Studying the Web of Life

Ecology – the study of the interactions between organisms and their environment

Environments have 2 parts:Biotic – living things in environmentAbiotic – physical factors of environment

(water, soil, light, temperature, etc.)

Levels of Environmental Organization

1. 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:1. Producers – organisms that use sunlight

directly to make food 2. Consumers – organisms that eat

producers or other organisms 3. Decomposers – organisms that get

energy by breaking down dead or decaying organisms

Producers

Use photosynthesisMostly 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 fungiExtract 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

resourcesCarrying 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:1. Competition2. Predators and Prey3. Symbiotic relationships4. 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 – CaninesClawsCamouflageSpeed

Prey Adaptations – Chemical combatCamouflageSpeedTrickery: false features and mimicry

Symbiosis

Close, long-term association between two or more species

3 Main Groups1. Mutualism2. Commensalism 3. 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

Yucca Moth and Yucca Plants

Flowers and their Pollinators

Acacia Trees and Acacia Ants