What is Ecology?

Origin of the word…ecology Greek origin OIKOS = household LOGOS = study of… Study of the house/environment in which we live.

Ecology is study of interactions between non-living components in the environment… light water wind nutrients in soil heat solar radiation atmosphere, etc. AND…

Living organisms… Plants Animals microorganisms in soil, etc.

To study Ecology involves… For non-living (abiotic) Climatology Hydrology Oceanography Physics Chemistry Geology soil analysis, etc. For living (biotic) animal behavior Taxonomy Physiology mathematics (population studies) etc.

Ecology… views each locale as an integrated whole of interdependent parts that function as a unit. tundra caribou

The interdependent parts are…

Nonliving dead organic matter nutrients in the soil and water. Producers green plants Tundra

Consumers herbivores and carnivores Decomposers fungi and bacteria Tundra Caribou

ECOLOGY: Levels of Organization - a hierarchy of organization in the environment

Levels of organization - Terms Biosphere Surface of the earth Composed of many ecosystems Ecosystem Large or small as we decide Backyard, OMelveney Park, Hedge along Room 110, etc.

Levels of organization - Terms Population – one species live in one place at one time Community – All populations (diff. species) that live in a particular area.

Levels of organization - Terms Habitat – physical location of community Organism – simplest level of organization

Very complex Can contain 100s to 1000s of interacting species.

THEN… Ecology is an integrated and dynamic study of the environment.

Ecological Niche A plant's or animal's ecological niche is a way of life that is unique to that species. Niche and habitat are not the same. While many species may share a habitat, this is not true of a niche. Each plant and animal species is a member of a community. The niche describes the species' role or function within this community.

For example, the red fox's habitat, which might include forest edges, meadows and the bank of a river, is shared with many animals. The niche of the red fox is that of a predator which feeds on the small mammals, amphibians, insects, and fruit found in this habitat. Red foxes are active at night. They provide blood for blackflies and mosquitoes, and are host to numerous diseases. The scraps, or carrion, left behind after a fox's meal provide food for many small scavengers and decomposers. This, then, is the ecological niche of the red fox. Only the red fox occupies this niche in the meadow-forest edge communities. In other plant communities different species of animal may occupy a similar niche to that of the red fox.

Key Concepts Community structure Roles of species Species interactions Changes in ecosystems Stability of ecosystems

Ecological Concepts Limiting FactorsAny factor whose shortage or absence restricts species success. Range of ToleranceRange of conditions an organism can survive in. Temperature pH

Community Structure: Appearance and Species Diversity Stratification Species diversity Niche structure Edge effects Fig. 8-2 p. 166

Three Factors Affecting Biodiversity Latitude(terrestial)- the closer to the equator, the higher the biodiversity Highest species diversity in tropics; lowest in polar regions Depth(aquatic)- biodiversity increases with depth 2000 m then begins its decrease Pollution- as levels increase, biodiversity decreases Fig. 8-3 p. 167 AntsBirds Species diversity ,0004,0006,000 Depth (meters) 02,0004,0006,000 Depth (meters) CoastDeep SeaCoastDeep Sea SnailsTube worms

General Types of Organisms Native-organisms that are naturally found in an ecosystem; Nonnative (Exotic/ Invasive/Alien)- any organism that is not found naturally in an ecosystem; usually transported in by humans Indicator- organisms that serve as early warnings of damage to a community Keystone- organisms whose role in more important than their numbers or biomass; 1. Strong interactions with other species affect the life of others 2. Process out materials out of proportion to their numbers or biomass

Competition CompetitionTwo organisms compete to obtain the same limited resource, and both are harmed to some extinct. IntraspecificMembers of same species competing for resources. InterspecificMembers of different species competing for resources. The more similar the competing species, the more intense the competition.

Intraspecific Competion Ex. Grasshoppers: Out competing other hoppers Eating Grass

Interspecific Competion Ex. Large predators Out competing smaller carnivores for food Canids vs Smaller Foxes and Weasels

Competition Competitive Exclusion Principle - No two species can occupy the same ecological niche in the same place at the same time. Less fit species must evolve into a slightly different niche.

Resource Partitioning Fig. 8-9 p. 175; Refer to Fig p. 152 & Fig p. 175 Overlapping Niche of 2 species creates competition Over time, species evolve and become specialized

Kinds of Organism Interactions PredationOne animal kills/eats another. Predator benefits from food. Prey adaptation is manifested in a higher reproduction rate. Prey species benefits by eliminating non-adaptive genes from the gene pool. Poorly adapted predators are less likely to obtain food and thus pass on non-adaptive genes. Natural Selection Lab

Symbiotic Relationships SymbiosisClose, physical relationship between two different species. At least one species derives benefit from the interaction. ParasitismOne organism (parasite) living in or on another organism (host), from which it derives nourishment. EctoparasitesLive on hosts surface. Fleas EndoparasitesLive inside host. Tapeworms

Parasitism

Symbiotic Relationships CommensalismOne organism benefits, while the other is unaffected. Remoras and Sharks MutualismBoth species benefit. Obligatory in many cases as neither can exist without the other. Mycorrhizae: symbiotic association of the mycelium of a fungus with the roots of certain plants, such as conifers, beeches, or orchids

Commensalism Clown Fish/Anemone Barnacles on Whale Remoras and Sharks

Mutualism Mycorrhizae Senti Cacti/Moths

Type of relationship Species harmed Species benefits Species neutral Commensalism Parasitism Mutualism = 1 species

Succession SuccessionA series of regular, predictable changes in the structure of a community over time. Activities of organisms change their surroundings and make the environment suitable for other kinds of organisms. Climax communityStable, long-lasting community, primarily determined by climate. Mature community

Succession Primary SuccessionBegins with bare mineral surfaces or water and total lack of organisms. No soil present to begin with! Secondary SuccessionBegins with disturbance of an existing ecosystem. Much more commonly observed.

Primary Succession Terrestrial Primary Succession Pioneer Community: Collection of organisms able to colonize bare rock (i.e. lichens, mosses). Lichens help break down rock, and accumulate debris helping to form a thin soil layer. Soil layer begins to support small life forms.

Terrestrial Primary Succession Lichen community replaced by annual plants. Annuals replaced by perennial community. Perennial community replaced by shrubs. Shrubs replaced by shade intolerant trees. Shade intolerant trees replaced by shade tolerant trees. Stable, climax community often reached. Successional (seral) StageEach step in the process.

Terrestrial Primary Succession

Climax Community Characteristics Maintain species diversity for extended period. Multiple specialized ecological niches. High level of organism interactions. Nutrients recycled and biomass levels remain constant. Last stage of succession

Aquatic Primary Succession Except for oceans, most aquatic systems are considered temporary. All aquatic systems receive inputs of soil particles and organic matter from surrounding land. Gradual filling of shallow bodies of water. Roots and stems below water accumulate more material. Wet soil established.

Aquatic Primary Succession

Secondary Succession Occurs when an existing community is disturbed or destroyed. With most disturbances, most of the soil remains, and many nutrients necessary for plant growth may be available for reestablishment of the previous ecosystem. Nearby undamaged communities can serve as sources of seeds and animals. Tends to be more rapid than primary growth.

Terrestrial Secondary Succession

Secondary Succession

Secondary Succession of a Beaver Pond

Modern Concepts of Succession and Climax As settlers changed original ecosystems to agriculture, climax communities were destroyed. Many farms were abandoned, and land began to experience succession. Ecologists began to recognize there was not a fixed, pre-determined community. Only thing differentiating climax community from successional community is time scale.

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