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Flashcards in The Critical Zone Deck (25)
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1
Q

What is the biosphere?

A
  • The biologically inhabited part of the earth
  • Deep oceans to atmosphere
  • Interacts with lithosphere (geology), hydrosphere and atmosphere
2
Q

What is biogeography?

A

Branch of geography which explores patters - why are organisms where they are?

3
Q

What is historical biogeography?

A
  • Looks at reconstructing the origin, dispersal and extinction of species or taxonomic groups
4
Q

What is ecological biogeography?

A
  • Looks at present distributions and geographic variations in diversity, environmental constraints on species distribution and how biotic and abiotic interactions influence species distribution
5
Q

What happens in the critical zone?

A
  • All activities and resources that sustain human life
  • Food and fuel production
  • Biological gene pool
  • Carbon storage
  • Clean water and soil
6
Q

What is species distribution a result of?

A

A result of multiple biotic and abiotic drivers

7
Q

What are the biotic factors which drive species distribution?

A
  • Influence of ecosystem engineers (humans, beavers)
  • Interacting among species - competition
  • Individual response of species - extinction
8
Q

What are the abiotic factors which drive species distribution?

A
  • Geographic template
  • Temporal dynamics of the geographic template - tectonics, sea level change, climate change
  • processes occurring on geological timescales results in temporal patterns of species distribution
9
Q

What are the biological drivers of biotic factors?

A
  • Some biota may respond to environmental variation - adaptation, evolution, dispersal or extinction
  • Some species act as ecosystem engineers and alter the physical environment
10
Q

What are the four main processes regulating biogeographical patterns and species distribution?

A

1) Abiotic processes - physical environment that is external to organism
2) Physiological processes - how a species adapts and evolves
3) Biotic interactions - symbiosis, mutualism and parasitism
4) Historic events - how did a species get there - invasive

11
Q

What is the natural world described as?

A
  • A series of biogeographic units

- Allows a collective description of processes and structures

12
Q

What are the different scales of the natural world?

A
  • Biome - global/continental spatial scale

- Ecosystem - a community of organisms and its environment in one unit

13
Q

What is a biome?

A
  • Biological meta communities
  • Similar but unconnected regions
  • Two master variables - temp and precipitation
  • Collections of areas with similar a biotic factors that produce similar ecological communities
14
Q

What are the biome characteristics of a tropical rainforest?

A
  • Dominated by broad-leaved evergreen species
  • High biodiversity
  • Hot and wet
  • Poor, thin soil
  • evolution was not disrupted by glaciation
  • High productivity - range of resources
15
Q

What are the characteristics of a savannah grassland biome?

A
  • Grasslands with low density trees and shrubs
  • Support Hugh number of herbivores, large grazing mammals
  • Warm/hot climate
  • Rainfall - 6/8 months
  • Maintained through droughts and fires
  • Shallow soil
16
Q

What are the characteristics of the desert biome?

A
  • Hot and dry
  • Covers 1/5 of earths surface
  • Specialised flora and fauna
  • Less than 50cm/year of rain
  • Soils are nutrient rich
  • Low plants, small thick leaves
17
Q

What are the characteristics of a temperate deciduous forest biome?

A
  • Broad leaved deciduous trees
  • Less dense, shorter forests
  • Few dominant species
  • High rainfall
  • Rich soils
18
Q

What are the characteristics of a temperate grassland biome?

A
  • Mostly grasses
  • Steppes and praises
  • Some trees
  • Grazed by large mammals
  • Deep nutrient rich soil
19
Q

What are the characteristics of a tundra biome?

A
  • Low biotic diversity
  • Artic shrubs mosses, grasses and lichen
  • Alpine dwarf trees, shrubs and grasses
  • simple vegetation structure
  • Low temp and no rain
  • Poor nutrient soils
20
Q

Define ecosystem structure

A

Biotic and abiotic components or attributes within an ecosystem

21
Q

What are the two most important functions in an ecosystem?

A

Energy and nutrient cycling

22
Q

What is energy and nutrient cycling controlled by?

A
  • Producers
  • Consumers
  • Decomposers
  • Water cycle
23
Q

What is primary production?

A
  • Generation of biological material by plants – photosynthesis
  • Key process -conversion of inorganic carbon dioxide to organic carbon
  • Autotrophs – self feeders
  • Not often at equilibrium
24
Q

What cause an ecosystem to change?

A
  • Changes in structure
  • Relative species abundances
  • Species immigration/emigration (local extinction)
  • Feedback to changing abiotic conditions such as soil fertility, microclimate
  • Does not mean ecosystem is not stable
25
Q

What is succession?

A
  • Disturbances destroy existing habitats and create new ones
  • These are then colonised by species, creating new ecosystems
  • Colonisation of bare ground is called primary succession
  • Secondary succession occurs when existing vegetation is removed