Introduction to Ecology

Ecology

• Ecology studies how organisms (animals, plants, microbes) interact in and with the natural world
• Ecology studies how organisms interact with living and nonliving things surrounding them

Origin of the Word "Ecology"

• The term has a Greek origin
• OIKOS translates to household
• LOGOS translates to "study of"
• Ecology involves studying the "house/environment" where interactions, including those within the living organisms and their nonliving environment, occur

History of Ecology

• In 1859, St. Hilaire, a French Zoologist, used the word 'ethology' for the study of organisms related with the environment
• In 1866, Ernst Haeckel, a German biologist, first defined the term 'ecology'
• 'Ecology' comes from the Greek words 'Oikos' (house or dwelling place) and 'logos' (discourse)

Types/Subdivisions of Ecology

• Autecology is the study of an individual organism, species, or population in relation to their environment
• Autecology is comparatively simple, experimental, and inductive and can be studied in a laboratory using conventional mathematical tools
• Synecology studies groups of organisms, species, or communities in relation to their environment
• Synecology is complex, philosophical, and deductive and refers to the interaction of a whole system

Classification of Ecology/Ecological Research Areas

• Global Ecology examines the influence of energy and materials on organisms across the biosphere
• Landscape Ecology focuses on the exchanges of energy, materials, and organisms across multiple ecosystems
• Ecosystem Ecology emphasizes energy flow and chemical cycling among the various biotic and abiotic components
• Community Ecology deals with the whole array of interacting species in a community
• Population Ecology focuses on factors affecting population size over time
• Organismal Ecology studies how an organism's structure, physiology, and (for animals) behavior meet environmental challenges

Abiotic vs Biotic

• Abiotic factors are non-living components of the environment like air, water, and soil
• Biotic factors are living components of the environment like plants, animals, fungi, viruses, and bacteria

Classification of Living Things

• Living things are classified into 7 levels: kingdom, phylum, class, order, family, genus, and species
• General groupings include plant or animal
• Each has a common name
• Kingdom Plantae consists of multi-celled organisms that grow from embryos as a result of sexual fusion of male and female cells
• Kingdom Animalia is made up of multi-celled organisms developing from an embryo after egg fertilization by sperm
• Genus and species are used to form a Latin Name

The Organization of Life

• Species are groups of organisms that only reproduce within themselves
• Populations are members of the same species in the same area
• Communities are all of the species that occupy an area
• Ecosystems include all of the living and nonliving things that occupy an area
• Biomes are regions characterized by climate, dominant plants, and animals
• A Biosphere is any region of the planet that supports life

Examples of Organization

• Species: Dragonflies
• Population: Dragonflies in the AHS pond
• Community: All species in the AHS pond
• Ecosystem: Includes the abiotic and biotic aspects of the AHS pond
• Biome: Temperate Deciduous Forest
• Biosphere: Earth areas that support life

Adaptations

• Adaptations can be physical or behavioral features that help the organism survive, such as beak and teeth shapes
• Camouflage and bright coloring are also useful for survival
• Habitat adaptations are also important

Habitat vs Niche

• A habitat is the specific environment that an organism calls home or its dwelling place
• For example, a pond is the dragonfly's habitat
• A niche is the specific ROLE that an organism plays in its environment
• No two species hold the exact same niche
• For example, owls live in the forest, are nocturnal, and prey upon small mammals

Ecosystem Services

• This is a modern system for giving economic value to the environment

Requirements for an Ecosystem

• There must be a constant flow of energy into the ecosystem
• There must be a cycle of materials between living and nonliving organisms

Producers: Feeding Relationships in an Ecosystem

• Autotrophs produce their own food through photosynthesis
• They form the base of any food chain or food web

Heterotrophs: Feeding Relationships in an Ecosystem

• Heterotrophs are also known as Consumers
• These organisms cannot produce their own food and they consume their food
• Herbivores are animals that feed on plants, for instance, deer
• Carnivores are animals that feed on other animals, for instance, wolves

More Heterotrophs

• Omnivores eat both plants and other animals, for example, humans
• Decomposers break down dead or decaying organic matter and return the nutrients to the soil, such as bacteria and fungus
• Scavengers feed off of dead organisms, for instance, crows

Ecosystem Dynamics

• In any ecosystem, the growth and survival of organisms depend on the physical conditions and on the available resources
• Competition is the struggle for resources among organisms
• Limiting factors in the environment limit the size of populations, such as availability of food, space, or water

Carrying Capacity

• Carrying capacity is the amount of organisms that can survive in the ecosystem
• Limiting factors determine the carrying capacity of an area
• Populations will continue to grow until they have reached their carrying capacity

Symbiotic Relationships

• Symbiotic relationships include the close association between 2 organisms
• Parasitism occurs when one organism benefits, and another is harmed (+,-).
• For example, a deer tick on a dog
• Commensalism occurs when one organism benefits, and the other is neither harmed nor helped (+,0).
• For example, a shark with pilot fish or owl in a tree
• Mutualism occurs when both organisms benefit (+,+).
• For example, a cleaner shrimp or clownfish in an anemone

Pyramid of Life + Energy/Biomass

• Trophic levels include, from the bottom to top of the pyramid, producers, primary consumers, secondary consumers, and tertiary consumers
• Energy or biomass decreases at each level of the food chain
• Fewer organisms can be supported at each level

Succession

• Succession is the aging of an ecosystem
• Succession is the process by which populations in ecosystems are gradually replaced by new ecosystems
• Each community makes the environment better for the next community
• In land succession, the change in vegetation occurs as the soil matures and changes
• The soil is enriched at each stage, preparing the way for more complex plants and results in a climax community

Starting Succession

• Succession starts with the disturbance to clear the land in events such as fire and the eruption of Mt. St. Helens in May 18, 1980
• Pond Succession specifically refers to the gradual filling in of a pond over time

Cycles in Nature

• Precipitation is the falling of water back to earth
• Infiltration is when water penetrates soil and bodies of water
• Evaporation is when water changes from a liquid to gas
• Condensation is when water vapor condenses into clouds

The Carbon-Oxygen Cycle

• Carbon Dioxide is absorbed by plants in photosynthesis
• Oxygen is released by plants in photosynthesis
• Oxygen is absorbed by plants and animals in cellular respiration
• Carbon Dioxide is released as a waste product during cellular respiration

Nitrogen Cycle

• Nitrogen is needed to construct protein
• Nitrogen is not in a usable form in the air
• Nitrogen fixing bacteria convert atmospheric nitrogen into a usable form for plants
• Denitrifying bacteria return nitrogen to the atmosphere
• Decomposing bacteria help in this process