Everything is Connected

• All living things are connected in a web of life• Ecology is the study of the interactions of organisms

with one another and with their environment• The environment can be arranged into different

levels – organism – population – communities – ecosystems - biosphere

• There are two parts of the environment: – the biotic part is all the organisms that live together and

interact – The abiotic part consists of the nonliving factors such as

water , soil, light and temperature

Levels of Environment

• Populations – each organism is part of a group of individuals of the same species that live together – individuals compete for food, living space and mates Ex. Perch in Muzzy Meadow

• Community – all the populations of species that live and interact in an area – populations depend on each other for food, shelter, etc.

• Ecosystems – made up of a community of organisms and the abiotic environment of that community

• Biosphere – part of the Earth where life exists

Living Things Need Energy

• Organisms are divided into three groups based on how they get energy

• Producers – organisms that use sunlight directly to make food – process is called photosynthesis - plants, algae and some bacterias

• Consumers – organisms that eat other organisms – Herbivore – consumers that eat only plants – ex. cows– Carnivore – consumers that eats animals – ex. coyotes– Omnivore - consumers that eat both plants and animals

– ex. Grasshopper mouse

Decomposers – organisms that get their energy by breaking down dead organisms – ex. bacteria

Food Chains and Webs

• A food chain is a diagram that shows how energy in food flows from one organism to another - few organisms eat just one kind of food so food chains are rare

• A food web is a diagram that shows the feeding relationships between organisms in an ecosystem

• An arrow goes from the organism that is the food to the organism that will eat it

• Energy moves from one organism to the next in a one – way direction

• Any energy stored in an organism’s tissues can be used by the next consumer

Energy Pyramids

• An energy pyramid is a diagram that shows an ecosystem’s loss of energy

• Less energy is available at higher levels because only energy stored in tissues of an organism can be transferred to the next level

• Gray wolves are consumers that control the population of many other animals

• Because gray wolves are predators that prey on large animals, they are at the top of the pyramid

• When gray wolves were almost wiped out, it created an overpopulation of elk – this led to overgrazing – almost all populations were affected

1. Name one biotic factor in an ecosystem. Name one abiotic factor in an ecosystem.

2. What is the difference between a population and a community?

3. What type of organism makes its own food? 4. What type of organism consumes other

animals?5. What type of organism gets energy by

breaking down dead organisms?6. What is the difference between a food chain

and a food web?

Interactions with the Environment

• Variations in sizes of populations within a community happen because everything in the environment affects every other thing

• Populations can’t grow without stopping because the environment contains a limited amount of food, water, living space and other resources

• A limiting factor is a resource that is so scarce that it limits the size of the population

• Carrying capacity – the largest population that an environment can support

• When a population grows larger that its carrying capacity, limiting factors in the environment cause individuals to die off or leave

Interactions Between OrganismsCompetition

• Four main ways that species and individuals affect each other: competition, predators and prey, symbiotic relationships and coevolution

• Competition – when two or more individuals or populations try to use the same resources, such as food, living space, water or sunlight

• Competition happens between individuals within one population and happens between populations within a community

Interactions Between OrganismsPredator and Prey

• Predator and prey – one organism eating the other – prey is the organism being eaten – predator is the organism that eats the prey

• Predator adaptations – must be able to catch their prey ex. cheetah’s speed

• Prey adaptations – methods and abilities that organisms have to keep from being eaten ex. buffalo herd

• Camouflage – one way animals avoid being eaten is to blend in with the background

• Defensive chemicals – spraying predators with irritating chemicals

• Warning coloration – predators avoid colors or patterns they associate with pain

Symbiosis

• Symbiosis is a close, long-term association between two or more species

• Individuals in a symbiotic relationship can benefit from, be unaffected by, or be harmed by the relationship

• Symbiotic relationships classified in three groups: mutualism, commensalism and parasitism

• Mutualism – both organisms benefit from the relationship ex. bacteria that lives in our intestine

• Commensalism – one organism benefits and the other is unaffected ex. sharks and remoras

• Parasitism – one organism benefits while the other is harmed – parasite is the organism benefitting and host is the organism being harmed ex. tapeworm

Coevolution

• Coevolution is the evolution of two species that is due to their mutual influence on each other, often in a way that is helpful to both species

• The ant and acacia tree have a mutualistic relationship – the ants protect the tree by attacking other organisms that come near it – the tree has special structures that make food for ants – may have coevolved into this current situation

• Flowers have changed over millions of years to attract pollinators (ex. bees)

• For example, flowers pollinated by hummingbirds make nectar with just the right amount of sugar for the bird

1. Give an example of a limiting factor in an ecosystem.

2. What is carrying capacity?3. Name one type of prey adaptation.4. What is symbiosis?5. What type of relationship benefits both

organisms?6. What type of relationship benefits one organism

and doesn’t affect the other?7. What type of relationship benefits one organism

and harms the other?

Habitat and Niche

• A habitat is the place where an organism usually lives – it provides all the resources that an organism needs to grow and survive• A niche is the role a population

plays in the ecosystem

Consumers

• There are three levels of consumers• The first group of organisms are the

primary consumers - they are also called herbivores• Secondary consumers eat the primary

consumers – they are also called carnivores• There is a third level of consumer called

the tertiary consumer - they eat the secondary and primary consumers