Biology Abitur Lernzettel / Biology exam preparation -
Topics for Q2 - Ecology, plant structure, species interactions
and nutrient cycles
Table of Contents
Ecological Rules and Adaptations
Bergmann’s rule and body size adaptation
Allen’s rule and extremity size
Other ecological rules
Reproductive Strategies
K-strategy and population stability
r-strategy and rapid reproduction
Population Ecology
Density-dependent factors
Density-independent factors
Exponential and logistic growth
Ecological Niche
Definition of ecological niche
Role of species in ecosystems
Plant Structure and Photosynthesis
Leaf structure and function
Chloroplast structure
Photosynthesis process
Photosynthesis Adaptations
C3 plants
C4 plants
CAM plants
Photorespiration
Ecological Tolerance
Tolerance ranges and optimum
Eurytopic and stenotopic species
1
,Plant Adaptations to Environment
Hygrophytes and water-rich environments
Xerophytes and dry environments
Other plant adaptations
Thermoregulation in Animals
Homeothermic organisms
Poikilothermic organisms
Species Interactions
Intraspecific relationships
Interspecific relationships
Predator-prey dynamics
Lotka-Volterra rules
Ecosystem Development
Primary succession
Secondary succession
Stages of ecosystem development
Nutrient Cycles
Nitrogen cycle
Role of bacteria and plants
Ecological Methods
Qualitative analysis
Quantitative measurements
Sampling techniques
2
, 1. Bergmannsche rule
Definition: Bergmann’s rule states that individuals of the same species (or related species) tend to
have larger body sizes in colder climates compared to those in warmer regions.
Reason for the rule: Larger animals have a more favorable surface-to-volume ratio, which helps them
store heat more efficiently, allowing them to survive better in colder climates. They can store more
heat, so they are more likely to live in cooler regions.
Examples: Larger deer species in colder regions of North America and Europe compared to smaller
species or populations in warmer areas.
Exceptions and criticisms: The rule is not universal. Some species show opposite patterns or are
influenced by other ecological and evolutionary factors.
2. Allensche rule
Definition: Allen’s rule states that animals of the same species have shorter extremities (arms, legs,
ears, tails, etc.) in colder climates compared to their relatives in warmer regions.
Reason for the rule: Shorter extremities reduce the surface area relative to the volume, minimizing
heat loss and improving heat retention in colder environments. Like Bergmann’s rule, this means
they can store more heat in their body and can therefore survive in cooler temperatures.
Examples: Foxes or hares with shorter ears and limbs in Arctic regions compared to those in warmer
areas.
Exceptions: Like Bergmann’s rule, there are species where this rule does not apply, which can be
attributed to different ecological adaptations or evolutionary influences.
3. Reproductive strategies: K- and R-strategies
K-strategies:
-K-strategists follow a strategy of slower reproduction with fewer, but more viable offspring
-K-strategists invest more resources in raising fewer offspring, which have a higher chance of survival
-K-strategists are often found in stable environments with limited resources and intense competition
-K-strategists have a low reproductive rate and a high life expectancy
-K-strategists are characterized by a large body size and few offspring with intensive care
-Reproduction in K-strategists occurs later in life, as they pursue a long-term survival strategy
3
Topics for Q2 - Ecology, plant structure, species interactions
and nutrient cycles
Table of Contents
Ecological Rules and Adaptations
Bergmann’s rule and body size adaptation
Allen’s rule and extremity size
Other ecological rules
Reproductive Strategies
K-strategy and population stability
r-strategy and rapid reproduction
Population Ecology
Density-dependent factors
Density-independent factors
Exponential and logistic growth
Ecological Niche
Definition of ecological niche
Role of species in ecosystems
Plant Structure and Photosynthesis
Leaf structure and function
Chloroplast structure
Photosynthesis process
Photosynthesis Adaptations
C3 plants
C4 plants
CAM plants
Photorespiration
Ecological Tolerance
Tolerance ranges and optimum
Eurytopic and stenotopic species
1
,Plant Adaptations to Environment
Hygrophytes and water-rich environments
Xerophytes and dry environments
Other plant adaptations
Thermoregulation in Animals
Homeothermic organisms
Poikilothermic organisms
Species Interactions
Intraspecific relationships
Interspecific relationships
Predator-prey dynamics
Lotka-Volterra rules
Ecosystem Development
Primary succession
Secondary succession
Stages of ecosystem development
Nutrient Cycles
Nitrogen cycle
Role of bacteria and plants
Ecological Methods
Qualitative analysis
Quantitative measurements
Sampling techniques
2
, 1. Bergmannsche rule
Definition: Bergmann’s rule states that individuals of the same species (or related species) tend to
have larger body sizes in colder climates compared to those in warmer regions.
Reason for the rule: Larger animals have a more favorable surface-to-volume ratio, which helps them
store heat more efficiently, allowing them to survive better in colder climates. They can store more
heat, so they are more likely to live in cooler regions.
Examples: Larger deer species in colder regions of North America and Europe compared to smaller
species or populations in warmer areas.
Exceptions and criticisms: The rule is not universal. Some species show opposite patterns or are
influenced by other ecological and evolutionary factors.
2. Allensche rule
Definition: Allen’s rule states that animals of the same species have shorter extremities (arms, legs,
ears, tails, etc.) in colder climates compared to their relatives in warmer regions.
Reason for the rule: Shorter extremities reduce the surface area relative to the volume, minimizing
heat loss and improving heat retention in colder environments. Like Bergmann’s rule, this means
they can store more heat in their body and can therefore survive in cooler temperatures.
Examples: Foxes or hares with shorter ears and limbs in Arctic regions compared to those in warmer
areas.
Exceptions: Like Bergmann’s rule, there are species where this rule does not apply, which can be
attributed to different ecological adaptations or evolutionary influences.
3. Reproductive strategies: K- and R-strategies
K-strategies:
-K-strategists follow a strategy of slower reproduction with fewer, but more viable offspring
-K-strategists invest more resources in raising fewer offspring, which have a higher chance of survival
-K-strategists are often found in stable environments with limited resources and intense competition
-K-strategists have a low reproductive rate and a high life expectancy
-K-strategists are characterized by a large body size and few offspring with intensive care
-Reproduction in K-strategists occurs later in life, as they pursue a long-term survival strategy
3
