Virtual Vista Science 20 unit D conclusion

Virtual Vista Sci 20, Units D

Abiotic factor

physical non-living part of an environment that influences living things and ecosystems. Primary factors include: light, ph, temperature, water, nutrients, and the wind.

Biotic factor

living components of an environment that influences other organisms and ecosystems.

Ecosystem

all organisms in an area, along with the abiotic factors they interact with.

Habitat

all abiotic and biotic factors in an area that make up an organisms living space.

Algae

microscopic, photosynthetic organisms; found in marine and freshwater environments.

Harmful algae bloom

rapid algae growth, blocks out the sun; killing plants therefore depleting the water of oxygen.

Why is water considered the ‘natural solvent of life’?

ionic compounds can be easily dissolved in water, then able to be carried through fluids like blood or sap to different cells/tissues.

What are the effects of salinity in water?

Makes water undrinkable, affects seed germination and plant growth. Saltwater is damaging to most plant and aquatic life and changes the ecosystem.

Anoxic

water deprived of oxygen

Run off

nutrients dissolved in water can flow into bodies of water, and cause increased algal blooms and eutrophication.

Eutrophication

The nutrients (like Nitrate and phosphate) from run off promote increased algae growth, where the normally invisible now form huge colonies. As they deplete the excess nutrients, they die in great numbers. Their decomposition requires oxygen, leading to anoxic conditions; killing off other organisms.

What does it mean when its said: “using too much fertilizer can cause salt contents to get ‘too high’”?

It is when the concentration of ionic compounds (salts) becomes too high, due to a lack of water used to fully dissolve them.

Biomass

the dry mass (weight without water) of all living organisms in a habitat

Ecology

study of living things and their interactions w/ other living things and the environment

Population

Group of organisms of the same species, who interbreed and live in the same area.

Biological community

Interacting populations in the same area at the same time

Symbiosis

long lasting, ecological relationships, benefitting at least one of two close contact species.

Mutualism

a symbiotic relationship where both organisms benefit

Commensalism

a symbiotic relationship where one benefits and one is neutral, neither benefitting nor being harmed by the other.

Parasitism

a symbiotic relationship where one benefits at the detriment of the other (host).

Competition

an interaction where two species compete for one resource.

Predation

an interaction where predator kills prey (some benefits; sick/weak/old filtered out)

Functions of bacteria, fungi, and other microscopic life forms?

They break down key nutrients (nitrogen, phosphorus) into forms useable by plants. An example of this is how they decompose dead leaves and animal droppings in soil; releasing the nutrients and making them available for plant life.

Functions of prairie dog burrowing?

Aerates soil, and churns in plant and animal waste. By shortening the grass, insects are easier found, and increases the plants nutritional value.

Functions of bison activity?

Enjoys the more rich plants/grass derived from prairie dog activity, and also shortens by eating only the tips of grasses. They compact soil which makes it easier for prairie dogs to burrow.

What is one way organisms can be grouped?

By what they eat.

Producers

use light energy to synthesize sugars and other organic compounds (photosynthesis).

Consumers

Uses other organisms as a source of energy

Primary consumers

organisms that eat green plants, algae, or phytoplankton, which are their source of energy. Can be herbivore or omnivore.

Secondary consumers

Organisms that eat primary consumers (herbivores), which are their source of energy. Can be carnivore or omnivore.

Tertiary consumers

Organisms that eat secondary consumers, which are their source of energy. Can be carnivore or omnivore.

carnivore

kills and eats other animals

omnivores

eats both plants and animals

herbivore

eats only plant life

Scavenger

feeds on dead/decaying animals it did not kill

Decomposer

organisms who break down complex organic molecules into simple ones

trophic level

energy transfer level (ex: energy in plant transferred to herbivore); used to divide species in ecosystem based on their energy source.

Why are food webs superior to food chains in the general sense?

Food chains are a gross oversimplification.

What is the energy loss between trophic levels?

90%, only 10% of energy passes into the proceeding level (1000kcal → 100 kcal, from producers to primary)

Explain the energy transfer procedure in the grasslands.

The primary energy source is light energy, from the sun. The producers store this energy in large molecules, in forms of sugar, starch, fat, protein. Herbivores eat these producers, and gain the energy, then carnivores eat them and gain the energy. Each step in this cycle is called a trophic level. Only 10% of energy is transferred between levels, the rest lost as the organism uses them, as heat.

Explain why chemical concentration increases by trophic level.

because organisms in higher trophic levels have to eat more to gain their required energy. As only a percentage of the initial energy is in their food source, they accumulate a higher amount of chemicals. For example: if a grasshopper contains 5 units of DDT, and one bird consumes 100 grasshoppers to meet their energy requirement, the bird has accumulated 500 units of DDT.

What are the types of energy pyramids?

1. Percentage of original solar energy transfer, where it starts at 100% and each trophic level is 10% of the previous. (100% available energy found in consumers → 10% available energy found in primary consumers, where 90% was used to support bodily functions; left as heat. Each transfer leaves 10% of the previous).

2. Dry mass at each level; biomass. By calculating using dry weight, you can account for size of organism. (3000 kg of producers support 200 kg primary consumers and so on)

3. Numbers at each level; does not account for size. (1 billion grasses → 100 thousand grasshoppers → 500 birds)

Baseline

fixed starting point for measurements

Transects

a line or path along which samples are collected, perpendicular to baseline.

Are baselines and transects better for measuring mobile or non-mobile species?

Non-mobile, such as the plant population. Animals may be measured by footprints/droppings.

Can water leave biosphere?

No.

Transpiration

loss of water vapor from a plant through it’s leaves

Humidity

an atmospheres moisture content

Biogeochemical cycle

diagram representing movement of elements and compounds between living and non-living components of an ecosystem

Photosynthesis

process where plants and certain organisms use light energy to convert water and carbon dioxide into oxygen and high energy carbohydrates, such as sugar and starches.

Cellular respiration

process where cells convert chemical energy stored in sugars into energy they can use

Carbon sink

system that removes more carbon dioxide than it releases into the atmosphere.

Peat/Moskeg

deep layers of mosses and plant remains unable to fully decompose due to a lack of oxygen.

Photosynthesis

energy from the sun is used by producers to convert co² gas into energy rich glucose (sugar) to be used as food and energy.

What do the formulas of photosynthesis and cellular respiration have in common?

They are the reverse of each other.

photosynthesis:

sun energy + 6 H₂O + 6 CO₂ → C₆H₁₂O₆ + 6O₂

cellular respiration:

C₆H₁₂O + 6O₂ → energy + 6 H₂O + 6 O₂

The oxygen cycle has the same biogeochemical cycle as the carbon cycle

How does air temp affect evaporation?

When the air is warmer, it can hold more water. High temps and wind increase evaporation.

**the higher energy increases potential of lone molecules to overcome the hydrogen bonds formed by the presence of hydrogen atoms—which were keeping the individual molecules connected as a cohesive body of water.

How do forest fires contribute to run-off, and subsequently erosion?

As organic matter burns, hydrocarbon compounds are broken into their basic components. As they trickle down into the cooler soil particles, they condense and create a waxy, waterproof layer over the soil. This layer lasts 1-2 years, and prevents rain water from being absorbed—instead becoming run-off and increasing erosion. The process changes the landscape, and diminishes the quality of the run-off water.

How do humans affect water quality?

Any water used is returned with diminished quality.

How does deforestation contribute to run-off?

Forests shade snow so it runs-off later, and hold water. Deforestation means run-off happens too quickly to be utilized effectively, and increases evaporation. (melted snow usually helps when rivers fall low during summer)

How are photosynthesis and cellular respiration connected in plants?

Most carbon from photosynthesis is stored in a plants leaves. Photosynthesis produces oxygen and sugars (chemical energy). That same oxygen is then used in cellular respiration to break down the sugars and release energy

How do peats/carbon sinks work?

plant dies in a area with little oxygen— like a swamp— where decomposers cannot break down. This carbon stays stored in the plant, and subsequently the peat.

Why is deforestation and burning fossil fuels a bad match up?

The burning releases tons of CO₂ into the air, and the trees who would be removing said carbon have been removed. Wildfires do something similar, but instead releases stored carbon.

Why is said that the carbon cycle is a small part of the oxygen system?

Oxygen composes 21% of the atmosphere, while carbon dioxide is only 0.03%

Nitrogen Fixation

Nitrogen gas becoming ammonia

Nitrogen fixing bacteria

Converts the nitrogen gas found in the atmosphere into ammonia which can be present in the soil

Nitrification

Ammonia becoming nitrates/nitrites

Nitrifying bacteria

Converts ammonia into useful forms of nitrogen that plants can use

Denitrification

nitrites/nitrates in soil leaving to become nitrogen gas in atmosphere

Denitrifying bacteria

takes the nitrites/nitrates out of the soil, having them leave in the atmosphere as nitrogen gas. Used to treat sewage.

Why are legumes (beans, peas, soybeans, etc) important for nitrogen fixation?

Legumes have a symbiotic relationship with nitrogen fixing bacteria, thus can pull nitrogen gas from the air. Also, when they decompose, they release ammonia into the soil. Fertilizers made up of these compounds, like hummus, increase nitrogen in soil.

Why do plants require nitrogen gas to be converted into nitrites/nitrates?

The atmosphere contains 78% of nitrogen that plants cannot directly use. For soil to absorb the gas, there must be legumes present to fix the nitrogen into ammonia, where nitrifying bacteria can then convert it into nitrites and nitrates.

also need to pull it from their root system, and not the atmosphere

How does lightning increase nitrogen levels in the soil?

The high energy lightning bolt break nitrogen molecules in the atmosphere, which then run to stabilize themselves, reacting with oxygen to form Nitrogen Oxide. NO dissolves in rainwater, forming nitrates, then entering the soil.

Importance of nitrogen?

Essential for proteins, DNA, RNA in all living organisms. Is a key component of chlorophyll, which enables photosynthesis.

How do wildfires and fossil fuel combustion affect nitrogen?

releases stored nitrogen, which leaves as nitrogen oxide, causing acid rain and climate effects.

Lichen

example of mutualism, a symbiotic association between a fungus and a photosynthetic alga forming a hybrid species. Takes 80 years to form and a staple of caribou diet.

Habitat fragmentation

separating one habitat into smaller subsections. Can be natural or man-made. Can stagnate the gene pool of a species by splitting them up in smaller chunks.

Invasive species

Outsider species, introduced by humans, becomes a breeding population and threatens an areas biodiversity. Most alien species die out, but in some cases outcompete original species causing environmental destruction.

Biodiversity

variety of life in all forms, mostly in one ecosystem. In species, little biodiversity leads to inbreeding.

Why is it foolish to let species fall into extinction?

40% of medicine drugs based on compounds in natural species, and only a fraction of species have been tested. Potential cures for major diseases falling into extinction would be detrimental.

What are the 5 labels that represent a species population level?

Extinct: species no longer exists anywhere

Extirpated: exists, but elsewhere

Vulnerable: likely to become threatened or endangered

Threatened: likely to become endangered if vulnerabilities not addressed

Endangered: threatened with extinction/extirpation

Habitat destruction

permanent alteration to a habitat

Succession

predictable changes which occur in a community, lead to the development of an ecosystem

Primary succession

change occurring in an area where no soil existed; bare rock to complex community.

Secondary succession

change occurring in an area with soil present; happens extremely quickly compared to primary.

What is the primary cycle?

over thousands of years…

• begins with bare rock →

• pioneer species, mosses & lichen, populate, help break down the rock, then eventually decompose to form ‘soil’ (humus) →

• seeds disperse and fall into the soil leading to plant growth

What is the secondary cycle?

over a shorter time span…

• begins with soil present →

• low growing plants populate →

• trees appear and develop

Humus

organic compound of soil-equivelent formed from decomposed bodies of organisms

Pioneer species

plant-like/plants able to grow on rock, who invade and colonize barren ground.

Climax community

the final, most stable community emerging from those most competent to survive in an area. All else died off or left in the competition for survival.

Terraforming

process of transforming a planet to be more earth-like.

Aquatic succession

change occurring in an area with water present

What is the aquatic cycle?

• begins with runoff collecting in a ground depression (hole), called a basin →

• starts off low in nutrients, alga colonizes and provides food for other organisms. Frogs/salamanders/insects lay eggs →

• seeds and fish eggs latched onto birds fall into basin as they come to drink →

• sediment runoff/decomposing bodies increase the basins bottom layer, creating aquatic soil where plants can anchor and grow →

• as the sediment layer continues developing, the dugout shrinks in diameter, and becomes shallow →

• Plants like cattails and reeds begin to grow on the water’s edge. The increased vegetation turns the area into a marshy bog →

• At this stage, the aquatic environment begins to transition into a terrestrial one, where other plants from the surrounding ecosystem will begin growing in the bog

How do cracks in rocks increase rate of succession?

More soil can collect in the cracks speeding up the process.

How does more biomass (plants, decomposers, etc) increase rate of succession?

More species means faster accumulation of organic matter as organisms dies and decompose.

Sustainable development

development that meets needs of present without comprising needs of the future.

what are the four forest harvesting methods?

• Selection cut: predetermined percentage of marketable timber; typically older, less healthy trees.

• Clear cutting: all merchantable timber cut

• Shelterwood cut: most merchantable timber cut, leaving a few clumps

• Seed tree cut: leaves mature trees if they spread seeds

what are the advantages and disadvantages of the four forest harvesting methods?

Selection cut:

• Advantages: low usual impact, enough trees left over as cover for watersheds & wildlife. Variety of different age trees remain

• Disadvantages: some residual trees can be scuffed or damaged during removal process— leads to decay or disease.

Clear cutting:

• Advantages: all timber for the lowest cost

• Disadvantages: unsightly results, reduces biodiversity when reforestation uses a single species

Shelterwood cut:

• Advantages: some trees left to help reforest and for wildlife

• Disadvantages: still unsightly, though better than clear cutting

Seed tree cut:

• Advantages: leaving natural selection to run its course

• Disadvantages: some seed bearing trees are shallow-rooted (susceptible to toppling over). Even w/ seeds, reforestation must be initiated within two years.

Summary: Selection cut has the least damage in terms of habitat destruction, while clear cutting has the most.

How does bacteria multiply?

divides into 2, then those halves divide themselves into 2 outputting 4 total bacteria, and so on.

Doubling time

amount of time it takes for a population to double in size

Exponential growth

rapid growth in population, constant increase, little to no restriction