Ecology and Habitats Flashcards

A comprehensive set of 110 question-and-answer flashcards based on the Ecology and Habitats lecture, covering habitats, ecosystems, limiting factors, tolerance ranges, transects, coral reefs, biomes, climographs, and plant/animal adaptations.

What is a habitat?

The physical environment in which a community, species, population, or organism normally lives.

Which components of an ecosystem does a habitat represent?

The abiotic components of an ecosystem.

What can habitat descriptions include?

Geographical and physical locations, or the type of ecosystem.

How is a population defined in ecology?

A group of the same species living in the same area.

How is a community defined in ecology?

A group of populations living and interacting with each other in an area.

What constitutes the abiotic environment of an ecosystem?

The non-living physical and chemical environment that forms the habitat.

What formula expresses the relationship between an ecosystem, a habitat, and a community?

$$\text{Ecosystem} = \text{Habitat} + \text{Community}$$

Which syllabus reference covers 'Habitat as the place in which a community, species, population or organism lives'?

B4.1.1

In ecological organization, what level is formed by a group of organisms of the same species?

Population

In ecological organization, what level is formed by multiple groups of different populations interacting?

Community

In ecology, what is a limiting factor?

A variable that limits a population's distribution or numbers.

What do limiting factors determine for any given organism?

The optimal survival conditions for the organism.

How does light intensity act as an abiotic limiting factor in plants?

It affects the rate of photosynthesis (primary production).

How does temperature function as a limiting factor in living organisms?

It regulates the rate of enzyme-catalysed reactions in living organisms.

What are edaphic factors in an ecosystem?

Soil components (such as soil pH and mineral content) that impact nutrient uptake.

How do climatic factors act as abiotic limiting factors?

Factors like rainfall, humidity, and gas concentrations influence metabolic processes.

Which syllabus reference addresses 'Abiotic variables affecting species distribution'?

B4.1.3

What biological process in plants is directly affected by light intensity as a limiting factor?

Photosynthesis (primary production)

What molecular regulators in living organisms are regulated by temperature as an abiotic limiting factor?

Enzymes (regulating enzyme-catalysed reactions)

Give two examples of edaphic soil components listed in the lecture notes.

Soil pH and mineral content.

Name three climate variables mentioned that influence metabolic processes in organisms.

Rainfall, humidity, and gas concentrations.

What does an organism's range of tolerance represent?

The survival thresholds of an organism for a specific limiting factor.

What happens to the rates of survival as a population is exposed to abiotic extremes?

The rates of survival begin to drop.

In a range of tolerance graph, what is the optimal region where the highest population density occurs called?

Preferred niche

In a range of tolerance graph, what are the regions flanking the preferred niche where survival rates decrease called?

Marginal zones (zones of physiological stress)

In a range of tolerance graph, what are the outer regions where abiotic extremes prevent survival called?

Unavailable zones (zones of intolerance)

Which syllabus code covers 'Range of tolerance of a limiting factor'?

B4.1.4

What term refers to the full span of an abiotic variable between lower and upper survival thresholds?

Tolerance range

Look at this range of tolerance graph. What region is represented by the central peak under the bell curve?

Preferred niche

What is the population size in the 'unavailable' zone of a range of tolerance curve?

Zero (organisms cannot survive beyond their tolerance limits).

What is a transect in ecological studies?

A straight line along an abiotic gradient from which population data is recorded.

Why are transects utilized by ecologists?

To assess species distribution in correlation with an abiotic factor that varies across a measurable distance.

What tool is placed along a transect line to systematically record population data?

A quadrat

What graphical representation is used to show changes in species distribution along a transect line?

A kite graph

On a kite graph, what does the relative width of each 'kite' represent?

The abundance of an organism at a particular point along the length of a transect.

Look at this field work illustration. What method are the students using to sample organisms along an abiotic gradient?

A transect line combined with quadrat sampling.

Look at this kite graph. What does the horizontal axis marked from 100 m to 1100 m represent?

Distance along the transect line in meters.

On a kite graph, how is abundance plotted relative to the species baseline?

Symmetrically above and below the baseline line, creating a kite shape.

What feature systematically varies across space along a transect line?

An abiotic gradient

How does a narrow width on a kite graph compare to a wide width in terms of organism numbers?

A narrow width indicates low abundance, while a wide width indicates high abundance.

What type of organism forms coral reefs and exists in symbiosis with algae?

Reef-building coral polyps

What are the photosynthetic algae that live in symbiosis with reef-building corals called?

Zooxanthellae

Why are water depth and water clarity critical abiotic factors for reef-building corals?

They are critical factors for light availability required by photosynthetic zooxanthellae.

How does ocean pH impact reef-building coral structure?

It impacts the formation of the coral exoskeleton (composed of calcium carbonate, $\text{CaCO}_3$).

What chemical compound makes up the exoskeleton of reef-building corals?

Calcium carbonate ($\text{CaCO}_3$)

What happens to reef-building corals when exposed to unusually high water temperatures?

High temperatures lead to the expulsion of zooxanthellae algae (coral bleaching).

How does water salinity affect coral polyps?

It affects the osmotic pressure regulation of the coral.

Which syllabus code corresponds to 'Conditions required for coral reef formation'?

B4.1.5

What is coral bleaching?

The expulsion of symbiotic zooxanthellae algae by coral polyps due to unfavourable abiotic conditions.

Why does a bleached coral eventually start to die?

Because losing zooxanthellae deprives the coral polyps of their primary food source, causing them to starve.

Within what latitudinal boundaries is reef-building coral distribution limited globally?

Between $30^\circ\text{N}$ and $30^\circ\text{S}$ of the Equator.

Look at this distribution map. What ecosystem's global range is marked by the red dots?

Coral reefs (reef-building corals).

Why is reef-building coral distribution restricted to shallow waters?

Shallow waters receive sufficient sunlight for zooxanthellae photosynthesis.

Why are reef-building corals found primarily in tropical and sub-tropical regions?

Tropical and sub-tropical waters provide the warmer ocean temperatures required for coral survival.

Why do bleached corals appear stark white?

Expelling zooxanthellae reveals the translucent coral tissue over its white calcium carbonate ($\text{CaCO}_3$) exoskeleton.

What is a biome?

A group of ecosystems that share a climate and hence sustain similar communities.

Why do different communities in the same biome evolve similar traits?

They share common abiotic factors and selection pressures, leading to convergent evolution.

What evolutionary process causes unrelated species in similar biomes to develop similar adaptations?

Convergent evolution

Which syllabus code addresses 'Biomes as ecosystems with similar communities due to similar abiotic factors and convergent evolution'?

B4.1.7

List the six main types of biomes described in the lecture notes.

Hot Desert, Grassland (savannah), Temperate Forest, Tropical Rainforest, Taiga (Boreal), and Tundra.

What are the temperature and rainfall characteristics of a Hot Desert biome?

Temperature: Extreme; Rainfall: Very low.

What are the productivity and biodiversity levels of a Hot Desert biome?

Productivity: Very low; Biodiversity: Very low.

What are the temperature and rainfall characteristics of a Grassland biome?

Temperature: Moderate; Rainfall: Fluctuates.

What are the productivity and biodiversity levels of a Grassland biome?

Productivity: Low; Biodiversity: Low.

What are the temperature and rainfall characteristics of a Temperate Forest biome?

Temperature: Seasonal; Rainfall: High.

What are the productivity and biodiversity levels of a Temperate Forest biome?

Productivity: Seasonal; Biodiversity: High.

What are the temperature and rainfall characteristics of a Tropical Rainforest biome?

Temperature: Warm; Rainfall: Very high.

What are the productivity and biodiversity levels of a Tropical Rainforest biome?

Productivity: High; Biodiversity: Very high.

What are the temperature and rainfall characteristics of a Taiga (Boreal Forest) biome?

Temperature: Cold; Rainfall: Low (snow).

What are the productivity and biodiversity levels of a Taiga (Boreal Forest) biome?

Productivity: Low; Biodiversity: Low.

What are the temperature and rainfall characteristics of a Tundra biome?

Temperature: Very low; Rainfall: Low (snow).

What are the productivity and biodiversity levels of a Tundra biome?

Productivity: Very low; Biodiversity: Very low.

Which biome features seasonal temperatures, high rainfall, seasonal productivity, and high biodiversity?

Temperate Forest

Which biome features warm temperatures, very high rainfall, high productivity, and very high biodiversity?

Tropical Rainforest

Which biome features cold temperatures, low precipitation as snow, low productivity, and low biodiversity?

Taiga (Boreal Forest)

What is a climograph?

A diagram that illustrates biome distribution based on precipitation and temperature patterns.

On a climograph, what variable is plotted on the Y-axis?

Precipitation (annual rainfall in cm)

On a climograph, what variable is plotted on the X-axis?

Average temperature ($^\circ\text{C}$)

According to a climograph, what biome develops in regions with hot temperatures and dry, low precipitation?

Desert

According to a climograph, what biome develops in regions with hot temperatures and very wet, high precipitation?

Tropical Forest (Tropical Rainforest)

According to a climograph, what biome develops under cold, icy conditions with low precipitation?

Tundra

Which syllabus code covers 'Abiotic factors as the determinants of terrestrial biome distribution'?

B4.1.6

Look at this climograph. Which biome occupies the highest region along the precipitation Y-axis?

Tropical Forest

What abiotic challenges characterize sand dune environments?

Loosely-packed sediment with reduced nutrient levels and low water availability.

What abiotic conditions characterize swamp environments?

Waterlogged soils with low oxygen availability and high levels of salinity.

What abiotic challenges characterize desert environments?

Low levels of rainfall (dry and arid) and extreme temperatures (hot during daytime).

What abiotic challenges characterize tropical rainforest environments?

Dense vegetation (restricting light availability) and high levels of biodiversity.

Which grass species is specifically adapted to thrive on sand dunes?

Marram grass

How do horizontal underground stems (rhizomes) adapt marram grass to sand dunes?

They maximize root penetration and stabilize the plant in shifting sand.

Why does marram grass possess an extensive root system?

To improve anchorage and access reservoirs of underground water.

How do curled leaves benefit marram grass in windy dune habitats?

They reduce the exposure of stomata to external air, decreasing transpiration water loss.

Look at this microscopic cross-section of a leaf. What is the structural adaptation where stomata are located inside leaf folds?

Stomata sunk in pits (to trap water vapour in marram grass).

Which tree species is specifically adapted to survive in swamp habitats?

Mangroves

Look at this image of mangrove roots growing above waterlogged soil. What is the main function of these aerial roots?

To take in oxygen from air for cellular respiration in waterlogged soil.

What are plants adapted to saline (salty) conditions called?

Halophytes

How do mangroves handle high intracellular salt concentrations?

They sequester salts in cell walls or vacuoles to minimize osmotic disruptions.

How do some mangroves discard excess salt via leaf shedding?

They concentrate salts in particular leaves, which are then shed via abscission.

How do deep tap roots in mangroves aid in salt management?

They are structured to exclude salt uptake from soil water.

What term describes plants adapted to arid, low-water desert environments?

Xerophytes

Look at this desert plant. What xerophytic cactus example is cited in the lecture notes?

Saguara cactus