principles of ecology chapter 13. ecologists study relationships interactions and interdependence...
TRANSCRIPT
Principles of Ecology
Chapter 13
Ecologists Study Relationships
• Interactions and Interdependence Ecology – the
scientific study of interactions among living things and their surroundings
Ecologists Study Relationships
• Biosphere - part of a planet (the earth) in which life exists including land, water, and air
Ecologists Study Relationships
Populations – individuals that live in the same area
Species – a group of individuals that can interbreed
Ecologists Study Relationships
Communities – assemblages of different populations that live togetherCommunities are within the ecosystem
(Ex. A reef in the ocean)
Ecologists Study Relationships
Ecosystem – a collection of all organisms that live in a particular place with their nonliving, or physical environmentScientists often
study species, populations, or communities in an ecosystem.
Ecologists Study Relationships
• Levels of OrganizationBiome – a group
of ecosystems that have the same climate and similar dominant communities
Ecologists Study Relationships
• Ecological MethodsObserving – first step
Long term studies more beneficial-ecological change takes time
SurveysDirect Indirect
Determining Population Size
Catch and releaseQuadrat Sampling
Ecologists Study Relationships
Experimenting – used to test hypothesesCan do in the
field or labLab-more control,
not a true reflection
Field-More accurate, difficult to determine cause and effect relationships
Ecologists Study Relationships
Modeling – gain insightComputersMathematical
modelsUse actual
data to simulate
Data collected using satellite technology
Biotic and Abiotic Factors
• Living and Non-living components– Biotic - living
factors– Abiotic -
nonliving things
Biotic and Abiotic Factors
• Biodiversity– The assortment,
or variety of living things
– Dependent on temperature, moisture
– Keystone Species – species that have a large impact on ecosystems
Energy in Ecosystems• Producers –
organisms that make their own food Autotrophs –
organisms that use energy from the sun or chemicals to make food
Energy in EcosystemsEnergy from the
sun• Photosynthesis
– Autotrophs use light energy to power chemical reactions that make energy
– Uses CO2
– Makes O2 and Carbs
Energy in Ecosystems
Life without light• Chemosynthesis – Use chemical
energy to make carbohydrates– Bacteria deep in the ocean
Energy in Ecosystems• Consumers –
Organisms that need other organisms for their energy and food supply These are also referred
to as heterotrophs
Food Chains and Food Webs
• Feeding Relationships• Food Chains – A series of energy
transferring steps
Food Chains and Food Webs
Types of heterotrophs• Herbivores
– Energy from eating plants
• Carnivores– Energy from eating animals
• Omnivores– Both plants and animals
• Detritivores– Feed on the remains of
dead matter
• Decomposers– Break down organic matter
for energy
Food Chains and Food Webs
• Specialist– Consumer that
primarily eats one specific organism
• Generalist– Have a varying
diet
Food Chains and Food Webs
Trophic Levels – Each step in a food chain or web• First level is producers• Second level on is
consumers-usually herbivores
• Tertiary consumers are usually carnivores
• Each consumer depends on the trophic level below it
Food Chains and Food WebsFood Webs – Feeding relationships
among many organisms in an ecosystem form a network of interactions
Cycling of Matter• The Hydrological Cycle (Water
Cycle)– Evaporation – Water changes from a
liquid to a gas– Transpiration – Evaporation from the
leaves of a plant
Cycling of MatterClouds form from tiny drops of water
collecting called condensation
Cycling of Matter• Recycling in the Biosphere
Biogeochemical cycles• The transforming of matter by biological
systems
– Energy moves in a one way fashion – Nutrients recycle
Cycling of Matter• Nutrient Cycles
Nutrient – All the chemical substances that an organism needs to sustain life
Cycling of Matter• Oxygen Cycle
– Most organisms use oxygen need oxygen
– Plants release oxygen
– Living organisms release carbon dioxide as a waste product
Cycling of MatterThe Carbon Cycle
• Carbon is passed on from one situation to another throughout the biosphere
– Photosynthesis uses CO2 to make carbs
– Carbs are eaten by other organisms
– Organisms exhale CO2
during cellular respiration– All organisms eventually
decay and the carbon is converted to coal or petroleum
– Burning things releases stored CO2 into the atmosphere
Cycling of MatterThe Nitrogen Cycle
• All organisms need nitrogen to make amino acids
– What do amino acids make?– Proteins– 78% of Earth’s atmosphere
Nitrogen gas (N2)– Other types:– Ammonia (NH3)
Nitrate (NO3) Nitrite (NO2)
– Nitrogen fixation – N2 to NH3
– Denitrification - NO3 to N2
Cycling of Matter– The Phosphorus
Cycle• DNA and RNA
need phosphorus • This element does
not go into the atmosphere
• Phosphorus works its way through the food web
Cycling of Matter• Nutrient Limitation
– Ecologists look at the rate of production of producers – Primary Producivity
– Availability of nutrients can limit an ecosystem
– Limiting nutrient• Ecosystem limited by
one nutrient– Nitrogen in the ocean is the
limiting nutrient• 0.00005% nitrogen• If runoff causes a drastic
increase in nitrogen, then an algae bloom occurs
Pyramid Models• Ecological Pyramids – diagram
that shows how much energy is transferred at each trophic level
Pyramid ModelsBiomass Pyramid
• Biomass – Total amount of living tissue in a level
– Represents the amount of potential food available at each trophic level
Pyramid ModelsEnergy Pyramid
• Only about 10 % of the energy is transferred to the next trophic level
– More levels means less energy at the last level
Pyramid ModelsPyramid
NumbersShows how many
individuals there are in each level