Ecology

1. Ecology Learning Goal Two Examine how coevolution has lead to interactions between members of an ecological community.

2. Ecological Interactions • Population interactions are driven by coevolution. These are genetically based adaptations in two or more interacting species.

3. Predation and Herbivory Adaptations for Feeding – Sharp fangs and claws for predators. Chemical sensors to identify food plants and specialized teeth for grinding vegetation in herbivores

4. Specialists – feed on just one or a few types of food. Generalists – feed on many types of food.

5. Defenses Against Predation and Herbivory • Cryptic Coloration – predators and prey species often display colors that help them blend into their surroundings • Aposematic Coloration – Bright colors displayed by poisonous species.

6. Mimicry • Batesian mimicry – a harmless species mimics a poisonous or unpalatable species • Mullerian mimicry – two or more unpalatable species are similar in appearnance

7. Interspecific Competition • Interference competition Individuals of one species harm individuals of another species directly. • Exploitative competition Two or more populations use the same limiting resource.

8. Competitive Exclusion • Competitive Exclusion Principle Populations of two or more species cannot coexist indefinitely if they rely on the same limiting resources and exploit them in the same way.

9. Resource Partitioning Using the same resource in different ways • Character Displacement Developing different traits in order to exploit different resources

10. Symbiotic Relationships Symbiosis – A close association between two species Commensalism – one species benefits and the other is unaffected Mutualism – both species benefit Parasitism – one species benefits and the other is harmed

14. Community Characteristics • Species Richness – number of different species types in a community. • Species Abundance – number of individuals in different populations. • Species Diversity – community characteristic that takes into account both species richness and abundance.

15. Forest A 50 Trees 10 Species 39 of one species Forest B 50 Trees 10 Species 5 of each species

16. Feeding Relationships Trophic Levels: Producers – produce their own food through photosynthesis or chemosynthesis. (autotrophs) Consumers – must eat to get their energy (heterotrophs) Decomposers – break down organic matter into its chemical components.

17. Types of Consumers • Herbivores – eat plants, also called primary consumers. • Carnivores – eat only meat, also called secondary or tertiary consumers. • Omnivores – eat both plants and meat. • Detritivores – eat dead stuff.

18. Food Chains and Webs • Food Chains – show one path of feeding relationships between organisms. • Food Webs – many interconnected food chains.

19. Community Response to Disturbance • Ecological Succession Somewhat predictable series of changes in species composition over time.

20. Primary Succession Occurs when organisms first colonize habitats without soil such as those created by lava flows and retreating glaciers.

21. Pioneer species like lichens that can grow on rock secrete mild acids that begin the process of soil formation. • As soil accumulates hardy plants like grasses, ferns, and shrubs come in. Roots break up rocks and decaying material adds to soil. • Deeper soil can hold more moisture and nutrients so larger plants can take hold; more K-selected species like trees. • This last stage is often called the climax community because it stays relatively stable until disrupted by another disturbance which may result in secondary succession.

22. Secondary Succession Occurs after existing vegetation is destroyed by environmental disturbances such as fire, storms or human activity where soil remains.

23. LG2 Terms • Coevolution – • Competitive Exclusion Principle – • Symbiotic Relationships – • Species Diversity – • Trophic Levels – • Detritivores – • Food Chains/Webs – • Ecological Succession – • Primary/Secondary Succession – • Pioneer Species –