Lesson 9 Flashcards
What is the definition of biodiversity?
The number of species that occupy a certain area, genetic variations or the role that species play within an ecosystem.
What is one of the most important factors supporting high species biodiversity in mountains?
The diversity of habitats that result from a rapid change in elevation on mountain slopes. Otherwise known as microclimates that lie along the vertical elevation gradients.
Who was one of the first people to document the patterns of mountain biodiversity?
Alexander Von Humboldt - a Prussian geographer and naturalist, in the 1800s.
The cross-section sketch of Chimborazo (a Stratovolcano in Ecuador) depicts what phenomenon?
The distribution of species along gradients of varying physical conditions - drawn by Alexander Von Humboldt.
Who laid the foundation for the entire field of biogeography?
Alexander Von Humboldt
What is the highest mountain in Ecuador?
Chimborazo - a Stratovolcano.
What is speciation?
Speciation - occurs when populations genetically diverge to the point where they are no longer able to interbreed.
What must happen for speciation to occur?
Populations must be isolated, so there is no movement of individuals from one place to another.
What is allopatric speciation? Where is this a common occurrence and why?
The isolation of a species through geographic isolation. It is common in mountains because these rugged landscapes impose topographic barriers that isolate smaller populations.
What can be explained as the cause of genetic and morphological variations in the Tyrian Metaltail (humming bird)?
Geographic isolation or allopatric speciation
What factors contribute to the high diversity of bell flowers?
Combined effects of climate oscillations, rugged alpine habitats and variable floral morphology as well as geographical isolation between multiple mountain refugia.
What are refugia?
Refugia are places in the mountains that have maintained favourable conditions during periods of past environmental change - often associated with periods of glaciation.
What are the three measures of biodiversity?
1 - Species richness
2 - Evenness
3 - Species diversity
What is species richness?
The simplest measure of biodiversity - which is the count of the total number of species present.
What is evenness?
Measures how similar species are in their relative abundances.
What is species diversity?
A measure of biodiversity that accounts for both species richness and and evenness.
What is DNA barcoding?
An increasingly popular way to assess biodiversity. It is a technique used to characterize species, using a short DNA sequence. It also provides a measure of genetic diversity within populations and communities.
True or False: If there are large differences in the abundance of species, then a community has high evenness.
False - A large difference would indicate a low evenness.
True or False: mountain regions contain a low proportion of endemic species.
False - endemic species are unique species. These species are found in mountain regions and nowhere else in the world.
What small endemic species is found only in the Rocky Mountains? Describe this species.
The Banff Spring Snail or Physella johnsoni. This is a small freshwater snail. It is unique because it has adapted to life in thermal springs, where water is low in oxygen and high in hydrogen sulfide. They are omnivores!
When was the Banff Spring Snail first identified?
In 1926 at sulfur mountain in Banff National Park - they have not been found anywhere else.
What is threatening the Banff Spring Snail?
The ponds they live in are prone to drying up. Now the snails are listed as endangered, so they are highly protected.
What is a diversity hotspot?
Regions containing high concentrations of endemic species that are also facing threats of rapid species loss.
How many biodiversity hotspots have been identified throughout the world? How many of them are located in mountain regions?
35 - half of which are located in mountain regions.
How much of the earths land area are represented by biodiversity hotspots?
2% - yet they are home to half the worlds endemic species.
What explanations can be used for the concentration of endemic species, found in the Andes of South America?
1 - past climate shifts
2 - Tectonic events
3 - modern ecological interactions
4 - limited dispersal
Upland areas were isolated from the lowlands, but the Andean uplift which began 25-30 million years ago. This eventually created a complex mosaic of high mountain and deep valleys. This was an important driver for speciation, resulting in high concentrations of endemic species (birds, mammals, amphibians and plants).
What two hypotheses can be used to explain the patterns of biodiversity in mountain regions?
1 - The geographical area hypothesis
2 - The Productivity hypothesis
What is the geographical area hypothesis?
According to this hypothesis, larger areas can support more species - therefore decreasing species diversity at higher latitudes and elevations, my just be a consequence of less habitat availability.
What is the Productivity Theory?
This hypothesis proposes that the amount of primary productivity, which forms the resource base of food webs, determines the number of species that can be supported in an area - therefore higher primary productivity (associated with higher temperatures in the tropics and at lower elevations) contributes to higher biodiversity.
What is a nunatak?
The tops off mountains that are sticking out of ice sheets. - the most famous one is in Greenland. It is located over 100km from any ice-free area, and it supports the growth of plants.
What will happen to the nunataks, as a consequence of global warming. How will this impact the especially found on nunataks?
As ice melts, the nunataks will become connected by ridges. The once endemic (isolated) species found on nunataks will travel along the ridges and mingle with other species causing changes in their evolution.
Why is it important to maintain mountain biodiversity (beyond its aesthetic value)?
It’s critical to the functioning of mountain ecosystems. It acts as insurance - buffering ecosystems against losses of individual species in the face of environmental change. Increases the probability that mounting ecosystems can cope with environmental changes.
What is the biodiversity of plants in mountain regions critical for?
Slope stability. (Decreases the risk of erosion, landslides, avalanches and degrading the quality of water sources).
What is the diversity-stability hypothesis?
This hypothesis is based on the observation that species vary in their morphology and physiology, and that in a highly diverse system, there will be some species that can compensate for the loss of others after disturbance. Thus species-rich systems are considered to be more stable and more able to withstand environmental disturbances.
What doe the terms Ecosystem Services mean and when was it defined?
All the values associated with the preservation of ecosystem is called Ecosystem Services. This term was defines in the 2005 Millennium Ecosystem Assessment as a way of quantifying the benefits people obtain from both natural and managed ecosystems.
What physical characteristics of high mountain ecosystems, must living organisms contend with?
1 - Lower partial pressures of O2, CO2 and water vapour
2 - Lower temperatures
3 - greater solar radiation and increased fraction of ultraviolet radiation
4 - Slope aspect/steepness
5 - poor soil development
6 - wind
Define a conifer plant.
Conifers reproduce from seeds in cones and have needle-like leaves.
What are the adaptations of coniferous trees that help them to thrive in the colder/dryer conditions at higher altitudes?
1 - Their needles/leaves have a smaller surface area that sheds snow
2 - Their needles have a waxy coating that helps them retain moisture and protects them from UV radiation
3 - they have narrower transport vessels (tracheids) which decrease the likelyhood that a gas bubble will develop in winter
4 - have extensive root systems that allow them to receive water and nutrients from the soil
5 - can photosynthesize at relatively high rates, even at colder temperatures
What is a cuticle?
The waxy coating around the leaves/needles of coniferous trees (helps them to retain moisture and provides protection from UV radiation).
What is photosynthesis?
The process by which plants use light energy, combined with CO2 and Water to make sugar (converted into biomolecules) and oxygen.
Why are conifers able to photosynthesize for longer periods of the year?
Because they are evergreen trees.
What is a tracheid?
Smaller vessels found in conifers that decrease the likelyhood that gas bubble will develop in winter (blocking the flow of water and nutrients).
Where can the white bark pine be found?
High elevations of the Rocky Mountains.
When to white ark pines reach their full reproductive potential?
Not until they are 60 -100 years old.
What’s so special about white-bark pine and Limber pine trees?
The whitebark pine is considered a keystone species because it regulates snowmelt in specific regions - preventing snow melt and delaying it into the summer time.
How are whitebark pine adapted to fire?
The seedlings of whitebark pine can’t stand a shaded area to grow on, they need an open stand. Their seeds are dispersed solely by Clark’s nutcracker (bird) who poops them out in areas that are open or have recently been disturbed by fire.
What are the threats currently to whitebark pine?
1 - Change in the fire regime (reintroduction the natural fire process will help the whitebark pine species)
2 - Climate change
3 - Introduced pathogen (white pine bliserex) - fungus
What key elements can be used to identify a limber pine tree?
1 - 5 needle pine
2 - Has pollen cones (collect and distribute these seeds)
How have larches adapted to living at high elevations - despite not being evergreen trees?
1 - Develop softer more fragile leaves (less of a costly investment)
2 - They flower more early in the spring and photosynthesize more efficiently
3 - they are highly efficient at extracting nutrient from their needles back into their wood tissue before dropping their needles in the fall.
How do alpine plants stay warm in high elevation environments?
They do so by using 2 pathways: either they increase the amount of warmth they absorb from the sun (radiative heat gain), or they decrease the amount of heat lost through convective cooling.
They do this by:
1 - having dark colouring (absorbs more heat)
2 - orienting their surfaces so they are perpendicular to the sun (absorbs more heat)
3 - growing in sheltered microclimates (decreases convective cooling)
4 - forming a hairy surface (pubescence)
5 - growing close to the ground to avoid wind and for shelter under the snow (subnivian space)
Boundary layers in high alpine plants are created by the formation of… ?
Pubecence - hairs that grow on the plants surface that reduce convective cooling
What is subnivian space?
The space below the snow that helps protect alpine species (insulation and protection during the winter)
What is a cushion growth form? How do they help alpine plants stay warm?
Tightly packed clusters of smaller stems.
Cushion growth forms increase radiative heat gains of the plant as well as restrict air movement through the low canopy. They can be up to 15 degrees warmer than the surrounding air temperature.
What is meant by the term Ecosystem Engineers? What plant type is an example of this?
Organisms that modulate the availability of resources to other species through habitat modification.
Cushion growth systems are an example of this because they have their own mini ecosystem that recirculates nutrients.
What is the rossete growth form?
The rossete growth form is common in alpine environments. It consists of individuals with a circular, basal arrangement of leaves, with erect flowering stems.
The rossete growth for is an adaptation for what?
1 - seed dispersal
2 - attracting pollinators
What is Espeletia Schultzi? What adaptations does this plant have to withstand the cold?
A rossete species found commonly above the treeline in the Venezuelan Andes.
This plant has marescent leaves (super hairy stems) that senesce but do not fall off the plant, providing protection from the cold.
What three physiological adaptations have alpine plants developed to help prevent their tissues from freezing?
1 - Freezing point depression (reducing temperature at which they freeze)
2 - Supercooling (allows water in plant cells to cool bellow 0, preventing ice formation)
3 - Dehydration by ice segregation
What is the concept of Freezing point depression?
This is an adaptation that allows plants to increase the concentration of soluble sugars in their tissues which decreases the temperature at which they freeze.
What is supercooling?
An adaptation of high alpine plants that allows water within their cells to cool brow 0 degrees, preventing ice formation.
How does plant dehydration impact their freezing tolerance?
Alpine plants have adapted to be able to move water out of their cells to the otherwise empty spaces, where it wont harm their tissue if it freezes.
Transpiration involves both…. ?
The transport of water within a plant as well as the loss of water from a plant to the atmosphere through evaporation.
Where and when is carbon dioxide received by plants?
Carbon dioxide is absorbed into plants at the same time that water is evaporated from the surface of the leaves through specialized pores called Stomata.
What drives the transpiration process in plants? What adaptation can reduce transpiration?
The water-potential gradient (moisture within the leaf relative to the surrounding area). The formation of boundary layers (formed by little hairs) can reduce transpiration.
True or false: transpiration decreases at high elevations.
False - transpiration INCREASES at high elevations (lower atm, and high winds in alpine areas, mean that less water is held in the air. Thus the water-pressure gradient is increased causing more transpiration).
What do alpine plant leaves and the needles on coniferous trees have in common?
They both have cuticles (waxy coating) that help seal in moisture.
What is the cost of alpine plants closing their stomata to reduce water loss?
It decreases their potential to photosynthesize, as they are unable to take up as much CO2 into the plant.
What root system is often sound in alpine plants?
A taproot system - this system has a large and long main root that goes straight down with smaller roots coming off the side.
Allow plants to reach more nutrients and provides stability.
True or false: a low root-to-shoot ratio enables higher stored levels of water and nutrient
False: a HIGH root-to-shoot ratio enables higher storage of water and nutrients. (Allowing plants to grow immediately as temperatures increase in the spring)
What are 3 examples of alpine flowers with deep-rooted systems?
Pasqueflowers
Gentians
Oxytropes
Lichens are a symbiosis between which two species?
Algae (bacteria) and fungus!
How do the component of lichen (algae/bacteria and fungus) support each other in survival.
The algae/bacteria photosynthesize to produce food energy that it shares with the fungus and in return the fungus provides shelter and a site on which the bacterium can grow.
What is a mutualistic association?
A relationship between two organisms in which both benefit (symbiosis).
How do lichens revive nutrients?
They obtain nutrients from the atmosphere as well as soluble nutrients from the surface they live on by releasing biochemical enzymes that decompose the substrate they live on (even if its a rock) so they can eat it.
What happens when lichens dry out?
They enter a state of dormancy until wetter conditions return. When water does return they absorb it rapidly.
What is the lowest temperature at which lichens can photosynthesize?
Any temperature above 0 degrees Celsius.
Define a perennial.
A plant that persists for more than 2 years
What is an annual?
Plants that complete their entire life cycle in one year and then die.
How long can alpine perennials live?
Hundreds of years.
Are perennials or annuals more suited to alpine environments? Why?
Perennials are more suited to alpine environments because they can persist through tougher years and reproduce when conditions are favourable. Annuals are less suited to alpine environments because they can cease to survive a bad growing season - which may occur frequently in the harsh environments of mountains.
What form of asexual reproduction is common in alpine plants? What is the benefit of this type of reproduction?
Vegetative reproduction - in which new plants grow from part of a parent plant. This is advantageous because the plant can survive and reproduce, even in harsh conditions. Sexual pollination is challenging in alpine environments because the density and diversity of pollinators is low and the viability of seeds is strongly influenced by environmental conditions.
In alpine environments, the asexual reproduction of plants is commonly achieved using…. ?
Rhizomes - modified ground stems that extend away from the plant and grow new shoots.
When do most alpine flowering plants bloom? Why?
Within a few weeks following the snow melt. This allows them more time to attract pollinators.
What adaptations do alpine plants have to attract pollinators?
Alpine plants form warmer microclimates around their flowers for pollinators. Flowers are often darker in colour, and cup shaped, which focuses solar radiation towards the centre of the flower and increases temperature. This causes insects to seek refuge in flowers, increasing opportunities for pollination.
By how much does solar tracking in the snow buttercup enhance pollen germination?
By up to 44%
Define co-evolution.
When two or more species reciprocally affect each others evolution.
What are the most important pollinators in mountain ecosystems?
Bumble bees and flies
Contrast the pollination strategies of bumble bees versus flies.
Bumble bees are specialist pollinators that preferentially visit plants with adaptations that match their morphology.
Flies are generalist pollinators that visit a wide variety of unspecialized plants.
What are the preferred colours of bee pollinators?
Bright blue and yellow flowers.
Why do fly pollinators prefer white flowers?
Because they are colour blind. They do not have a preference for colour and thus, the flowers have no use in producing colourful floral displays.
