Living Environment Name___________________________

Period _____

Ecology Notes

Ecology – the study of how organisms interact with the living and nonliving things that

surround them.

Organisms are interacting with their environment all of the time, and their environment

impacts them as well.

Environment – every living and nonliving thing that surrounds an organism

Abiotic Factors – nonliving factors in the environment

Examples: temperature, humidity, precipitation, pH, composition of air (gases)

Biotic Factors – living factors in the environment

Examples: plants, animals, single-celled life forms

There are several levels of organisms within the environment. Listed from largest to

smallest they are:

Biosphere (this is the biologically inhabited portions of the planet)

Ecosystem (all of the living and non-living things that interact with one another in a

particular place)

Community (all of the different populations of organisms living in an area)

Population (all of the members of one species that live in the same area)

Organism (an individual animal, plant, or single-celled life form)

The growth of an ecosystem depends on the physical conditions and on the resources

available to the organism.

Carrying Capacity – the number of organisms of any single species that an ecosystem can

support

Competition helps keep the size of a species population under control.

Competition – the struggle for resources among organisms

Another thing that limits the size of populations in an ecosystem are called limiting

factors.

Limiting Factors – any factor in the environment that limits the size of populations

Examples: amount of oxygen, amount of sunlight, temperature, predator/prey interactions

Predator – an organism that kills and eats other organisms

Prey – an organism that is killed for food

All organisms interact and have roles they play in an ecosystem.

Ecological Niche – the role that each species plays in an ecosystem

A niche includes:

o The range of conditions that the species can tolerate

o The methods by which it obtains the needed resources

o The number of offspring it has

o Its time of reproduction

o All of its other interactions with its environment

In every ecosystem populations of all different species are linked together. Sometimes

these relationships are competitive, other times they are cooperative.

Food Chains – illustrate the relationships between the prey and predator (it shows what

eats what)

Some food chain vocabulary:

Autotroph (or Producer) – organisms that make their own food (they provide a source of

food energy for almost all other living things

Heterotroph (or Consumer) – organisms that must acquire food by consuming other

organisms

o Carnivore – heterotrophs that eat other animals

o Herbivore – heterotrophs that eat plants only

o Omnivore – heterotrophs that eat both plants and animals

o Decomposer – an organisms that consumes the wastes and dead bodies of all

organisms, they recycle materials that can be reused by producers

o Scavenger – animals that consume the carcasses of other organisms that

have been killed by predators or have died of other causes

o Parasite – organisms that attack other live organisms (called host organisms)

o Detritivore – chew or grind on detritus particles into smaller pieces, they

commonly digest decomposers that live on and in detritus particles (parts of

dead organisms converted by decomposers)

Food Web: overlapping food chains

Energy flows through ecosystems.

Energy Pyramid – a diagram that illustrates the transfer of energy through a food chain or

web.

Each block on the energy pyramid represents the amount of energy that was obtained

from the organism below it.

Levels of Consumers:

Primary Consumer – an animal that feeds on the producers in an ecosystem

Secondary Consumer – a carnivore that feeds on herbivores

Tertiary Consumer – a carnivore that feeds on other carnivores, at the top of the food

pyramid

Cycles of Matter

Living things are made mostly of oxygen, nitrogen, carbon, and hydrogen. Those elements

make up the most important compounds in living things, such as water, carbohydrates,

lipids, nucleic acids, and proteins.

Biogeochemical cycle – process in which elements, chemical compounds, and other forms of

matter are passed from one organism to another and from pone part of the biosphere to

another

Each substance travels through a biogeochemical cycle moving from the abiotic portion of

the environment, into the biotic, and then back again.

The Water Cycle

Water is one of the most important factors in maintaining life on Earth.

Water cycle – the continuous movement of water between the oceans, the atmosphere, and

land

Evaporation – changing a liquid to a gas

Condensation – changing from a gas to a liquid (clouds form when water condenses around

dust in the atmosphere)

Precipitation – liquid or solid water falling down to the Earth’s surface

Transpiration – the plants loss of water through its leaves

The Carbon Cycle

Carbon is a major component of all organic compounds and things. The cycling of

carbon through the biosphere is essential to life on Earth.

The Nitrogen Cycle

All organisms require nitrogen to make proteins and nucleic acids. The pathways

that cycles nitrogen through an ecosystem is called the nitrogen cycle.

Nitrogen fixation – the process of converting nitrogen gas to nitrogen compounds

that plants can absorb and use (this is essential because most organisms cannot use

nitrogen in its pure state, nitrogen fixing bacteria are able to convert nitrogen gas

into ammonia, then nitrite, and then nitrate which plants can use)

The Phosphorus Cycle

Phosphorus is also essential to living things. It helps form vital molecules such as DNA and

RNA. The cycling of phosphorus through an ecosystem is called the phosphorus cycle.

Symbioses

Symbiosis – a relationship where two species lives closely together

Mutualism – the symbiotic relationship in which both species benefit from the relationship

(ex. Sea anemone and clownfish)

Parasitism – the symbiotic relationship in which one organism lives on or inside another

organism and harms it (ex. Ticks on dogs)

Commensalism – the symbiotic relationship in which one organism benefits and the other is

neither helped nor harmed (ex. Barnacles on whales)

Succession

Ecological Succession – a series of gradual changes that occur in a community following a

disturbance

Primary Succession – succession that occurs in an area in which no trace of a previous

community is present

Pioneer Species – the first species to populate an area during succession

Secondary Succession – a type of succession that occurs in an area that was only partially

destroyed by disturbances

Biomes

Biomes – a large community of plants and animals that occupies a distinct region,

typically defined by their climate and dominant vegetation

Major Terrestrial Biomes

o Tropical rain forest

o Tropical dry forest

o Tropical grassland/savanna/shrubland

o Desert

o Temperate grassland

o Temperate woodland and shrubland

o Temperate forest

o Northwestern coniferous forest

o Boreal forest

o Tundra

Aquatic Ecosystems

o Freshwater

Rivers and streams

Lakes and ponds

Freshwater wetlands

o Estuary – wetlands that form where a river meets the sea, they are a

mixture of saltwater and freshwater

o Marine (saltwater)

Intertidal zone

Coastal ocean

Open ocean

Biodiversity

Biodiversity – the total of the variety of organisms in the biosphere, also called biological

diversity

As habitats are lost and species become extinct, biodiversity is reduced.

Why is biodiversity so important?

1. Ecosystems with low diversity take longer to recover from environmental changes.

2. We use organism for many things such as food and medicine; by reducing

biodiversity we are losing potentially valuable resources.

Human Impact on the Environment

Human Actions often have a negative consequence for the ecosystem.

Things that humans have done that have a negative impact are…

o Development

o Industrialization

o Pollution

o Farming

o Over hunting

o Over grazing

o Clear cutting

o Introduction of foreign species

o Soil erosion

There are things that humans are doing to reduce or repair damage to the environment.

Some examples are

o Recycling wastes

o Conserving available resources (nonrenewable resources – a natural resource

that is not replaced as it is used)

o Using cleaner resources (renewable resources – a resource that is naturally

replaced in a relatively short time, for example solar energy)

o Protection of habitats and endangered species

o Use of biological controls instead of pesticides and herbicides

o Farming native plants

o Planting trees to replace those cut down

o Rotating crops or planting cover crops to reduce soil loss