Ecology Notes

What is ECOLOGY?

Ecology is a study of connections in nature. How organisms

interact with one another and with their nonliving environment.

Figure 3-2

Levels of Organization

Organisms The different forms of life on earth

Species Organisms that can breed & produce fertile offspring

Population A group of individual organisms

that belong to the same species and live in the same area.

Community Different populations that live &

interact in an area.

                                                

Ecosystem The community plus their non-living

environment.

Biotic & Abiotic Factors of Ecosystems Biotic (living)

Ex. – bacteria, animals, plants Abiotic (non-living)

Ex. – humidity, solar energy, rocks, clouds

Biome A group of ecosystems that have the same

climate Ex. – Tundra, Taiga, Desert, Tropical Rainforest

Biosphere All of the

combined portions of the planet where life exists, including land, water, and atmosphere

Fig. 3-2, p. 51

Communities

Subatomic Particles

Atoms

Molecules

Protoplasm

Cells

Tissues

Organs

Organ systems

Organisms

Populations

Populations

Communities

Ecosystems

Biosphere

Earth

Planets

Solar systems

Galaxies

Universe

Organisms

Realm of ecology

Ecosystems

Biosphere

Energy Flow Producers Autotrophs - use solar energy or

chemical energy to make their own food

                                  

Photosynthesis

Chemosynthesis

Energy Flow ConsumersHeterotrophs - get energy from the food

they eat

Herbivores – eats plants

Carnivores – eats animals (includes insects)

Omnivores – eats plants and animals

Detritovores – feed on dead matter (scavengers)

Decomposers – break down dead matter

Break it Down Auto – self

Troph – feeding

Photo – light

Synthesis – make

Hetero – different

-vore – eat

Herb – plant

Carni – meat

Omni – all

Energy Flow Food Chains & Food Webs

Show how energy & nutrients move from one organism to another through the ecosystem

Energy Pyramid Shows the amount of energy available at

each trophic level

100%

10%

1%

0.1%

Primary Consumer

Secondary Consumer

Tertiary Consumer

Producer

Energy Flow Losing Energy in Food Chains and Webs

90% of the energy at each energy level is lost because the organism uses the energy. (heat)

Biomass pyramid – total amount of living tissue- Amount of potential food for each trophic level

Pyramid of Numbers – # of individuals at each level- Does not always resemble a pyramid- Forest – fewer producers than consumers

1 tree = lots of insects / birds

Energy Flow Other Pyramids

Interactions in an Ecosystem Habitat – The area where an

organism or a population lives

Niche - the total role of a species in an ecosystem All the physical and biological conditions a

species needs to live & reproduce in an ecosystem

Interactions in an Ecosystem

Predation – one organism captures and feeds on another

Interactions in an Ecosystem Relationships

Predator – Prey Cycle

SOURCE: Isle Royale Wolf/Moose Study | GRAPHIC: By Patterson Clark, The Washington Post - July 21, 2008

Interactions in an Ecosystem Relationships

Competition – organisms of the same or different species attempt to use the same resources at the same time

Interactions in an Ecosystem Relationships Symbiosis – any relationship in which 2

species live closely together

Mutualism Commensalism Parasitism

Mutualism: Win-Win Relationship Both of them benefit

Pollination of flowers by insects Oxpeckers and black rhinoceros

Commensalism: Using without harming One is helped and has little or no effect on

the other

Burrs are carried by animals. This helps scatter the seeds for the parent plant.

Parasitism: Sponging Off of Others One benefits and the other is harmed

MosquitosTapeworms

Carrying Capacity The maximum # of individuals

that a given habitat can support

What is the carrying capacity?

Fig. 3-11, p. 58

Zone of intolerance

Optimum rangeZone of physiological

stress

Zone of physiological

stress

Zone of intolerance

TemperatureLow High

Noorganisms

Feworganisms

Upper limit of tolerance

Po

pu

lati

on

siz

e

Abundance of organismsFew organisms

Noorganisms

Lower limit of tolerance

4 Factors Determine Growth Rate1. Birth rate2. Immigration3. Death rate4. Emigration

Which increase and which decrease the population?

Limiting FactorsBiotic or abiotic resource that

limits size of population

Habitat Needs Cover – shelter; trees, shrubs,

etc. Water Nutrients

Populations can grow until competition for resources increases & the carrying capacity is reached

Population Growth

Fig. 3-7, p. 55

Nitrogencycle

Biosphere

Heat in the environment

Heat Heat Heat

Phosphoruscycle

Carboncycle

Oxygencycle

Watercycle

CARBON CYCLE

Nitrogen Cycle

Nitrogen Fixation This is the first step of the nitrogen cycle

where specialized bacteria convert gaseous nitrogen to ammonia that can be used by plants. This is done by cyanobacteria or bacteria living in the nodules on the root of various plants.

Nitrification Ammonia is converted to nitrite, then to

nitrate

Plant roots absorb ammonium ions and nitrate ions for use in making molecules such as DNA, amino acids and proteins.

Assimilation

Ammonification After nitrogen has served its purpose in

living organisms, decomposing bacteria convert the nitrogen-rich compounds, wastes, and dead bodies into simpler compounds such as ammonia. Denitrification

•Nitrate ions and nitrite ions are converted into nitrous oxide gas and nitrogen gas.

This happens when a soil nutrient is reduced and released into the atmosphere as a gas.

BiomagnificationConcentration

of toxin at higher trophic levels

Succession The process where plants & animals

of a particular area are replaced by other more complex species over time.

Stages of Succession

Land – rock lichen small shrubs large shrubs small trees large trees

Primary Succession When the starting

point is an ABIOTIC environment

VolcanoFlood

Secondary Succession

When an EXISTING ecosystem is disturbed

Fire/lightningDiseaseHurricanesHuman activities

Credit: Jeff Schmaltz, NASA's MODIS Rapid Response Team

Wetland Succession

© 2003 John Wiley and Sons Publishers

Fig 10.7 Diagram of bog succession.

Wetland Succession

Sedges and floating

plants close over the open

water, trapping

sediments in their roots,

and gradually drying out the

pond.

1

2

3

CLIMATE: A BRIEF INTRO.

Weather - local, short-term conditions such as temperature and precipitation

Climate - a region’s average weather conditions over a long time Latitude and elevation help determine climate

BIOMES:

Large terrestrial regions characterized by similar climate, soil, plants, and animals

Biomes Around the World

DESERT BIOMES The evaporation is greater than the

precipitation (usually less than 25 cm). Covers 30% of the earth.

DESERT BIOMES

Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts.

Figure 5-12

FOREST BIOMES

Forests have enough precipitation to support stands of trees and are found in tropical, temperate, and polar regions.

FOREST BIOMES

Variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar forests.

Figure 5-19

Taiga (evergreen coniferous forest) Just south of the tundra (northern part of N.

America), it covers 11% of earth’s land. Its winters are long, dry & cold. Some places have sunlight 6 to 8 hours a day. The summers are short and mild, w/ sunlight 19 hours a day.

MOUNTAIN BIOMES (Taiga) High-elevation

islands of biodiversity

Often have snow-covered peaks that reflect solar radiation and gradually release water to lower-elevation streams and ecosystems.

Evergreen Coniferous Forests

Consist mostly of cone-bearing evergreen trees that keep their needles year-round to help the trees survive long and cold winters.

Tropical Rainforest Near the equator. It has warm

temperatures, high humidity & heavy rainfall.

Tropical Rain Forest Tropical rain

forests have heavy rainfall and a rich diversity of species. Found near the

equator. Have year-round

uniformity warm temperatures and high humidity.

Tropical Rain Forest

Filling such niches enables species to avoid or minimize competition and coexist

Temperate Rain Forests

Coastal areas support huge cone-bearing evergreen trees such as redwoods and Douglas fir in a cool moist environment.

Temperate Deciduous Forest It has moderate temperatures, long, warm

summers, cold winters &lots of rain. Trees include oaks, hickory, maple, and beech.

Temperate Deciduous Forest

Most of the trees survive winter by dropping their leaves, which decay and produce a nutrient-rich soil.

Grassland The rainfall is erratic & fires are

common. It has & shrubs that are good for grazing animals.

GRASSLANDS AND CHAPARRAL BIOMES

Variations in annual temperature (red) and precipitation (blue).

Figure 5-14

Savanna The tropical & subtropical grassland.

It is warm all year long with alternating wet & dry seasons.

Chaparral (temperate grassland) These are coastal areas. Winters are mild

& wet, w/ summers being long, hot, & dry.

Chaparral

Chaparral has a moderate climate but its dense thickets of spiny shrubs are subject to periodic fires.

Temperate Grasslands

The cold winters and hot dry summers have deep and fertile soil that make them ideal for growing crops and grazing cattle.

Tundra (polar grasslands) Covers 10% of earth’s land. Most of the year,

these treeless plains are bitterly cold with ice & snow. It has a 6 to 8 week summer w/ sunlight nearly 24 hours a day.

                                           

Polar Grasslands

Polar grasslands are covered with ice and snow except during a brief summer.