IB Ecology test

Ecology

The study of the interactions between organisms and their enviroment

Levels of organization

Organelle, cells, tissues, organs, organ systems, organisms, population, communities, ecosystem and biosphere

Biotic factors

Fungi, Bacteria, Plants, Protists, Archaea, Animals

Abiotic factors

air, salinity, soil, temp, light, water, minerals, pH, humidity

Biome

Land biomes

Rain forests, savannas, deserts, grassland, tundra, taiga

Aquatic biomes

lakes and ponds, rivers and seas, oceans, estuaries, coral reefs, wetlands, mangroves, and intertidal zones.

Photic and aphotic zones

the photic zone is the zone where light can be received (where most of the ocean’s biomass lives)

The aphotic zone is the zone where no light is received (where most of the ocean’s water lies beneath the photic zone)

Energy in ecosystem: source

The sun

How energy moves through ecosystems

Energy is transferred between organisms in food webs from producers to consumers.

Energy pyramid

producers, primary consumers, secondary consumers, tertiary consumers.

trophic levels

Herbivores, organisms that consume plants and other autotrophs, are the second trophic level. Both omnivores and carnivores, meat eaters, are the third trophic level. Decomposers occupy the last trophic level or the top of the ecological pyramid.

Decomposers

organisms that break down dead or decaying organisms; they carry out decomposition, a process possible by only certain kingdoms, such as fungi.

Autotroph & heterotroph

Autotrophs are producers who prepare their own food. (plants, algae, some bacteria)

Heterotrophs are consumers who depend on other sources for their food. (animals, most bacteria, fungi)

Food chains & food webs

A food chain outlines who eats whom.

A food web is all of the food chains in an ecosystem.

Trophic level

The trophic level of an organism is the position it occupies in a food web.

Biomass pyramid

the representation of total living biomass or organic matter present at different trophic levels in an ecosystem.

Primary productivity

the production of chemical energy in organic compounds by living organisms.

Primary producers convert light energy and inorganic nutrients into organic biomass.

How movement in ecosystems is different from energy

The flow of energy is inefficient, as energy is lost at each trophic level due to heat and metabolic processes. On the other hand, nutrients are continuously recycled within and between ecosystems, ensuring that they remain available in the ecosystem.

Matter cycles

can be traced from organism to organism.

water, carbon, nitrogen, and phosphorus cycles.

Carbon cycle

nature's way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again.

the human extraction and burning of fossil fuels has altered the carbon cycle over decades

Climate vs weather

Climate: patterns and averages in temp over MANY years. (more predictable)

Weather: short, hard to determine changes

3 climate zones

the polar zone, the temperate zone, and the tropical zone.

Factors that create 3 zones

based on the temperature, the amount of precipitation, and the times of year when precipitation occurs.

Why is latitude important?

help us to find out the distance of any place from the Equator

The most direct way latitude affects climate is through the amount of solar energy a place receives

Calculate population density

The formula is Dp = N / A, where N is the total number of individuals and A is the measurement of land area.

4 things that affect population growth rates

birth, death, immigration, and emigration.

Logistic growth

S-shape

Exponential growth

J-shape

Effects on population growth

exponential: growth rate continues to accelerate forever

logistic: later growth slows to zero

Carrying capacity

The maximum number of individuals in a species that an environment can support for the long term.

Logistic growth vs Exponential growth

The type of growth curve that represents human population is logistic growth. In exponential growth, the population grows at a constant rate without any limiting factors.

Density-dependent factors

disease, competition, and predation.

Density-independent factors

factors that influence the death rates of organisms but do not affect the size, range, or number of the organisms. These factors include events like natural disasters and human activity.

Age structure diagram

An age structure diagram, or population pyramid, shows the distribution of age and sex in a population. The y-axis of the diagram shows age groups from birth to old age. The x-axis shows the population percentage.

Greenhouse effect

C02 and other gases in the atmosphere trap heat, keeping the earth warm

Major greenhouse gases

carbon dioxide, methane, nitrous oxide

Community interactions

competition, predation, and symbiosis.

Competition

a relationship between organisms that strive for the same resources in the same place.

Keystone species

an organism that helps define an entire ecosystem.

Ex: starfish, sea otters, wolves and elephants

Biodiversity

the variety of life on Earth, in all its forms, from genes and bacteria to entire ecosystems such as forests or coral reefs.

Biomes

• distance from the sea.

• ocean currents.

• direction of prevailing winds.

• shape of the land (known as 'relief' or 'topography')

• distance from the equator.

• the El Niño phenomenon.

Ecosystem services

provisioning, regulating, cultural and supporting services.

Ecological footprint

a measure that indicates how much resources from the environment are required to support a specific way of life or business.