Interactions of Living Things

What is Ecology?
 The study of the interactions between organisms and their environment
 Interactions between organisms is not simply who eats who but varied, some good some bad

2 parts of ecology
 Biotic aspect
 The living part of the environment
 Animals, plants, insects, humans
 Abiotic aspect
 The non-living part of the environment
 Physical factors
 Rocks, water, soil, light, temperature

Organization in the Environment
 Organism
 Populations
 Communities
 Ecosystems
 Biosphere
 Single animal
 Group of the same animal
 Different populations in the same area
 Includes the abiotic factors
 Earth where life exists

The Energy Connection
 All living things need energy to survive
 Organisms are divided into groups based on how they get energy
 Producers
 Consumers
 Scavengers
 Decomposers

Producers
 Make their own food/energy
 Use the sun to go through the process of photosynthesis
 Includes plants, algae and some bacteria

Consumers
 Can ’ t make their own energy, get it by eating producers or other consumers
 Primary consumer – eats the producer
 Secondary consumer – eats a consumer
 Herbivore – eats only plants
 Carnivore – eats only animals
 Omnivores – eats both plants and animals

Scavenger vs. Decomposer
 Scavengers eat dead animals for energy
 Examples include turkey vultures
 Decomposers get energy by breaking down the remains of dead organisms
 Recyclers, bacteria and fungi

Food Chains and Webs
 Food chains represent how energy flows from one organism to the next
 Rare in nature because animals usually eat more than one organism
Food webs represent many pathways that energy flows in an ecosystem

Energy Pyramids
 Represents the loss of energy by each organism in a food chain or web

Habitat vs. Niche
 Habitat – the environment in which an organism lives
 When things like deforestation, building of roads and buildings occur, habitats are being destroyed
 Niche – organisms way of life in the ecosystem
 Includes its habitat, food, predators, competitors and abiotic factors

Niche of the Gray Wolf
 Consumers
 Carnivores, eating moose, deer, reindeer, sheep and small animals such as birds and snakes
 Social Structure – hunt in packs
 Nurture and teach their young
 Important in population control

Interactions
 Most living things produce more offspring than will survive but abiotic and biotic factors will control the population size
 Example: frogs

Limiting factors
 Populations cannot grow indefinitely because the environment contains only so much food, water, living space and other resources
 When one or more becomes scarce, it becomes a limiting factor

Carrying Capacity
 The largest population that a given environment can support over a long period of time
 When the population gets larger than carrying capacity, limiting factors will cause the population to get smaller

Competition
 Can occur among individuals within a population or between populations
 Competition for resources, mates, space

Predator and Prey
 Prey – the organism that is eaten
 Predator – the organism doing the eating
 Adaptations
 Predator – speed or ambush prey
 Prey – run away, camouflage, poisonous, bright colors, groups

Symbiosis
 Long term, association between two or more species
 3 types
 Mutualism
 Commensalism
 Parasitism

Mutualism
 Both organisms benefit
 Insects pollinating flowers

Commensalism
 One organism is benefiting and the other is unaffected
 Clown fish and sea anemone

Parasitism
 One organism is harmed and the other is benefiting
 Parasitebenefits
 Host - harmed

Coevolution
 Long term change that takes place in two species because of their close interactions with each other
 Herbivores evolving with the plants they eat
 Flowers and their pollinators