Year 9 ecology and population

ecology

Biome

A large area characterized by its soil, climate, terrain, plants, and animals. Example: Desert, which has specific flora and fauna adapted to arid conditions.

Biosphere

The global sum of all ecosystems, encompassing all living beings and their relationships with the environment. Example: Earth, as it includes all land, water, and atmosphere where life exists.

Individual

A single organism that can be identified as a distinct entity. Example: A frog, representing a single member of the amphibian class.

Population

A group of individuals of the same species living in a specific area. Example: Kangaroos in an Australian grassland, interacting with each other and their environment.

Community

All living populations that interact in a particular area. Example: A forest community consisting of trees, animals, fungi, and other organisms.

Ecosystem

A community of living organisms and their non-living environment. Example: A pond, which includes aquatic plants, fish, and water chemistry.

Habitat

The specific environment in which an organism lives. Example: The arctic coastline, home to polar bears and seals.

Abiotic Factors

Non-living components of an ecosystem that influence living organisms. Examples: Soil composition, temperature, light availability, oxygen levels, pH, salinity, wind, and fire risk.

Biotic Factors

The living components within an ecosystem that interact with each other and with abiotic factors. Examples: Plants, animals, fungi, protists, and bacteria.

Trophic Levels

The hierarchical levels in an ecosystem, from producers to apex predators. Energy Flow: Arrows in a food web indicate the direction of energy transfer from food to consumer.

Producers

Organisms that produce their own food through photosynthesis, forming the base of the food chain.

Consumers

Organisms that consume other organisms for energy, categorized into primary, secondary, and tertiary consumers.

Apex Predators

Top-level predators with no natural enemies, crucial for maintaining the balance of ecosystems.

Chloroplasts

Organelles in plant cells where photosynthesis occurs, containing chlorophyll.

Chlorophyll

The green pigment that absorbs sunlight, essential for converting solar energy into chemical energy.

Mutualism

Both species benefit from the interaction. Example: Bees pollinating flowers while feeding on nectar.

Commensalism

One species benefits while the other is neither helped nor harmed. Example: Barnacles attaching to a whale.

Competition

Organisms vie for the same resources, such as food or habitat. Example: Two species of birds competing for nesting sites.

Parasitism

One organism benefits at the expense of another. Example: Ticks feeding on a mammal.

Predation

One organism kills and consumes another. Example: A lion hunting a zebra.

Exponential Growth

Rapid increase in population size when resources are unlimited.

Logistic Growth

Population growth that starts rapidly but slows as it approaches carrying capacity.

Carrying Capacity

The maximum population size that an environment can sustain, influenced by resource availability.

Limiting Factors

Biotic or abiotic factors that restrict population growth, such as food scarcity or extreme weather.

Using Quadrats to measure population sizes

Used for slow moving + sedentary species Uses systematic counting of a few quadrats (small portion of study area) and uses that to find total population

Calculate population sizes using the Quadrat formula

(Average population per quadrat x total study area)/ area of each quadrat

Describe and apply the Capture – recapture method

Used for mobile animals, estimates the number of animals in a population. A sample of animals is captured, marked in a harmless way, and then released back into the environment. After some time, another sample is recaptured. Scientists count how many animals in the second sample are marked. They use this data in the formula; (first capture x second capture)/ number marked in the 2nd capture

The process of photosynthesis can be summarized by the equation: $$6CO2 + 6H2O \rightarrow C_6