Ecology Environmental Interactions

What is ecology?

• “Eco”= environment, house

• “Ology”= study of

• Ecology- the scientific study of interactions

among organisms and their environment or

surroundings

• The study of ecology looks primarily at the

biosphere, or area where all life exists.

• “Bio”= Life

• “Sphere”= circle, zone

How do we organize and group

life?

• A species is a group of organisms so

similar to one another that they can

breed and produce fertile offspring

• A species is the most specific grouping

of life

• Example= grey wolf

• All the wolves that live in one area

would be called a population, or group

of individuals that belong to the same

species and live in the same area.

• If we wanted to look at all the

different populations that live

in an area, we would be

looking at a community, or the

assemblage of different

populations that live together

in a defined area.

• Keep in mind that a

community only involves the

living, or biotic factors!!

Ex. All the animals and plants in a

forest

Bringing it all together…

• The next level of

organization is the

ecosystem.

- In an ecosystem, we

study a collection of all

the living organisms that

live in a particular place

together with their

nonliving, or abiotic,

environment.

Ex. Forests

The final step…

• The final and largest level of

organization (excluding the biosphere),

is the biome.

• Biomes are groups of ecosystems that

have the same climate and similar

dominant communities…

Biomes of the World…

• Tropical Rainforest

• Tropical Dry Forest

• Tropical Savanna

• Temperate Grassland

• Desert

• Temperate woodland and scrublands

• Temperate Forest

• Northwestern coniferous forest

• Boreal Forest (Tiaga)

• Tundra

• Mountains and Ice Caps

• Bodies of Water

What makes them unique and

different from one another?

• Location around the globe

• Climate

• Dominant plant and animal species

Tropical Rainforest

– Climate: hot, wet

– Soil: thin, poor

– biodiversity: high

Tropical Dry Forest

– Climate: warm, alternating wet and dry

– Soil: rich

– biodiversity: average

Tropical Savanna

– Climate: warm, seasonal rainfall

– Soil: compact

– biodiversity: average

Deserts

– Climate: variable temps., low rainfall

– Soil: rich in minerals, poor in organics

– biodiversity: average to low

Temperate Grasslands

– Climate: warm summers and cold winters,

moderate precipitation

– Soil: fertile

– biodiversity: average

Temperate Woodland and

shrubland

– Climate: warm, dry summers and cold,

moist winters

– Soil: thin, poor

– biodiversity: average

Temperate Forest

– Climate: warm summers and cold winters,

year round precipitation

– Soil: fertile

– biodiversity: average

Northwestern Coniferous Forest

– Climate: mild temperatures, abundant

precipitation fall, winter, and spring

– Soil: rocky, acidic

– biodiversity: average

Boreal Forest

– Climate: mild summers and long, cold

winters, moderate precipitation

– Soil: acidic, poor

– biodiversity: average

Tundra

– Climate: short, soggy summers and long,

dark, cold winters, low precipitation

– Soil: poorly developed, permafrost

– biodiversity: low

And the rest…

• Mountains

• Ice Caps

• Aquatic Biomes

– Oceans

– Lakes

– Rivers

– Ponds

– Etc.

Let’s go to the video…

• Biomes

Energy Flow Through an

Ecosystem

Ways of acquiring energy

• Autotrophs- can make their own

energy by converting the energy of the

sun into food. These organisms are

also called producers.

Acquiring Energy Con’d

• Heterotrophs- Organisms that get

their energy by consuming other

organisms. Also known as

consumers.

Can an organism be both???

• YES!!!

– Venus flytrap

– sun dew

– Pitcher plant

One more way to “power up”

• Chemotrophs are able to combine

different chemical compound (without

light) to make power. This process is

called chemosynthesis.

How they all interact…

• When an organism obtains energy by

eating only plants, it is called a

herbivore…

• If they eat only meat, they are

carnivores…

• Eating plants and meat make an

organism an omnivore…

Bottom Feeders…

• Detritivores feed on the remains of

plants and animals along with other

dead material called detritus.

• This includes worms, snails, mites,

and….

crabs

“Stinky dead animals,” brought

to you by…

• Decomposers- break down organic

matter

• Examples: bacteria, fungus

Putting them all together…

• Feeding relationships are shown using

two different graphs, food chains and

food webs.

– Food chains show a series of steps in

which organisms transfer energy by

eating and being eaten.

Webs…

• Food webs are a network of complex

interactions that show feeding

relationships.

– Webs are better at showing actual

interactions on a large scale

The levels of organization

• Each step in a food chain is called a

trophic level.

• They go as follows: Top level carnivores

1st level carnivores

herbivores

producers

Trophic levels

Trophic levels con’d

• Available energy at each level is

shown on an ecological pyramid.

• Numbers represent percentage of

original sunlight energy still available

for use…

• Available energy: – Producers= 100%

– Herbivores (primary consumers)= 10%

– 1st level carnivores (2ndary consumers)= 1%

– 2nd level carnivores (tertiary consumers)= .1%

Ecological pyramid

Community Interactions

A few terms…

• Biotic factors- biological (living)

influences on organisms within an

ecosystem • Ex. Trees, birds, people, etc.

• Abiotic factors- physical, or nonliving,

factors that shape ecosystems • Ex. Rivers, wind, soil, temperature, etc.

• Habitat- the area where an organism

lives

More terms…

• Niche- the full range of physical and

biological conditions in which an

organism lives and the way the

organism uses those conditions

– Baseball players – Each person on the field has a job and a specific

place to do that job, that is their “niche”

Resources

• Resources are necessities of life and

include water, nutrients, light, food and

space.

– What happens if two organisms both want

to use the same resources??

Resources

• This idea that no two species can

occupy the same niche in the same

habitat is called the competitive

exclusion principle.

• Though no two organisms can occupy

the same niche, they do interact in

many different ways.

Forms of interaction

• Predation- one organism captures and

feeds on another

• Symbiosis- any relationship where

two organisms live closely together

– Forms of symbiosis:

• Mutualism

• Commensalism

• Parasitism

Mutualism (+/+)

• This type of symbiosis provides a

benefit for both organisms involved

– Ex. Bees and flowers, hummingbird and

flowers, etc.

Commensalism (+/neutral)

• This type of symbiosis provides a

benefit for one organism involved but

doesn’t harm or help the other

organism

– Ex. Whales and barnacles, orchids and

trees, etc.

Parasitism (+/-)

• This type of symbiosis provides a

benefit for one organism involved but

harms the other organism

– Ex. Dog and flea, people and mosquitoes,

etc.

Video Time…

• symbiosis

How do populations grow?

• - Populations are constantly changing

in number. A few ways this happens

are:

– Deaths

– Births

– Immigration

– Emigration

• All of these factors control the

population density, or number of

individuals per unit of area…

• Immigration (+)- the movement of an

individual into an area. Population

increases

• Emigration (-)- the movement of an

individual out of an area. Population

decreases

• One cannot happen without the other

In what ways do populations

grow?

• If unlimited resources are available, a

population will grow at an exponential

rate, or without limitation and at a

constant rate.

– growth starts at a low number but

increases quickly

• Example: a single bacterium lands on your

food, has offspring, who have offspring, who

have offspring and so on doubling their

numbers every 20 minutes

• a few become many...

Growth continued

• If for some reason resources do

become limited, our bacteria would

switch to a pattern of logistical growth,

or a time where a population’s growth

slows or stops after a period of

exponential growth.

– Could be caused be high death rate, low

birth rate, limited resources, etc.

Carrying Capacity

• All growth is controlled by

an imaginary number

called the carrying

capacity.

– Carrying capacity is the

maximum population

number an area can

support long term.

Ecological Succession

Changes over time…

• What is ecological succession?

– A series of predictable changes that

occurs in a community over time.

• As an ecosystem changes, older inhabitants

gradually die out and new organisms move in

causing further changes to the community

Primary Succession

• Succession that takes place where no soil

previously existed is called primary

succession.

– Soil is created through the weathering of rock

and breakdown of organic material

• May happen after a volcano or glacier

Primary succession

• The 1st species to populate this newly

created soil is called a pioneer

species.

– These species add organic material to the

nutrient poor soil as they die.

• Ex. Lichen (fungus + algae)

Secondary succession

• Succession that takes place following a

disturbance that destroys a community

without destroying the soil is called

secondary succession.

– What kind of disasters might do this??

• Floods, fires, hurricanes, tornadoes, etc.

Nutrient Cycling

Nutrients

• Nutrients are nature’s building blocks,

or all the chemical compounds that an

organism needs to sustain life.

• Essential nutrients include:

– Carbon - Iron

– Nitrogen - Zinc

– Phosphorus - Potassium

– Oxygen - Fluorine

– Hydrogen - Calcium

– Magnesium - many, many, others!!

Limited nutrients

• When an ecosystem is limited by a

single nutrient that is scarce or cycles

very slowly, that substance is called

the limiting nutrient.

– Three of the most common limiting

nutrients are:

• Nitrogen

• Potassium

• Phoshporus

– How do farmers deal with this problem??

Productivity

• Limiting nutrients along with overall

nutrient availability affect an

ecosystem’s primary productivity.

– This is the rate at which producers in the

ecosystem make organic matter

Cycling nutrients

• Matter is recycled between and within ecosystems.

What kinds of matter?

– Water

– Carbon

– Nitrogen

– phosphorus

• Biogeochemical cycles are the pathways that

elements, compounds, and other forms of matter

are passed from one organism to another or from

one area to another.

The Water Cycle

Moving H2O

• - Water is carried from the

clouds to ground through

precipitation.

• - As it moves across the

ground, some is taken back to

a gaseous form through

evaporation.

• - Plants lose small amounts of

water through transpiration.

• - As water accumulates, it

forms back into liquid water by

the process of condensation.

The Carbon Cycle

• A large percentage of carbon is found in the

atmosphere as CO2

• CO2 is collected by plants and turned into organic

tissue during the process of photosynthesis.

• This organic matter is eaten, broken down, and

given off as waste CO2 and returned to the

atmosphere

– It can also be burnt, which also gives off CO2

• When organisms die, the carbon stored in their

bodies returns to the atmosphere as CO2 as they

decay and returned to the soil as they decompose.