ESS Topic 2: Ecology

Population Growth

100

State the graph type that demonstrates exponential growth, where population grows rapidly without constrictions 

J Curve

200

Describe the importance of keystone species 

They regulate populations, support ecological processes, and enhance habitat diversity, critical for ecosystem resilience.

300

Distinguish between Density Dependent and Density Independent Factors

Density-Dependent Factors:

• Competition for Resources: As populations grow, competition for food, water, and space increases, reducing growth rates through malnutrition, lower reproduction, and higher mortality.
• Increased Predation: Higher densities make species more visible to predators, helping balance prey populations with the ecosystem’s carrying capacity.
• Disease Transmission: High density accelerates the spread of disease, reducing population sizes, especially when individuals are weakened by resource competition.

Density-Independent Factors:

• Natural Disasters: Events like wildfires and floods reduce population sizes regardless of density.
• Climatic Changes: Extreme weather (e.g., droughts, cold snaps) affects survival across all individuals.

400

Distinguish between abiotic and biotic factors in distribution of population

Biotic
-Competition
-Predation
-Disease

Abiotic
-Temperature
-Water
-Light
-Altitude

500

Evaluate the use of Dichotomous Keys: 

Pro's (200 points max)
-Easy to use
-Easy to construct
Cons (300 points max)
-Organisms can look very different depending on life stage
-May require prior knowledge of terminology
-Parts of organisms can look damaged

Energy and biomass

100

State a transformation in an Ecosystem

• Photosynthesis: Producers (plants) capture sunlight and convert it into chemical energy.
• Energy Flow Through Trophic Levels: Chemical energy is passed through food webs as organisms consume one another.
• Heat Loss: At each trophic level, some energy is lost as heat, making energy transfers less efficient with each level.

200

Describe how a pyramid of energy differs from a pyramid of number.

A pyramid of energy shows how much energy is available at each trophic level in an ecosystem, while a pyramid of numbers shows how many individual organisms are present at each level.

300

Explain the Importance of Ecological Pyramids 

Ecosystem Analysis
Conservation and Management
Educational Tool

400

Distinguish between greenhouse effect and enhanced greenhouse effect 

Greenhouse effect = natural warming of Earth

Enhanced greenhouse effect = extra warming caused by humans

500

To what extent does Louisa contribute to class?

Pro's

-She's an artist

Con's
-Not too bright
-Really special
-Low IQ

Biogeochemical cycles

100

Define what a Carbon sink is

Places where carbon is stored, such as oceans (largest sink), forests, soil, fossil fuels, and the atmosphere.

200

Describe Carbon Sequestration 

The process of capturing and storing atmospheric CO₂ in solid or liquid forms, reducing greenhouse gases in the atmosphere and helping mitigate climate change.

300

Explain the benefits of No Till Farming

Soil Structure Preservation 

Reduced Soil Erosion 

Enhanced Water Retention 

Increased Carbon Storage

400

Distinguish between Carbon Sink and Carbon Store

Stores: Ecosystems with balanced carbon inputs (photosynthesis) and outputs (respiration) act as stable carbon stores, holding carbon in biomass and soil without net accumulation or release

Sinks: Ecosystems absorb more CO₂ than they release

500

To what extent are food chains useful in representing energy flow in ecosystem

Food chains show a simple, linear flow of energy

Easy to understand basic relationships

Oversimplified

Most ecosystems have complex food webs, not chains

They don’t show all feeding interactions

Climate and biomes

100

State the biome characterized via 

Long, cold winters, short summers, and a dominant landscape of coniferous evergreen trees

200

Describe the effects of acidification on marine ecosystem

Lowers seawater pH
Reduces carbonate ions 

300

Explain the impacts of Urbanization (HL)

• Disruption of biogeochemical cycles.
• Fragmentation and loss of habitats, threatening species and leading to potential ecosystem collapse.
• Alteration of local climates, creating urban heat islands.
• Interruption of natural water flows and increased pollution.

400

Distinguish between tropical and temperate rainforests

Tropical rainforest:

• high temperatures (average 26 C )
• high rainfall (over 2500 mm yr -1)
• near the equator
• high light levels throughout the year
• all-year round growing season
• high levels of photosynthesis

Temperate forest:

• seasonal weather (hot summers/cold winters)
• rainfall average between 500-1500 mm yr-1
• productivity lower than rainforest
• mild climate, lower average temperature / lower rainfall

500

To what extent is human life activity responsible for disruption in carbon cycle

Pro's

• Burning fossil fuels increases CO₂ levels

• Deforestation reduces carbon absorption

• Agriculture and industry release greenhouse gases

• Leads to climate change and imbalance
  
  

Con's

• Natural processes also affect carbon cycle (e.g. respiration, volcanoes)

• Some carbon is naturally stored and recycled

• Ecosystems can partly regulate themselves

Zonation

100

State the two types of Transects

Line & Belt

200

Describe the difference between line transects and belt transects

Line Transects:

• A line (string or tape) is laid across a habitat

• Only record species that touch the line

• Quick and simple, but less detailed

Belt Transects:

• A strip of defined width along a line is studied

• Record all species within the belt

• More detailed, gives better data on abundance and distribution

300

Explain how a bare area can transform into a forest

• First, pioneer species like moss and lichens grow

• They help form soil as they die and decompose

• Small plants like grasses and shrubs grow next

• Trees and bigger plants grow last 

400

Distinguish between primary and secondary succession

Primary succession begins on bare, lifeless rock without soil, making it extremely slow, whereas secondary succession begins after a disturbance in an area that already has soil and previous life, allowing for much faster recovery.

500

To what extent does Ana change the ecosystem of our classroom

Pro's
-Is sometimes funny

Con's
-Everything is a con,

She negatively affects our ecosystem