ecological communities

Question 1

What is batch fecundity?

Answer 1

Batch fecundity is the number of offspring produced in a single mating event.

Question 2

What is life history theory?

Answer 2

Life history theory is an analytical framework used to study the strategies and characteristics that define an organism’s life cycle, including traits such as reproductive strategies and growth patterns.

Question 3

What is the difference between r-selected and K-selected species?

Answer 3

• r-selected species: Have short lifespans, produce many offspring, and grow quickly. They are typically small and have large population sizes with limited distribution.
• K-selected species: Have longer lifespans, produce fewer offspring, and live near the carrying capacity of their environment.

Question 4

Why are otoliths used for ageing fish?

Answer 4

Otoliths have distinct growth rings, making them useful for aging short-lived or young individuals. They need to be validated with individuals of known age, and results can differ between lab and in situ environments.

Question 5

What is the difference between Chondrichthyes and Osteichthyes?

Answer 5

• Chondrichthyes: Cartilaginous fish, primarily composed of cartilage (e.g., sharks).
• Osteichthyes: Bony fish, with a skeleton composed of bone tissue.

Question 6

How are sharks aged?

Answer 6

Sharks lack otoliths, so they are aged using their vertebrae. This method is less refined than using otoliths because vertebrae are made of softer material.

Question 7

How are Greenland sharks aged?

Answer 7

Greenland sharks cannot be aged using vertebrae (as they are too soft). Instead, carbon dating of proteins in the shark’s eyeball is used. Greenland sharks grow <1 cm per year and have a very slow metabolism, with a top speed of <2.9 km/h.

Question 8

What defines an ecological community?

Answer 8

An ecological community is the complete set of organisms from all species living in a particular place at a particular time.

Question 9

How are ecological communities compared?

Answer 9

• Species richness: Number of species present
• Species density: Number of individuals per unit area
• Diversity and evenness: Measures variation and distribution of species
• Beta diversity: Comparison of diversity across habitats
• Trait-based analyses: Including functional richness, evenness, divergence, diversity, and originality
• Species-environment relationships: Analyzed through redundancy analysis or canonical discriminant analysis