Terrestrial Ecosystems and Their Relationship to Cultivating Plants

Exam #2 MATERIAL (APP PL SCI)

What are terrestrial ecosystems?

collection of organisms above and within the soil

over time develop intricate relationships

share energy and resources

abiotic and biotic things living together

What is the energy source for all ecosystems?

photosynthesis

What is photosynthesis?

conversion of solar energy to chemical energy

stored in carbon-based molecules in plants

transferred from plants to other organisms

How will crop systems achieve productivity with reduce inputs?

understanding and mimicking natural systems

What is an example of a crop system?

corn (grass family = Poaceae)

Where are carbon molecules (energy) stored in?

plant’s biomass

How are ecosystems made up?

population of organisms in a physical environment

can be small or very large in area

depend on carbon fixation from photosynthesis

carbon molecules (energy) are stored in plant’s biomass (more biomass = more energy)

other organisms feed on the plants

recycle carbon and other elements

What are cultivated ecosystems?

single species of a crop interacting with many other organisms

What are within cultivated ecosystems?

other plants like weeds

large and small animals

fungi

bacteria

microflora

microfauna

What needs to be absent or modified within crop systems?

nutrients/fertilizer need to be supplied

chemicals to suppress weeds, insects, diseases

What are the 3 type of systems in cultivated ecosystems?

natural, sustainable, intensive

natural system

high soil biodiversity

low resource availability

high internal regulation

sustainable system

high soil biodiversity

sufficient resource availability

high internal regulation

What are the 6 sustainable agriculture factors in a cultivated ecosystem?

1. improved environmental health

2. minimization of offsite environmental impacts

3. reduced environmental risk

4. optimized resource usage and conservation

5. high production benefits and low cost production

6. improved food production

intensive system

high soil biodiversity

low resource availability

low internal regulation

What is a ecosystem competition?

resources in a short supply where some organisms can’t get enough

numbers of organisms are reduced or species disappears

What is a limited resource in a crowded situation of an ecosystem competition?

light

What is an example of light being a limited resource to an animal or plant?

vines and spring ephemerals are plants that have adapted to low light in woodlands

What does niche mean?

describes the place an organism has in the ecosystem

How can different niches help stop competition within ecosystems?

a species id less likely to outcompete another species if they occupy different niches

What is an example of compeition?

occurs when plants of the same or different species attempt to use a resource that is in limited supply

Natural ecosystems have organisms that transfer through what?

predation and parasitism

What is predation in natural ecosystems?

consumption by animals that eat plants and other animals than eat the herbivores to further distribute energy

Where do parasites live in natural ecosystems?

live in or on another organism, fungi, bacteria, viruses, and some plants

What can parasites do?

can cause diseases

physiology and morphology of host is altered by weakening it or being vulnerable to get attack by another organism

can be useful as biological control agents of plant pests

What does symbiosis/commensalism?

is a beneficial relationship between 2 organism

How does mycorrhiza fungi have a symbiotic relationship?

is on or within roots

extend the range of nutrient extraction for the plant

in exchange get carbon molecule energy from the plant

What does Rhizobium bacteria in roots of legumes as a symbiotic relationship?

takes in and fixes nitrogen from air

convert to form used by plants

get carbon molecule energy from plants

What are saprophytes?

mostly fungi and bacteria

microorganisms digest dead plants and animals

What are detritivores?

mostly animals

breakdown large pieces of organic matter

What is an example of a detritivore?

earthworms

What do saprophytes and detritivores do for natural ecosystems?

essential for recycling and supplying nutrients

What are biomes?

collection of ecosystems with similar climate, soil, and plant composition

Soil and climate are the main influences in creating biomes that contribute to what?

temperature and seasonal variation

precipitation and seasonal

soil type

What are the 9 different soil types in biomes?

tropical rainforest

temperate forest

boreal forest

desert

savanna

grassland

marine

freshwater

tundra

How does temperature affect and affect what is different biomes?

latitude

altitude

annual average decreases with increase in latitude

more seasonal variation with increasing latitude

annual average decreases with increase in latitude

What is precipitation in biomes?

global air circulation patterns

moisture availability - annual amounts and patterns

What are bands of rising and falling air currents?

at equator converging air currents bring moisture (tropical rainforest)

about 30° N&S diverging currents bring much less moisture (deserts)

further increases in latitude moisture increases (savannahs and grasslands)

between 40-50° N&S more rainfall (temperate forests)

60° N&S coniferous forests (taiga/tundra)

What do the 3 main belts of surface winds existing in each hemipshere do?

each one determines patterns of precipitation and the vegetation that develops

Tundra and boreal ecosystems biome characteristics?

acidity

waterlogging and frost

nutrient limitations

short life cycles

low functional dissimilarity

Temperate ecosystems biome characteristics?

variable pH

texture

variable nutrient availability

marked seasonality

high functional dissimilarity

What is an example of a temperate ecosystem?

west TN

Tropical ecosystems biome characteristics?

high precipitation

high nutrient availability

long life cycles

high functional dissimilarity

Arid ecosystems biome characteristics?

long, dry seasons

fires

low nutrient availability

short life cycles

low functional dissimilarity

What is an example of an arid ecosystem?

deserts

What are 3 principles of theoretical production ecology?

potential

limited

actual

What is potential production?

defining factors - climate, crop genetics, radiation, temp, CO₂, cultivar

genetic improvement

What is limited production?

limiting factors - water, nutrients, radiation, temp, cultivar, CO₂

yield increasing measures

What is actual production?

reducing factors - weeds, pests, diseases, pollutant

yield protecting measures

Description of tropical rainforests?

warm and moist year-round

highest biological diversity

most photosynthetically productive

soils are nutrient poor agriculture potential

Description of deserts?

very dry

hot days

cool nights with rapid temp loss

low fertility soils

low agricultural potential

irrigation and fertilization required for salt accumulation in the soil

Description of savannahs and grasslands?

soils rich in organic matter and nutrients

rainfall varies with season

agriculture potential

high potential if soils are not depleted or eroded

irrigation can be useful during dry periods

“bread-baskets of the world”

Description of temperate deciduous forests?

mostly hardwoods like maple, hickory, ash, oak

photosynthetically very productive but only for part of the year

soils have a shallow organic and nutrient-rich area

agriculture potential is high for few years but decreases unless soils are properly managed

Description of boreal coniferous forests (taiga)?

cool and wet

low biological diversity

soils are nutrient poor agriculture potential

Description of tundra?

ground permanently frozen below the surface

warming global temps are thawing the permafrost causing unstable ground and decomposing organic material releasing CO₂ and methane

very short season of where plants grow

low agriculture potential

What type of biome has been affected the most by human activity and why?

grasslands and temperate

are harvested and/or converted to farmland

Drainage systems radically changed many biomes to loss what?

wetlands

What local features of different biomes are affected that have microclimates within them?

hills, valleys, bodies of water, land masses, buildings

warmer or colder, hotter or cooler, wetter or drier

What do ecosystems need that plants sequester and expel in their biomass?

CO₂

What is the difference between sequestered and expelled CO₂?

net photosynthetic productivity (NPP)

What is NPP?

the amount of CO₂ removed from the atmosphere

How do plant communities in biomes change over time as the biome “matures”?

succession of plant species

How does the succession of plant species begin?

starts with pioneer species

Explain pioneer species?

first to establish after a change in biome by natural or human causes

allow for survival in new conditions

are displaced as niches develop in the system and then new plants will fill the niches

What are some examples of natural causes?

earthquake, volcano, glacier, fire

What are some examples of human activity causes?

fire, agriculture land preparation

What is the role of a climax community?

least and most stable group of plants

stays until a disturbance creates an imbalance

all locos in a geographic area tend to develop the same kind of vegetation over time

What is the impact of cultivating plants on the ecosystem and human footprint?

human activity influences about 35% of land surface and having this influence on almost all photosynthetically productive land

How can human impact on the environment by evaluated?

energy requirements and land use

How to evaluate energy requirements?

efficiency of technology

availability on national or global level

What is evaluated on land use?

human footprint

What is the human footprint?

space required for all the items used by individuals or populations

accounts for space required to produce what we use and absorb the waste we generate

What is the equation for the human footprint and explain it?

footprint = areas used x intensity of use

intensity of use includes energy and other inputs needed

the more energy efficient a process - lower the foorprint

How does energy contribute to much of our footprint?

fossil fuels do when extracting, processing, and distributing them

production of CO₂ from burning the fuel is the greatest contribution

What biomes allow for absorption of fossil fuel CO₂ emissions to stop rising of CO₂?

forests especially equatorial rainforests

farm crops but not as efficiently bc much CO₂ is released when crop is consumed

Wanting to save the equatorial rainforest from farmland development can cause what negative impacts?

economic loss

potential starvation for country

What type of credits are issued for reducing CO₂ emissions?

Carbon Offset Credits or Carbon Credits

What are “Carbon Offset Credits”?

they can be sold to rainforest countries for preserving their forests as CO₂ absorbers

What percentage does the US agriculture production of US energy?

2%

When taking into account all the energy cost of getting US food from field to table is estimated to be what?

10% of total energy production

What is the percentage if the entire world adopted the US from farm to table practice?

50% of global energy use