Unit 5 ECOLOGY

Introduction to ecology Chapter 18 Introduction to ecology

Section 1 Introduction to ecology

Section 1

Introduction to ecology Study of the interactions between ____________________________________________________________________________________________________________ Organisms depend on each other Broad science seeking to explain __________________________________

Interdependence: a key theme in ecology In the past, human survival depended on ____________________________________ Even today humans interact with the environment and other organisms daily

Organisms and their environments All orgs interact with other orgs and nonliving portion of environment Survival depends on these interactions This is called _________________________ ______________________________ Example: ____________________________ ____________________________________

Effects of interdependence Any change in environment can spread through the network of interactions

Ecological models Ecology is complex and difficult to study ________________represent and describe components of an ecological system Helps us understand environmental interactions and _____________________ ___________________________________ Helps _______________________________ ____________________________________ Not always accurate due to too many variables

Levels of organization Hierarchy of organization

The biosphere Broadest, _____________________level ________________________________ All orgs are in the biosphere _______________________________

ecosystems _____________________________________________________________________

Communities, populations, and organisms Community: _________________________ (excluding nonliving factors) Ecologists study interactions, very complex Population: _________________________ ___________________________________ Organism: individual Research focuses on __________

Communities, populations, and organisms

Homework section 1

Section 2 ecology of organisms

Section 2

Ecology of organisms Habitat: _____________________________ _______________________________________________________________________

Ecosystem components Two types of environmental factors that influence an org: Biotic: ______________________________ Abiotic: ________________________________ ____________________________________________________________________________

Biotic and abiotic factors Importance of each factor varies between environments Not constant Example: ___________________ __________________________________________________________________________________

Organisms in a changing environment Organisms can survive in a _____________ _____________________________________ Example: can survive in limited range of temperatures Determine this range by measuring ________________________________ Graph of performance vs environmental variable = _____________________________

Organisms in a changing environment Organism can survive outside optimum range, but performance is _____________ Cannot survive outside tolerance limits Optimum: ___________________________ Tolerance: ___________________________

acclimation __________________________________________________ Only some spp can do this Not to be confused with adaptation. ____________________________________________________________________________________________________

Control of internal conditions Abiotic factors fluctuate (__________________________________) Two ways orgs deal with this Conformers: ____________________________ ____________________(cold blooded animals) Regulators: ___________________________ _______________________________________(mammals and birds)

Escape from unsuitable conditions Survival by escaping temporarily _________________________________ ____________________________________ ___________________________________

The niche A niche refers to ______________________ ________________________________________________________________________ Includes range of conditions org can tolerate, resources, methods to obtain resources, number of offspring, time of reproduction Generalist: __________________________ ___________________________________ Specialist: __________________________ ___________________________________

Homework section 2

Section 3 energy transfer

Section 3

Energy transfer All orgs need energy to carry out essential functions In ecosystem, ________________________ ____________________________________________________________________________________________________________

producers Autotrophs ___________________________ Most are photosynthetic, _________________ Some bacteria uses chemosynthesis: ____________________________________________________________________________ In terrestrial ecosystems, _________________ _____________________________________ In aquatic ecosystems, ___________________ ___________________________________________________________________________

Measuring productivity Gross primary productivity: ______________ ________________________________________________________________________ Biomass: ____________________________ ____________________________________ Only energy stored in biomass is available for other orgs Net primary productivity: _______________ ____________________________________ _______________________________________

Measuring productivity Light, temp, precipitation accounts for most variation in productivity

consumers Heterotrophs: __________________________ ____________________________________________________________________________ Obtain energy by _______________________ ___________________________________________________________________________

consumers Grouped according to type of food eaten: Herbivores _______________________ Carnivores ____________________________ Omnivores _____________________________ Detritivores feed on ______________________ ______________________________________ Some detritivores are decomposers, _____________ ______________________________________________________________________________________

consumers

Energy flow When one org eats another, _____________ ___________________________________ Energy flows through an ecosystem from ________________________________ Trophic levels indicate the orgs position in a sequence of energy transfers All ______________in first trophic level ____________________ in second trophic level _______________belong to third trophic level Terrestrial ecosystems have 3 or 4 levels, marine ecosystems have more

Food chains and food webs

Food chains and food webs Feeding relationships are more complicated than just one chain. ________________________________________________ Food chains interlink Food web: ___________________________________________________________________________

Energy transfer Low % of energy transfer from one trophic level to the next, why? _____________________________________ ______________________________________

Energy transfer

Limitations of trophic levels Low rate of energy transfer is why only a few levels exist ________________________________________________________________________ ____________________________________

Homework section 3

Section 4 ecosystem recycling

Section 3

Ecosystem recycling Matter must be recycled and reused _________________________________________________________________________________________________________________________________________

The water cycle Cells contain 70-90% water Environment for chemical reactions Very little of water on Earth is available for use Water can be found in: ____________________________________ _____________________________________

The water cycle

The water cycle Important processes Evaporation: ____________________________ ______________________________________________________________________________ Transpiration: ___________________________ ______________________________________________________________________________ Precipitation: ____________________________ _______________________________________

The carbon cycle Photosynthesis: ______________________ ____________________________________ Cellular respiration: ____________________ ____________________________________ By-products are CO2 and H2O Decomposers ________________________ ____________________________________

The carbon cycle

Human influence on the carbon cycle [CO2] in atmosphere has risen over 30% Humans burn fossil fuels and other organic matter Fossil fuels: __________________________ ____________________________________ Deforestation causes __________________ ___________________________________

Nitrogen cycle ____________________________________ N2 (_____) makes up 78% of atmosphere ______________________________________ Converting N2 to nitrate = _________________

Nitrogen cycle Nitrogen fixing: _______________________________________ ______________________________________

Nitrogen cycle

Recycling nitrogen Dead bodies of orgs, urine and dung contain N Decomposers break down these materials and release N as ammonia NH3 = _____________ Soil bacteria oxidizes this into nitrate = ________________ Erosion of rocks release _________________ N is returned to atmosphere through ______________________

Recycling nitrogen Denitrification: ________________________ ____________________________________ Plants absorb nitrates from soil, animals cannot ________________________________________________________________________

Phosphorous cycle Essential element to form _______________ Plants get P from ____________________ Animals get P by _____________________ P cycle: _____________________________ ____________________________________ Slow cycle

Phosphorous cycle Rocks erode, _________________________ ____________________________________ Plants absorb P through ___________ P added to soil through ________________ ___________________________________ Fertilizer adds P to soil, ________________ _________________________________

Phosphorous cycle

Homework section 4