AP Prep Ecology Unit

• Do Now: If you could travel to any natural environment, where would it be and why?

•34.1 Ecologists study how organisms interact with their environment at several levels

– Organism• Individual organisms interacting with the environment

– Population• Group of individuals of the same species living in a

particular geographic area

– Community• All the populations of different species that inhabit a

particular area

– Ecosystem• All the biotic and abiotic components in a certain

area

– Ecological research is conducted in the field as well as in the lab and with models

THE BIOSPHERE

•34.2 The biosphere is the total of all of Earth's ecosystems

– The biosphere is the global ecosystem• Atmosphere to an altitude of several kilometers• Land down to 3,000 m beneath Earth's surface• Oceans to a depth of several kilometers

– The biosphere is self-contained and characterized by patchiness

CONNECTION

•34.3 Environmental problems reveal the limits of the biosphere

– No part of the biosphere is untouched by human activities

– Current awareness of the biosphere's limits stems from past environmental practices

• Rachel Carson warned of the effects of pesticides in 1962

Biotic vs. Abiotic

• Abiotic factors: nonliving parts of the environment– Air, temperature, moisture, light, soil

• Biotic factors: living organisms in the environment– Producers: Organisms that take in energy from their

surroundings to make their own food (Plants and some bacteria)

– Consumers: Organisms that eat (consume) other organisms for energy (animals)

– Decomposers: Consumers that eat waste products for energy. Waste products are feces, urine, fallen leaves, dead animals. (Fungi, some bacteria)

•34.4 Physical and chemical factors influence life in the biosphere

– Major abiotic factors determine the biosphere's structure and dynamics

• Solar energy• Water• Temperature• Wind• Disturbances such as fire, hurricanes

Ecology studies the relationship of organisms and their environment on several levels

• Organism• Population: group of organisms, all of the same species, which interbreed and live in the

same area at the same time– Organisms may compete with each other for resources such as food, water, space, mates, etc.

• Community: group of populations that live in the same area at the same time

– A change in one population can cause a change in another population

Ecosystem: a biological community and the nonliving things in the community’s environment

– Terrestrial ecosystem: located on land– Aquatic ecosystem: located in water

• Biome: Similar ecosystems: Rainforest, Desert, Deciduous forest etc.• Biosphere: portion of the Earth that supports living things

– Air, land, fresh water, salt water

Habitat vs. Niche

• Habitat: the place where an organism lives out its life• Niche: all the strategies and adaptations a species uses in its

environment– Includes all its interactions with the biotic and abiotic parts of the

environment– Each type of organism occupies its own niche to avoid competition

with other types of organisms• Two species can share the same habitat but not the same niche

– Example: Ants and bacteria both live in the dirt (habitat) but have different niches. Ants eat dead insects and bacteria eat dead leaves, dead logs, and animal waste. So ants and bacteria don’t compete for resources.

•34.5 Organisms are adapted to abiotic and biotic factors by natural selection

– Species exist in a given place because they evolve there or disperse there

– Unique adaptations that fit a particular environment allow organisms to survive there

• Example: pronghorns

– Organisms vary greatly in their ability to tolerate fluctuations and long-term changes in their environment

Survival relationships

• Predator-prey: predators are consumers that hunt and eat other organisms called prey

• Symbiosis: relationship in which one species lives on, in, or near another species and affects its survival– There are 3 types of symbiosis

• Mutualism• Commensalism• Parasitism

Mutualism:

• Mutualism: type of symbiosis in which both species benefit

• Ants living in the tropical acacia trees- trees are protected when ants attack animals that try to feed on the tree and ants receive nectar and shelter from the tree.

Commensalism:

• Commensalism: type of symbiosis in which one species benefits and the other species is neither harmed nor benefited– Spanish moss grows on the branches of trees. The

moss gets a habitat and the tree gets nothing.

Parasitism

• Parasitism: type of symbiosis in which one species benefits and the other species is harmed– Parasite: organism that harms but does not kill

another organism– Host: organism that is harmed by a parasite– Ticks feed on dogs, people, etc. The ticks get food

(blood) and the hosts lose blood and can be infected with disease.

36.3 Predation leads to diverse adaptations in both predator and prey

• Predation is an interaction between species in which predator kills and eats prey

• Adaptations of both tend to be refined through natural selection

– Camouflage – Chemical defense

Video: Seahorse Camouflage

– Batesian mimicry• Palatable species mimics an unpalatable model

– Mullerian mimicry• Two unpalatable species mimic each other

LE 37-5

Eggs

Sugardeposits

36.9 Trophic structure is a key factor in community dynamics

• Trophic structure: a pattern of feeding relationships consisting of several different levels

• Food chain: sequence of food transfer up the trophic levels

– Moves chemical nutrients and energy

• Producers– Autotrophs that support all other trophic levels– Plants on land– In water, mainly photosynthetic protists and

cyanobacteria (algea and aquatic plants also important)

• Primary consumers– Herbivores that eat plants, algae, or phytoplankton

• Secondary, tertiary, and quaternary consumers – Eat consumers from the level below them

• Detritivores (decomposers)– Animal scavengers, fungi, and prokaryotes– Derive energy from detritus produced at all trophic

levels– Decomposition is essential for recycling nutrients in

ecosystems

Video: Shark Eating Seal

LE 37-9Trophic level

Quaternaryconsumers

Tertiaryconsumers

Hawk

Snake

Mouse

Grasshopper

Plant

A terrestrial food chain An aquatic food chain

Producers

Primaryconsumers

Secondaryconsumers

Phytoplankton

Zooplankton

Herring

Tuna

Killer whale

36.10 Food chains interconnect, forming food webs

• A food web is a more realistic view of trophic structure

– Consumers usually eat more than one type of food – Each food type is consumed by more than one type

of consumer

LE 37-10Quaternary,

tertiary,

and secondaryconsumers

Tertiaryand

secondaryconsumers

Secondaryand

primaryconsumers

Primaryconsumers

Producers(plants)

36.11 Energy supply limits the length of food chains

• Primary production: amount of solar energy converted by producers to chemical energy in biomass

– Biomass: amount of organic material in an ecosystem

– Net primary production: amount of biomass produced minus amount used by producers in cellular respiration

– Varies greatly among ecosystems

Only about 10% of the energy stored at each trophic level is available to the next level

– Pyramid of production shows loss of energy from producers to higher trophic levels

– Amount of energy available to top-level consumers is relatively small

• Most food chains have only three to five levels

LE 37-13

Tertiaryconsumers

Secondaryconsumers

Primaryconsumers

Producers

10 kcal

100 kcal

1,000 kcal

10,000 kcal

1,000,000 kcal of sunlight

Water Cycle

• Draw a picture of the water cycle:– First write the ways the that water cycles– Draw it underneath

• Draw a picture of the carbon cycle– First write all the ways that carbon moves through

a ecosystem– Draw a picture of this

• Water Cycle • Into the atmosphere:

– Evaporation: off of water and land– Transpiration: water evaporating from the stomates on the bottom of leaves (stomates are holes that

open and close to regulate water in plants)– Water in the air

• Condensation: creates clouds

• On land– Run off : water flowing down mountains– Seepage: water absorbed into ground water– Root uptake

• Out of the atmosphere:– Precipitation:

• Carbon Cycle• Add Carbon Dioxide:

– Combustion: burning fossil fuels and fires– Respiration of plants, animals and decomposers:

oxygen + Glucose = Carbon dioxide and water– Volcanoes

• Subtract Carbon Dioxide:– Photosynthesis from green plants: Carbon dioxide + Water= Glucose + oxygen– Can be dissolved into water

Nitrogen Cycle

Nitrogen Cycle (more complex)

• Free Nitrogen:N2 is in the air (80% of all nitrogen)– Nitrogen fixing bacteria turn the free nitrogen into nitrates

(NO3)• Nitrates are absorbed by plants • Plants are eaten by animals• This is how we get nitrogen for our proteins

• Dead organisms decay into Ammonia• Ammonia (Two routes back into the cycle

– Nitrifying bacteria turns it into Nitrites (NO2) then to Nitrates– OR– Denitrifying bacteria turns ammonia into free nitrogen (N2)

Phosphorus Cycle

• All organisms require phosphorus for growth and development– Plants from the soil– Animals from food

• Short Term• Organisms decompose into soil

• Long Term– Phos washed into sea, and

incorporated into rocks– Rocks become exposed and

weathered

Succession

• Ecological Succession:– A series of changes by which one habitat changes

into another• 1) Pioneer species arrive (lichen and algae)• 2) Through natural processes, the pioneer species make

the area suitable for other organism• 3) Finally, after a long period of time, it becomes a stable

environment called a Climax Community

– Two patterns• Bare rock - forest • Lake - forest

Two types of Succession

• Primary Succession:– No soil (rock)-- climax community

• Secondary Succession:– Disturbance in existing environment– Fire, clearing, ect.– One ecosystem to another ecosystem

Diagram 1: Primary successionRock to Climax Forest

Primary Succession 2:Diagram: Lake to Climax Forest

Open Water Lake

Accumulation of Sediment

Climax Community

Causes of succession

• Climate changes, natural disasters, and human activity

Conclusion

• Biodiversity increases stability

Secondary Succession