where is biodiversity ? Flashcards

Lecture 3 - John Spicer (27 cards)

1
Q

species-area relationship

principle pattern

A

as size of geographical area increases so to does the number of species

practical use - predict that as area is reduced, tend to lose species

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2
Q

habitat loss / fragmentation

A

major determinant of modern extinctions

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3
Q

sea/land phyla

A

all animal phyla ( approx 34 ) occur in the sea (one exception - velvet worms (onychophora))

two thirds ( 20 ) almost exclusively marine

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4
Q

marine phyla

A

98 % live in/on the sea floor ( = BENTHIC )

2 % live floating or swimming in the sea ( = PELAGIC )

only 15% of named species are marine

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5
Q

photosynthesis - sea/land comparason

A

sea : very few, large photosynthetic organisms - mainly short lived, microscopic algae

land : dominated by persistant long lived ‘large’ flowering plants

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6
Q

herbivoress - sea/land comparason

A

sea : dominant herbivores - micro (copepods) majority of large animals carnivorous

land : dominant herbivores can be large

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7
Q

grazing - sea/land comparason

A

sea : grazing - ingestion of entire autotroph

land : grazing - rarely removes significant amounts of communities ( indigestible e.g wood )

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8
Q

autotroph

A

an organism that can produce its own food using light, water, carbon dioxide, or other chemicals

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9
Q

food chain - sea/land comparason

A

sea : food chain average 5 links

land : food chain average 3 links

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10
Q

abyssal

A

depths od ocean between 4000-6000m deep

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11
Q

bathyal

A

relating to the zone of the sea between the continental shelf and the abyssal zone (depths 1000 - 4000m)

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12
Q

hadal

A

relating to the zone of the sea greater than 6000 m in depth chiefly oceanic trenches

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13
Q

littoral

A

area of shoreline where land is subject to wave action

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14
Q

sublittoral

A

living, growing, or accumulating near to or just below the shore

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15
Q

endemic species

A

plants and animals that exist only in one geographic region

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16
Q

Alexander Von humboldt

A

latitude - 1799 onwards

Venezuela - Mexico : species identity differs with latitude

17
Q

Alfred Russel Wallace

A

number os species increases as you go from temperate to tropical regions

18
Q

planktonic diversity

A
  • all 3 domains of life
  • overall decline in diversity towards the poles ( saame pattern as on land )
  • driven by decresing water temperatures
19
Q

species richness

A

the number of species within a defined region

20
Q

shallow water - species richness

A
  • coastal marine fish/bacteria - increase in species richness towards the equator
  • coral reef fish - no pattern
  • amphipods/isopods/bivalves - highest before reach the equator
21
Q

deep sea - species richness

A
  • increase in richness towards the equator for number of taxa of bivalves, gastropods and isopods
  • forminiferans - highest before reach the equator ( single celled protists - very simple microorganisms )
22
Q

pelagic - species richness

A
  • increase in richness towards the equator - ostracods, euphausiids (krill), shrimp, fish (N. hemisphere), bacteria,
23
Q

elevation

A

Von Humboldt - number and type of plant species changed as ascended volcano

species richness decreases with increasing elevation

24
Q

life below Earth’s surface

A

endemic cave communities
- chemosynthetic ecosytem (chemosynthesis is the process by which certain microbes create energy by mediating chemical reactions)

25
azoic zone hypothesis
Edward Forbes there was zero life below the azoic zone (550m) hypothesis was short lived
26
depth : species richness
species richness decreases with depth
27
depth ( species richness )
- overall decrease in species richness with increasing depth - diversity peaks at intermediate depths ( 0.3 - 4.7 km ) - pelagic peak - more shallow than benthic - pressure and temperatire thought to limit species richness