Studying the Web of Life Ecology – the study of the interactions between organisms and their environment Environments have 2 parts: Biotic – living things in environment Abiotic – physical factors of environment (water, soil, light, temperature, etc.)

Levels of Environmental Organization Organism – single individual

Levels of Environmental Organization 2. Population – group of individuals of the same species that live together in the same area at the same time - individuals in a population compete with one another for food, nesting space, and mates

Levels of Environmental Organization 3. Community – consists of all the populations of different species that live and interact in an area - different populations in a community depend on each other for food, shelter, and many other things

Levels of Environmental Organization 4. Ecosystem – community and its abiotic environment.

Levels of Environmental Organization 5. Biosphere – part of the Earth where life exist

Living Things Need Energy All living things need energy to survive. Organisms can be divided into 3 groups based on how they obtain energy: Producers – organisms that use sunlight directly to make food Consumers – organisms that eat producers or other organisms Decomposers – organisms that get energy by breaking down dead or decaying organisms

Producers Use photosynthesis Mostly plants, but also algae and some bacteria

Consumers Cannot use sun’s energy directly Herbivore – eats plants Carnivore – eats animals Omnivore – eat both plants and animals Scavengers – feed on bodies of dead animals

Decomposers Bacteria and fungi Extract the last bit of energy from dead organisms and produce simpler materials Nature’s recyclers

Food Chains Food Chains – represents how the energy in food molecules flows from one organism to the next

Food Webs Food Web – many energy pathways between organisms

Energy Pyramid The loss of energy at each level of the food chain can be represented by an energy pyramid Each level uses 90% of the energy it obtains, so only 10% of the energy is passed along to the next level

Habitat and Niche Habitat – the environment in which an organism lives Niche – an organism’s way of life within an ecosystem Includes its habitat, food, predators, organisms with which it competes, how the organism affects and is affected by abiotic factors in its environment

Interactions with the Environment An organism interacts with biotic or abiotic factors in its environment that can control the size of its population Limiting Factors – factors that influence how large a population can grow to Ex: food, water, living space, other natural resources Carrying Capacity – the largest population that a given environment can support over a long period of time

Interactions Among Organisms 4 main ways that species and individuals affect each other: Competition Predators and Prey Symbiotic relationships Coevolution

Competition When 2 or more individuals or populations try to use the same limited resource (ex: food, water, shelter, space, sunlight, etc.) Can occur among individuals within a population Can occur between populations of different species

Predators and Prey Prey – organism that is eaten Predator – organism that eats the prey Predator Adaptations – Canines Claws Camouflage Speed Prey Adaptations – Chemical combat Camouflage Speed Trickery: false features and mimicry

Symbiosis Close, long-term association between two or more species 3 Main Groups Mutualism Commensalism Parasitism

Mutualism Symbiotic relationship in which both organisms benefit Examples: You and a species of bacteria in your intestines Coral and algae

Commensalism Symbiotic relationship in which one organism benefits and the other organism is unaffected Examples: Sharks and remoras

Parasitism Symbiotic relationship in which one organism benefits while the other organism is harmed Parasite – organism that benefits Host – organism that is harmed Example: Tomato hornworm and wasps

Coevolution Long-term change that takes place in two species because of their close interactions with one another Flowers and their Pollinators Acacia Trees and Acacia Ants Yucca Moth and Yucca Plants