Transcript Powerpoint

Chapter 12
The Marine Habitat
Essentials of Oceanography
7th Edition
The diversity of marine life
The ocean is home to a wide variety of
organisms
Marine organisms range from microscopic
bacteria and algae to the largest animal in
the world (blue whale)
Number of known marine species: 250,000
Classification of living things
Organisms can
be classified into
one of three
domains of life:
Archaea
Bacteria
Eukarya
Figure 12-1
Classification of living things
Organisms can
also be classified
into one of five
kingdoms:
Monera
Protoctista
Fungi
Plantae
Animalia
Figure 12-1
Classification of living things
Taxonomic classification includes the
following increasingly specific groupings:
Kingdom
Phylum (Division for plants)
Class
Order
Family
Genus
Species
Taxonomic classification of
selected organisms
Category
Human
Killer whale
Giant kelp
Kingdom
Phylum
Subphylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Vertebrata
Mammalia
Primates
Hominidae
Homo
sapiens
Animalia
Chordata
Vertebrata
Mammalia
Cetacea
Delphinidae
Orcinus
orca
Protoctista
Phaeophyta
Phaeophycae
Laminariales
Lessoniaceae
Macrocystis
pyrifera
Classification of marine
organisms
Marine organisms can be classified into
one of three groups based on habitat and
mobility:
1.
Plankton (floaters)
Phytoplankton (drifting plants and algae)
Zooplankton (drifting animals)
Nekton (swimmers)
3. Benthos (bottom dwellers)
2.
Plankton: Examples
Phytoplankton
Zooplankton
Figure 12-2
Nekton: Examples
Figure 12-4
Benthos: Examples
Figure 12-5
Life cycle of a squid
Squid experience
benthic, planktonic,
and nektonic stages
Squid are
considered
meroplankton
(opposite =
holoplankton)
Figure 12-3
Distribution of species on Earth
The land has more
species because it has
greater environmental
variability than the ocean
Most ocean species are
benthic because of greater
environmental variability
compared to pelagic
environments
Figure 12-6
Adaptations of organisms to the
marine environment
The marine environment presents many challenges
to organisms because seawater:
Is dense enough to support organisms
Has high viscosity
Experiences variations in temperature and salinity
Contains variable amounts of dissolved gases
Has high transparency
Has a dramatic change of pressure with depth
Marine organisms have various adaptations for the
conditions of the marine environment
Need for physical support
Condition:
Seawater is dense enough to support marine
organisms
Adaptations:
Many marine organisms lack rigid skeletons,
appendages, or vast root systems
Instead, they rely on buoyancy and friction to
maintain their position within the water column
Seawater’s viscosity controlled
by temperature
Condition:
Seawater’s viscosity (resistance to flow) is
strongly affected by temperature
Cold water has higher viscosity than warm
water, so is more difficult to swim through
Warm water has lower viscosity, so organisms
tend to sink within the water column
Seawater’s viscosity controlled
by temperature
Adaptations:
Many warmwater organisms
have ornate
appendages to
say afloat
Many cold-water
organisms are
streamlined to
swim more easily
Warm-water
copepod
Cold-water
copepod
Figure 12-7
Seawater’s viscosity and
adaptations of phytoplankton
Condition:
Phytoplankton must remain in
sunlit surface waters
Adaptations:
Small size increases surface
area to volume ratio
Appendages increase
frictional resistance
Tiny droplet of low density oil
increases buoyancy
Figure 12-8
Variations in temperature
Condition:
Coastal water temperatures vary more than the
open ocean or at depth
Adaptations:
Many coastal organisms can withstand a wide
temperature range (are eurythermal)
Most open ocean and deep-water organisms can
withstand only a small temperature range (are
stenothermal)
Variations in salinity
Condition:
Coastal environments experience greater salinity
variation than the open ocean or at depth
Adaptations:
Many shallow-water coastal organisms can
withstand a wide salinity range (are euryhaline)
Most open ocean and deep-water organisms can
withstand only a small change in salinity (are
stenohaline)
Osmosis
Condition:
Osmosis is the movement
of water molecules
through a semipermeable
membrane from higher to
lower concentrations
Osmosis removes water
from hypotonic organisms
Osmosis adds water to
hypertonic organisms
Figure 12-13
Osmosis
Adaptations:
Figure 12-14
Dissolved gases: Oxygen
Condition:
Marine animals need
oxygen to survive
Adaptations:
Many marine animals
use gills to extract
dissolved oxygen from
seawater
Marine mammals must
breathe air
Figure 12-15
Abundance of dissolved oxygen
and nutrients with depth
Figure 12-20
Seawater’s high transparency
Condition:
Camouflage
Seawater has high
transparency
Adaptations:
Transparency
Camouflage
Countershading
Migration (DSL)
Countershading
Figure 12-17
The deep scattering layer (DSL)
Organisms
within the deep
scattering layer
undertake a
daily migration
to hide in deep,
darker waters
during daytime
Figure 12B
Increase of pressure with depth
Condition:
Pressure increases rapidly with depth
Adaptations:
Most marine organisms lack large compressible
air pockets inside their bodies
Water-filled bodies exert the same amount of
pressure as is pushing inward, so marine
organisms do not feel the high pressure at depth
Divisions of the marine environment
Main
divisions:
Pelagic
(open sea)
Benthic
(sea
bottom)
Figure 12-19
End of Chapter 12
Essentials of Oceanography
7th Edition