Poopulation Ecology and Community Ecology

Introduction to population ecology.
- Transition into community ecology.
- Emphasis on "trade-offs".

Definition and Importance
- Organisms face limited energy resources, which is the currency of nature.
- Trade-offs dictate where and how organisms allocate energy in their lives.
Decision Making in Organisms
- Even organisms without brains make choices based on energy allocation.
- Energy allocation areas include: growing, reproducing, repairing, moving, sleeping, foraging, food storage.
- Trade-offs limit the extent of activities possible due to energy constraints.

Evolutionary Selection
- Evolution promotes strategies for optimizing energy allocation and minimizing trade-off costs.
K and r Strategies
- r-Strategy: Species have high reproductive rates (r) with little parental care.
- K-Strategy: Species invest more in the survival of fewer offspring, tending to limit reproduction rates
- Italicized 'r' and 'k' as growth coefficients central to these strategies.
Continuum of Strategies
- Reproductive strategies exist on a continuum, with various adaptations observed in species.
- Example of reproductive output in frogs.

General Overview of Parental Care
- Higher parental care correlates with fewer offspring.
- Forms of parental care include:
- Territoriality for gestating offspring.
- Protecting eggs from drying or predation.

Introduction to Population Dynamics
- Focus on colonization and extinction in small populations.
- Development of metapopulation theory.

Definition
- A meta-population consists of smaller populations connected through dispersal.
Classic Study Example
- Small populations are not always doomed; they can persist through connectivity with larger populations.
Concept of Connectivity
- Importance of corridors in conservation biology to connect fragmented habitats.
- Successful connectivity examples, such as in the Rocky Mountains.

Impact of Habitat Fragmentation
- Fragmented habitats lead to isolation and affect reproductive success.
- Animals may not be capable of navigating open spaces between patches of habitat.

Concept of Speciation
- Population isolation and habitat fragmentation can slow down the speciation process.
- For organisms, factors affecting interactions include barriers and genetic mixing with neighboring populations.

Definition of Niche
- Niche: How an organism uses its environment and interacts within its ecosystem.
Realized vs. Fundamental Niche
- Fundamental Niche: An organism's theoretical ecological role.
- Realized Niche: Actual ecological role shaped by competitive interactions.

Overview of Community Interaction Types
- Each species experiences distinct costs and benefits in relationships with others.

Antagonistic Interactions
- Competition: Negative for both parties involved.
- Predation: Positive for predator, negative for prey.
- Herbivory and Parasitism: Negative for prey/plant but not always fatal.

Intraspecific vs. Interspecific Competition
- Intraspecific: Competition within the same species.
- Interspecific: Competition among different species.
Competitive Exclusion Principle
- One species excludes another from resource access.
Resource Partitioning
- Organisms adapt to reduce competition by utilizing different resources.

Overview of Predation
- Predators and prey interact in complex ecosystems, determining balance in populations.
Steve Huffaker’s Work (1950s)
- Introduced the concept of refugia, enhancing prey survival against predators.
Importance of habitat complexity for maintaining diverse communities.

Definition
- Mutualism: Both species benefit, sharing costs and advantages in the relationship.
- Symbiotic relationships typically evolved from mutualistic interactions.
Ecological Time and Dynamics
- Discuss ecological dynamics regarding parasites, predation, and the broader implications on ecological systems.