Semester 1: Unit 3ECOLOGY

• Ecology- scientific study of interactions among & between organisms & their physical environment.

3.1- What is Ecology?

• Ecology studies levels of organization:

*Specie- Individual organism

*Population- group of the same type of individuals that live in the same area

*Community- groups of different populations living together in a defined area

*Ecosystem- all the organisms that live together in a place with their physical environment

*Biome- a group of ecosystems that share similar climates & typical organisms

*Biosphere- entire planet

3.1- What is Ecology?

•biotic factors- biological influences on organisms (living factors)

• Examples of biological influences on a bullfrog- algae it eats as a tadpole, herons that eat bullfrogs, & other species competing for food or space.

3.1- What is Ecology?

• Abiotic factors- physical components of an ecosystem (nonliving factors)

• a bullfrog could be affected by abiotic factors such as water availability, temperature, & humidity.

3.1- What is Ecology?

• abiotic & biotic factors- not always clear

• Ex: pond muck contains nonliving particles, mold, & decomposing plant material that is food for bacteria & fungi

4.1- Climate

• Weather - day-to-day conditions of Earth’s atmosphere

• Climate- year-after-year patterns of temperature & precipitation.

• main force in climate= solar energy from sun• Some energy absorbed & converted into heat

• Some heat is trapped in the biosphere & determines average temperature

4.1- Climate

4.1- Climate• Earth’s temp controlled by 3 atmospheric gases- CO2,

methane, & water vapor

• “greenhouse gases”- allow light to enter but trap heat- the greenhouse effect

• Greenhouse gas concentrations rise, more heat trapped= Earth warms.

• Without greenhouse effect, Earth would be 30°C cooler than it is today.

4.1- Climate

4.2- Niches & Community Interactions

• Each species has its own tolerance- ability to survive & reproduce under a range of environmental circumstances.

• Cannot survive past upper & lower limits

4.2- Niches & Community Interactions

• Habitat- place an organism lives. (address)• Niche- conditions in which a species lives &

how it obtains what it needs to survive & reproduce. (job)

• resource - necessity of life- water, nutrients, light, food, mates, space

• Competition- organisms try to use the same limited resource in same place at same time

• competitive exclusion principle- no 2 species can occupy exactly the same niche in the same habitat at the same time

4.2- Niches & Community Interactions

Showing different species

in different niches in

same habitat

Competition:

winner? Loser?

4.2- Niches & Community Interactions• Predation- one animal (predator) captures &

feeds on another (prey)

• symbiosis- relationship in which 2 species live closely together

3 types of symbiotic relationships:• mutualism- both species benefit• parasitism- 1 organism lives in/on another &

harms it• commensalism- 1 organism benefits & other is

not helped or harmed

4.3- Succession

• Ecological succession- series of predictable changes that occurs in a community over time

1-primary succession- begins in areas with no soil or life (ex- volcanic explosion)

• pioneer species- 1st to colonize barren areas

4.3- Succession2-secondary succession- begins where soil remains

• rebuilds faster than primaryex-wildfire, hurricane, natural disturbance, or

human activities- logging & farming.

4.4- Biomes• Biomes- consist of

abiotic & biotic factors

• seasonal patterns

of temp & precipitation

in a- climate diagram

• Temp- line graph

• Precipitation- bar graph

5.1- How Populations GrowExponential Growth:

• Ideal conditions & unlimited resources, population grows exponentially

• the larger a population, faster it grows

• on a graph over time, a J-shaped curve

5.1- How Populations Grow

Logistic Growth:

• a population’s growth slows & then stops, following exponential growth.

• Natural populations do not grow long exponentially; something stops growth

• On a graph, curve has an S-shape

5.1- How Populations Grow• Carrying capacity- maximum # of individuals that a

particular environment can support.

• Where dotted line intersects the y-axis = carrying capacity.

5.2- Limits to Growth

• limiting factor- factor that controls the growth of a population

1. Density-dependent limiting factors -operate strongly when population density is large.

• D-D L F: competition, predation, herbivory, parasitism, disease, stress from overcrowding

Competition:

• populations become crowded, individuals compete-food, water, space, sunlight, etc.

• lower birthrates, increased death rates

5.2- Limits to Growth

Predation:

predator population affects prey population & vice-versa

Herbivore Effects:

To plants, herbivores are predators

5.2- Limits to Growth

Parasitism and Disease:

• Parasites & disease-causing organisms feed & harm hosts- weaken, cause disease, or death

• more dense host population, easier to spread

Stress From Overcrowding:

• species fight if overcrowded; increase stress & weaken body’s ability to resist disease

• Females neglect, kill, or eat own offspring

• decrease births, increase deaths, & increase emigration

5.2- Limits to Growth2- Density-Independent limiting factors- affect all

populations regardless of size & density

• D-I L F include: Unusual weather- hurricanes, droughts, floods, & natural disasters- wildfires

6.1- A Changing Landscape

• Sustainable development- provides for human needs & preserves ecosystems that produce natural resources.

• Goods- items that can be bought & sold

• Services- processes or actions that produce goods.

• ecosystem goods & services- produced by ecosystems that benefit human economy.

• Healthy ecosystems provide goods & services naturally & free of charge: air, water

6.2 Using Resources Wisely

Biological magnification- a

pollutant is picked up by

an organism & is not broken

down or eliminated from

its body.

• pollutant collects in body tissues &

build as it moves up

trophic levels

6.3 Biodiversity

• Biodiversity- total of all the genetically based variation in all organisms in biosphere.

• Ecosystem diversity- variety of habitats, communities, & ecological processes in the biosphere

• species diversity- number of different species in the biosphere or particular area

• Genetic diversity- sum total of all different forms of genetic information carried by a particular species, or all organisms on Earth.

6.3 Biodiversity• Humans reduce biodiversity by:

*altering natural habitats *hunting *introducing invasive/exotic species *releasing pollution into food webs*contributing to climate change

• To conserve biodiversity, we must protect species, preserve habitats & ecosystems

• ecological hot spot- place where large numbers of species & habitats are in immediate danger of extinction.

6.3 Biodiversity

• Development splits ecosystems into pieces- habitat fragmentation- leaving habitat “islands” - patch of habitat surrounded by a different habitat.

6.4 Meeting Ecological Challenges• ecological footprint- total area of functioning land &

water ecosystems needed to provide the resources an individual or population uses & to absorb the wastes that it generates.

6.4 Meeting Ecological Challenges

• Ecology can guide humans toward a sustainable future & have a positive impact on the global environment by:

(1) recognizing a problem in the environment

(2) researching the problem to determine its cause

(3) using scientific understanding to change our behavior