that includes evaporation, transpiration, and precipitation, with gravity playing a key role.

Transpiration

The process by which water vapor is released from plants, chiefly at the leaves via their stomata.

Carbon Cycle

The cycle that involves photosynthesis and respiration as the basis for carbon movement in ecosystems.

Photosynthesis

Plants take in CO2 & give off O2.

Respiration

Use O2 & give off CO2.

Fossil Fuels

Remains of organisms transformed by decay, heat, and pressure into energy-rich molecules (Ex: coal, oil, natural gas).

Nitrogen Cycle

N2 must be converted to a usable form for organisms through nitrogen fixation.

Nitrogen Fixation

Process where nitrogen gets 'fixed' by bacteria into forms usable by organisms = nitrate (NO3) or ammonia (NH4).

Nitrate

Form of nitrogen that most plants can take up and convert to amino acids.

Amino Acids

Acquired by animals when they eat plants or other animals.

Ammonia

Returned to the soil or water when organisms die or release waste, usually from decomposers.

Nitrite

Less toxic form of nitrogen that bacteria convert ammonia into.

Denitrifying Bacteria

Convert nitrate back into nitrogen gas (N2), which returns to the air.

Phosphorus Cycle

Phosphate is never a part of the atmosphere; it will always be in one of three forms: part of an organism, dissolved in water or soil, or in the form of rock.

Habitat Destruction

Ex: 98% of all tropical rain forests have been destroyed.

Ozone Layer

Protects Earth from harmful UV rays; its breakdown increases skin cancer occurrence and damages plant photosynthesis.

Greenhouse Gases

Examples include methane, CFCs, & CO2; they trap heat from the sun.

Global Warming Effects

Negative effects include changing temperature and precipitation patterns, increases in ocean temperatures, sea level, and acidity.

Acid Rain

Has a pH of 4.0-4.5 (Normal=5.5).

Biodiversity

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

Endangered species

Species that are in danger of going extinct.

Rate of extinction

Currently at an all-time high, with estimates of 50-150 species becoming extinct each day.

Reasons for extinction

Factors contributing to extinction include climate change, toxins in the environment, habitat destruction, and introduced species.

Balanced ecosystems

Ecosystems that maintain stability and health, which can be disrupted by the extinction of species.

Medicinal use of species

The potential for discovering medicines and other products from various species.

Biomes

Large terrestrial regions characterized by similar climate, soil, and living things.

Tundra

Cold, boggy plains characterized by permafrost, located far north or at high altitudes.

Taiga / Boreal Forest

Cool weather, evergreen forests of northern areas, primarily consisting of conifer trees.

Deciduous Forests

Forests with a dense canopy of mostly deciduous trees that lose their leaves in fall/winter.

Temperate Grasslands

Grass-dominated areas found in temperate regions, characterized by nutrient-rich soil and few trees.

Savannas

Tropical grasslands with scattered trees, experiencing seasonal rainfall and drought.

Chaparral

A temperate biome with hot, dry summers and mild winters, often adapted to fire.

Deserts

Arid ecosystems defined by a lack of rainfall, with extreme temperature changes and specially adapted organisms.

Tropical rain forests

Lush ecosystems located along the equator, known for their high biodiversity and year-round rainfall.

Permafrost

Ground that never completely thaws, characteristic of tundra biomes.

Conifers

Evergreen trees that produce cones and have needles instead of leaves, typical in taiga forests.

Nutrient-rich soil

Soil that is fertile and well-suited for agriculture, often found in temperate grasslands.

Adaptations to dry conditions

Special root systems and hard leaves in plants that help them survive in chaparral and desert biomes.

Extreme temperature changes

The significant difference in temperature between day and night in desert ecosystems.

Greatest biodiversity

Tropical rain forests have the highest diversity of species compared to all other biomes combined.