We share the Earth…

Ecology & Environmental Issues

with a whole lot of other creatures…

We don’t share very well….

Ecology Putting it all together…

study of interactions between creatures & their environment, because…

Everything is connectedto everything else

Ecosystem Living (Biotic) factors

all plants & animals living in an area

Physical (Abiotic) factors soil, rock, temperature, moisture,

sunlight

habitat = address (where you live)niche = job (the role you play)

Creatures living in their environment

Populations

Earth’s land ecosystems

Marine

intertidal= lots of nutrients

coral reef= lots of light

benthos= deep ocean

high biodiversity

Tropical rainforest

lots of rain, lots of sunlight, always warm

many plants & animals

high biodiversity

Savannadry season/wet season, always warm

frequent fires in dry season

many herbivores

mid biodiversity

Desert

very dry, hot in day & cold at night

very few plants & only small animals:reptiles, insects, rodents, birds

low biodiversity

Temperate Grassland (Midwest U.S.)

dry season/wet season, cold winters/hot summers

frequent fires in dry season

many herbivores

mid biodiversity

Temperate Deciduous Forest

4 seasons: warm summer with rains, cold winter with snow

deciduous trees, many mammals, insects, birds, etc.

high biodiversity

Coniferous Forest (Taiga)

northern forest, drier, cooler

evergreens, mammals, birds, insects, etc.

mid biodiversity

Tundra

cold year round, dry, permafrost

only lichens & mosses & mostly migrating animals

low biodiversity

How do organisms live together? Community

populations of different species that live in the same place

Feeding relationships

Community

Community Interactions Niche Competition Predation Symbiosis

Mutualism Commensalism Parasitism

Feeding relationships all food chains

start with energy from the sun

first level of all food chains is plants

most food chainsusually go up only 4 or 5 levels

all levels connect to decomposers

Food chains

Fungi

Level 4

Level 3

Level 2

Level 1

Decomposers

Producer

Primary consumer

Secondary consumer

Tertiary consumer

Topcarnivore

Carnivore

Herbivore

Sun

Bacteria

Loss of energy Loss of energy between levels of food chain

To where is the energy lost? The cost of living!

only this energymoves on to the

next level in the food chain

17%growth

50%waste (feces)

33%cellularrespiration

energy lost todaily living

energy lost todaily living

Feeding levels How much energy

can you get from food? only the energy that is

stored in the organism

80-90% energy lost from one level to next

food chain can only have 4 or 5 levels

Food webs

Food chains are linked together into food webs

Who eats whom? eating meat? eating plants?

Many connections throughout ecosystem

Energy flows through…

sun

secondary consumers(carnivores)

primary consumers(herbivores)

producers (plants)

loss of energy

loss of energy

loss of energy

Food chain pyramid Loss of energy between levels of food chain

can feed fewer animals in each level

1,000,000,000

100,000

100

1

Numbers

Vegetarians or Meat-eaters?? How many people can Earth support?

If we are meat eaters? If we are vegetarian?

more people canlive on Earth

fewer people canlive on Earth

But what about nutrients? Energy flows through

but nutrients cycle nutrients must be

recycled to be available for the next generation

decomposers return nutrients to the soil after creatures die fungi bacteria

nutrients

decomposers

Nutrients cycle around… through decomposers

soil

producers

consumers

decomposers

potassium

nitrogen

iron

calcium

phosphorus

magnesium

carbon

2006-2007

loss of energy

loss of energy

sun

secondary consumers(carnivores)

primary consumers(herbivores)

loss of energy producers (plants)

decomposers

Nutrients cycleEnergy flows

soilsoil

biosphere

Ecosystem inputs

constant inputof energy

energy flowsthrough

nutrients cycle

nutrients can only

cycle

inputs energy nutrients

Don’t forgetthe laws of

Physics!

Matter cannotbe created or

destroyed

Beneficial Bacteria 99% of bacteria are HELPFUL not

harmful! Roles they play in the environment

Decomposer Producer Nitrogen fixation Digestion – an example of mutualism

too!!

Characteristics of Populations1. Geographic distribution

– area inhabited by a population2. Density –

-number of individuals per unit area. 3. Population growth – populations can increase or decrease in size based on 3 factors:

Number of Births Number of Deaths Individuals that enter (immigration) or leave

(emigration) a population

Exponential Growth Individuals in a population reproduce

at a constant rate Graph = J-shaped curve At first, growth is slow. Over time,

growth grows until it reaches an infinitely large size.

Occurs under ideal conditions

Logistic Growth As resources become less available,

the growth of a population slows Graph = S shaped When does this happen?

birth rate slowsdeath rate increasesimmigration decreasesemigration increases

Carrying capacity – the largest number of individuals that a given environment can support.

Limiting Factors A factor that causes population

growth to decrease 2 Types

density dependent density independent

Density Dependent Factors Factor that depends on population size Effect large populations the most

Competition – crowded organisms compete with one another for food, water, space, sunlight & other essentials.

Predation – one organism captures & feeds on another organism

Parasitism & Disease – symbiotic relationship in which one organism lives in or on another organism (the host) and consequently harms it (often causing disease or death)

60

50

40

30

20

10

01955 1960 1965 1970 1975 1980 1985 1990 1995

2000

1600

1200

800

400

0

2400

Moose Wolves

Density Independent Factors Affect all populations in similar ways,

regardless of size Unusual weather Natural disasters Seasonal cycles Some human activities

Species will often crash due to one or more of these factors. After the crash some species will recover to build up again, others remain small.

Succession Primary Succession

No pre-existing community Secondary Succession

Disruption of pre-existing community Climax community

Fully mature ecosystem Equilibrium

Any Questions??