Week 9 - Biogeography Flashcards
What is biogeography?
“Biogeography is the study of the past and present geographic distributions of plants and animals and other organisms.”
What is biogeography concerned with?
The distribution of species.
What are the three main branches of biogeography?
Ecological, historical, and conservation.
What is the difference between ecology and biogeography?
Ecology is concerned with the relationship of species and their environment whereas biogeography is concerned with species and their distribution over space.
What are communities?
A community is formed by the interactions among populations of living animals and plants at a particular time and place.
What are habitats?
Within a community, a habitat is the specific physical location of an organism, i.e. where it lives.
What is a niche?
A niche is the environmental conditions under which an organism can survive.
For plant growth, what is light a critical part of?
The energy transfer process.
Photoperiod and intensity vary by what?
Latitude and season–the angle of the sun is important here.
Why does light depend on an organism’s position in the structure of the community?
This will affect how much light its receiving, i.e. if you live underneath a canopy.
What is the formula for photosynthesis?
carbon dioxide + water + light => glucose + carbohydrate + oxygen
What is the dominant factor in the formation of plant communities?
Competition for light.
What is the most important system for humans?
Photosynthesis.
What is the opposite of photosynthesis?
Respiration.
What is the formula for respiration?
glucose + oxygen => carbon dioxide + water + energy
What happens during respiration?
Carbohydrates are broken down into carbon dioxide and water.
When does respiration occur?
At night.
What does the overall growth of a plant require?
An excess of carbohydrates beyond what is lost through respiration.
Draw a diagram explaining the relationship between photosynthesis, respiration, and growth.
Photosynthesis: - In: light, carbon dioxide, water - Out: oxygen - gives sugars to plant growth Respiration: - In: oxygen - Out: carbon dioxide, water - gives energy to plant growth The difference between the two is net photosynthesis.
What is net primary productivity?
The net photosynthesis for a given community; the amount of stored chemical energy that the community generates for the ecosystem.
How is net primary productivity measured?
By fixed carbon per square metre for year.
What is biomass?
Biomass is the net dry weight of organic material.
Biomass is an indirect form of what?
Solar energy.
What are some examples of biomass as stored solar energy?
Charcoal, biogas, or alcohol, which are used as fuels.
Which areas have high terrestrial NPP?
Forests, especially tropical, and estuaries.
Which areas have low terrestrial NPP?
Grasslands and agricultural lands.
Which areas of the world have high and low NPP?
The tropics are high, arid and polar regions low (no vegetation).
What happens to NPP in temperate and high latitude regions?
Rate at which carbon is fixed varies seasonally.
What are the NPP rates like in the tropics?
High all year round (low seasonality).
What does temperature trigger and control in plant growth?
The stages of plant growth.
What happens to plant growth with temperature extremes?
It limits growth at temperature extremes.
Why do air and soil temperatures determine the rate at which plant growth proceeds?
Most chemical reactions are going to be governed to a certain extent by temperature.
How do plants survive below freezing?
They require special adaptations.
How do cold-blooded animals regulate body temperature?
They moderate their temperatures through their environment, by seeking warm or cold places.
How do warm-blooded animals regulate body temperature?
Through internal adaptation.
Organisms are limited by what?
The availability of water.
What does water availability depend on?
Evaporation, precipitation, and soil conditions.
How can organisms affect water availability.
Through plant transpiration.
What are xerophytes?
Organisms that are adapted to arid conditions, e.g. they reduce water loss with waxy leaves or no leaves at all.
How are xeric animals adapted?
They are nocturnal or have adaptations to conserve water.
What are the two most important variables that will determine the distribution of species?
Temperature and precipitation.
What is a keystone species?
The species that holds everything else together in an ecosystem.
What are stomata?
The pores on leaves; related to transpiration.
Who developed the concept of life zones changing with altitude?
Alexander von Humboldt
Whose textbook was based on von Humboldt’s work?
Mary Somerville’s
What did von Humboldt recognized could be exchanged for one another?
Altitude and latitude
Why does each life zone have its own biotic communities?
Because they have their own temperature, pp, and insolation.
Which mountains begin in tropical rainforests and go up to ice?
The Andes
How do we map species distribution?
With environmental or ecological niche models.
What are three questions that we ask when mapping species distribution?
- Where do species occur?
- Can we predict whether a species exists somewhere, even if we have no direct evidence?
- Can we predict the effects of climate change on that distribution?
What is a limiting factor?
The fact that the environment may inhibit biotic operations.
Limiting factors may be _____ or _____ in nature.
physical or chemical
What are some examples of limiting factors?
Low temperature, lack of water, low phosphorus content of the soil
What are three other abiotic factors?
Microclimate, slope and exposure, and magnetic field
How do microclimates affect an ecosystem’s climate?
If you’ve got one foot in boiling water and the other in a block of ice, then on average you are quite comfortable.
What do biogeochemical cycles do?
They enable the circulation of materials through ecosystems.
What are the two kinds of biogeochemical cycles?
Gaseous and sedimentary
What is an example of a sedimentary cycle?
Nitrogen going through the soil; the plants do not take nitrogen straight from the air, but must get it from the soil.
What is the carbon cycle?
It is a gaseous cycle in which carbon is fixed through photosynthesis.
How is carbon released into the atmosphere?
Through living organisms (respiration) and the burning of forests and grasslands.
Why does burning fossil fuels cause global warming?
There are large carbon storage pools in carbonate sediments and fossil fuels which, when burned, release the carbon into the atmosphere, causing global warming.
What is the oxygen cycle?
It’s a gaseous cycle in which atmospheric O2 is increased by photosynthesis.
How is atmospheric oxygen decreased?
By respiration, combustion and mineral oxidation.
What is the nitrogen cycle?
It’s a sedimentary cycle in which useful forms of bacteria or blue-green algae convert N2 found in the air to ammonia (NH3), which organisms are now able to use.
What are denitrifying bacteria?
Bacteria that remove nitrogen.
Which plants are nitrogen fixing bacteria associated with?
Clover, alfalfa, soybeans, peas, beans and ground nuts.
What does trophic refer to?
The feeding and nutrition relationships in an ecosystem; what is eating what.
What do trophic relationship represent?
The flow of energy and cycling of nutrients.
What are organisms that feed on others called?
Heterotrophs
What are organisms that are capable of dioxide as their sole source of carbon called?
Autotrophs
Where does most nitrogen fixation now come from?
Human fertilizers
What does harvesting mean for the nitrogen cycle?
- Nitrogen is lost and needs to be replaced with fertilizers.
- Fertilizers may run into streams and lakes causing dead zones.
What kind of nitrogen is usually found in the atmosphere?
N2
What does lightning do to nitrogen molecules?
The energy from the lightning splits them.
What happens to nitrogen molecules after lightning splits them?
The nitrogen atoms react with oxygen to form nitrogen oxides which the rain washes into the ground, forming nitrates.
Are heterotrophs herbivores, carnivores, or omnivores?
They can be all three.
What is the flow of energy from producers through a system called?
The food chain.
What is a food web?
Within ecosystems the feeding interrelationships are complex and arranged in a complex network of interconnected food chains called a food web.
What is the difference between the food web and a food chain?
The food web is the way the world is; the food chain is just one component.
What is the final link of a food web or food chain?
Decomposers.
What do big carnivores need more energy?
Because of the 10% rule.
What is the 10% rule?
When you consume, 90% is used for life support and 10% goes to growth, which means that as you go up the food chain, you need 10x the amount of food to get your 100% energy.
What is environmental niche modelling?
The process of using computer algorithms to predict the distribution of species over a geographical space.
What is the basis of the computer algorithms for environmental niche modelling?
Mathematical representations of their known distribution in environmental space or their ecological niche.
Why do environmental niche models and the Köppen climate classification look so similar?
Because the Köppen classification is based on precipitation and temperature, which are the main two determining factors in species distribution.
Where does the major part of the mass of an organism come from?
From carbon dioxide in the atmosphere.
What are GIS layers?
Geographic Information System layers; a GIS is a computer system designed to deal with spatial and geographic data.
Ecological niche models are made from what?
GIS layers
How is biomass generally measured?
By weight and area.
NPP is measured in terms of what?
Carbon
Who was Alexander von Humboldt?
The guy who figured out that altitude and latitude could be exchanged for one another in terms of life zones; he did most of his work in the Andes; Mary Somerville’s textbook was largely based on his work.
What is the difference between ecology and biogeography?
Ecology is the study of the relationship between species and their environment, whereas biogeography deals with the distribution of species over space.
What is the difference between a biological community and a habitat?
The community is the interaction of species within an area whereas a habitat is the actual physical location of an organism, i.e where it lives
