Ecology (Chapters 3-5)
-
Upload
raquel-rii-l -
Category
Documents
-
view
236 -
download
2
Transcript of Ecology (Chapters 3-5)
![Page 1: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/1.jpg)
EcologyEcology
Chapters 3-5Chapters 3-5BiologyBiology – Miller – Miller • Levine• Levine
![Page 2: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/2.jpg)
What is Ecology?What is Ecology?
• The scientific study of:– Interactions among organisms– Interactions between organisms and their
environment• Biosphere – portions of the Earth where
life exists (land, water, and air)
![Page 3: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/3.jpg)
Levels of OrganizationLevels of Organization
• Species – group of organisms that can breed and produce fertile offspring
• Population – a group of individuals of the same species that live in the same area
• Community – different populations that live in the same area
• Ecosystem – all the organisms plus the nonliving environment
• Biome – group of ecosystems with the same climate and similar communities
![Page 4: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/4.jpg)
Levels of OrganizationLevels of Organization
![Page 5: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/5.jpg)
Energy FlowEnergy Flow
• Sunlight is the main energy source for life on Earth.
• Autotrophs (producers) – organisms that make their own food– Photosynthesis – use light energy to make
food– Chemosynthesis – use chemical energy to
make food
![Page 6: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/6.jpg)
Energy FlowEnergy Flow
• Heterotrophs (consumers) – organisms that must feed on other organisms for energy– Herbivores – eat only plants– Carnivores – eat other animals– Omnivores – eat both plants and animals– Detrivores – feed on dead matter– Decomposers – break down organic matter
![Page 7: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/7.jpg)
Feeding RelationshipsFeeding Relationships
• Energy flows through an ecosystem in one direction (sun → producers → consumers)
• Food chain – a series of steps in which organisms transfer energy by eating and being eaten
![Page 8: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/8.jpg)
Feeding Relationships Feeding Relationships • Food web – a network
of complex feeding interactions
• Trophic levels – each step in a food chain or food web– 1st – producers– 2nd – primary consumers– 3rd – secondary
consumers– 4th – tertiary consumers
![Page 9: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/9.jpg)
Ecological PyramidsEcological Pyramids
• Energy Pyramid – shows the amount of energy available at each trophic level– Only about 10% of the energy is transferred to
the next level• Biomass Pyramid – shows the amount of
living tissue within each trophic level• Pyramid of numbers – shows the number
of organisms at each trophic level
![Page 10: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/10.jpg)
Ecological PyramidsEcological Pyramids
![Page 11: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/11.jpg)
Biotic and Abiotic FactorsBiotic and Abiotic Factors
• Biotic factors – the living things that influence organisms
• Abiotic factors – the nonliving things that influence organisms– Light– Soil– Wind– Water – Temperature
![Page 12: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/12.jpg)
Habitat and NicheHabitat and Niche
• Habitat – the area where an organism lives
• Niche – the role an organism plays in its habitat– No two species can
share the same niche in the same habitat
![Page 13: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/13.jpg)
Community InteractionsCommunity Interactions
• Symbiosis – any relationship in which two species live closely together– Mutualism – both species benefit (flowers &
insects)– Commensalism – one species benefits while
the other is neither helped nor harmed (orchids in a rainforest)
– Parasitism – one organism benefits while the other is harmed (fleas on a dog)
![Page 14: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/14.jpg)
SymbiosisSymbiosis
![Page 15: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/15.jpg)
Ecological SuccessionEcological Succession
• The series of changes that occurs in a community over time
• Primary succession – occurs on surfaces where no soil exists (no previous life)– Pioneer species – the first species to
populate the area– Lichens → mosses → grasses → shrubs →
trees
![Page 16: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/16.jpg)
Primary SuccessionPrimary Succession
![Page 17: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/17.jpg)
Ecological SuccessionEcological Succession
• Secondary Succession – when a disturbance changes the existing community without removing the soil– Tornadoes, fire, clear cutting– Occurs much quicker than primary succession– Climax community – the relatively stable
final community
![Page 18: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/18.jpg)
PopulationsPopulations
• Population density – the number of individuals per unit area
• Population growth – increase in size of a population
• Population size can be affected by:– Number of births– Number of deaths– Immigration – organisms moving into an area– Emigration – organisms moving out of an area
![Page 19: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/19.jpg)
Exponential GrowthExponential Growth
• Under ideal conditions with unlimited resources, a population will grow exponentially
• J-shaped curve
![Page 20: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/20.jpg)
Logistic GrowthLogistic Growth
• As resources become less available, the growth of a population slows or stops
• S-shaped curve
![Page 21: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/21.jpg)
Limiting FactorsLimiting Factors
• A factor that causes population growth to decrease
• The population size will usually remain constant
• Creates the s-shaped curve• Two kinds of limiting factors:
– Density-dependent– Density-independent
![Page 22: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/22.jpg)
Density-Dependent FactorsDensity-Dependent Factors
• A limiting factor that depends on population size
• Competition – organisms compete for resources – Between members of the same species– Between members of different species
• Parasitism and disease
![Page 23: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/23.jpg)
Density-Dependent FactorsDensity-Dependent Factors
• Predation – when one species feeds on another– Predator – the organism that feeds on the prey– Prey – the organism being eaten
![Page 24: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/24.jpg)
Density-Independent FactorsDensity-Independent Factors
• Affects all populations, regardless of the population size
• Unusual weather – heavy storms• Natural disasters – tornado, volcanic
eruption• Seasonal cycles – insects die during winter• Human activities – clear-cutting forests
![Page 25: Ecology (Chapters 3-5)](https://reader033.fdocuments.us/reader033/viewer/2022051318/577ccd611a28ab9e788c3066/html5/thumbnails/25.jpg)
Human Population GrowthHuman Population Growth
• At first the human population grew slowly• About 500 years ago it started increasing
rapidly• Resembles the J-shaped curve
US & WorldPopulations