Ecology
Community Community Ecology - the study of all the organisms in a given area at a given time. Fig 38.8b and 38.8c
Interspecific Interactions Predation Mutualism Commensalism Parasitism Competition + + + + + 0 -
Competition
Limiting factor Interspecific competition interactions between individuals of different species when both require the same scarce resource. (greatest between organisms that obtain their food in similar ways) Competitive exclusion Fig 38.10 when 2 species are competing for a resource, the species that uses the resource more efficiently will eventually eliminate the other. But they can coexist on a long-term basis if their niches differ in one or more feat. The Niche - Image and Fig. 38.9 pattern of living (biological role) Realized niche actual niche the organism is able to occupy Fundamental niche Occupying the entire niche they are theoretically capable of using Resource partitioning - Fig 38.11 avoid competition as much as possible. Divides up resources to create two realized niches. Character displacement - Image similar species that occupy the same area has greater diffences in morphology and behavior than the same two species do when living in different habitats.
Symbiosis - Three Major Kinds of Relationships
Coevolution long-term mutual evolutionary adjustments of characteristics of members to live together.
Mutualism: both participants benefit -- Microorganisms in digestive tracts of herbivores -- Mycorrhizae = fungus + plant root - Image grow better -- Nitrogen-fixing bacteria in nodules on the roots of legumes (Image) -- Flowering plants + pollinators Fig 38.13 -- Some species of acacia + ants - Fig 38.15 food for ants/ protection for plants Parasitism: one partner benefits (parasite), other is harmed (host) Fig. 38.16a. endoparasites flukes going inside of human body ectoparasites parasites that feed on the exterior surface of organism. (living on body of something) parasitoids insects that lay eggs on living hosts. parasites nest cowbirds and European cuckoos lay their eggs in the nests of other species. The host raises the brood parasite as if it were one of their own clutches. Raises it better than their own Commensalism: one partner benefits, other unaffected -- Clownfish and sea anemone Fig 38.17 - The movie anemone has stings to protect clownfish. Clownfish eats leftovers. -- Oxpeckers and African cape buffalo Fig 38.18
Predator-Prey Interactions - A predator in action and Fig 38.20 may be cyclic in nature. Fig. 38.21 usually similar size
Predators may have special features for detection and acquisition of prey sight, hearing, smell, speed, claws, teeth, tolerance of chemicals
Plant Defenses Morphological defenses -- Thorns and spines -- Glandular hairs -- Deposition of crystals in plant's tissues Chemical defenses -- Chemical compounds Defenses in Animals Speed Fig 38.19 Claws Quills Chemicals Cryptic coloration - Image and Deceptive coloration color that blends with surrounding. Usually don't live together in groups
Aposematic coloration - Image brightly colored/ a warning Mimicry *Batesian mimicry - Fig 38.27 within members of groups -- Unprotected species resemble protected ones -- Harmful specimen is the model -- Harmless specimen is the mimic *Muellerian mimicry - Fig 38.28 several unrelated but protected animal species come to resemble one another
Community Structure
Species diversity - Image species richness relative abundance of species Dominant and Keystone Species - Image and Image and Fig 38.22- keystone species are dominant species. When they are gone, diversity decrease rather than increasing
Ecological succession, disturbance and non-equilibrium
Stability Disturbance - Image - Mount Saint Helen's - Forest fire Primary succession Image Image Movie Fig. 38.30 Fig. 38.31- occurs in a bare lifeless substrate like rocks Secondary succession - Image occurs in areas where existing community has been disturbed Changes in soil during succession