Transcript Topic 5.5 Notes - mrs

Unit 5
Fresh and Saltwater
Systems
Topic 5
Living in Water
Read: Pages 432 - 447
Remember to name and date your
• Lakes and ponds are bodies
of fresh water that collect in
low areas of land.
• Remember – a pond is small,
shallow, and light can hit the
bottom.
• Plants can grow at the
bottom of a pond.
• Lake is usually larger than a
pond.
• Plants cannot grow on the
bottom of a lake…except
along shorline.
• Rivers and streams are
usually shallow and contain
sediments eroded from land.
• Most animals who live in
rivers and streams must
attach themselves to rocks
or plants (or be good
swimmers) as the rivers are
always moving.
• Oceans are salty, deeper, and
move more due to tides,
currents, and waves.
• Most marine organisms are
found in the top 180m of
water. (average depth to
which light can penetrate.)
• Most marine organisms live
on the continental shelf as
this is where plants can
grow.
• 90% of marine life occurs
here.
• Most aquatic animals use
gills to extract oxygen from
water.
• Marine mammals (whales,
sea lions) use lungs.
• Some marine life tuck
themselves under rocks,
bury themselves in sand, or
suction themselves to avoid
being swept away.
• Larger marine life, like fish
and whales, are shaped to
move easily through water.
• Plankton (zooplankton –
animal plankton, and
phytoplankton – plant
plankton) float on currents.
• Food for marine life.
• Some marine life capture
food and eat it.
• Others filter food out of the
water. Great whales filter
plankton out of the water
using baleen.
Aquatic Plants
• Two types: those attached to
the bottom and those that
float.
• Where is plant life found?
• Attached plants: plants in
shallow water often have
roots – get nutrients from
soil.
• Many plants have long open
channels in their stems to
carry oxygen to the roots.
• Marine plants have stomata
on top of their leaves so that
floating leaves can get
oxygen.
• Flexible stems allow plants
to move with currents and
waves. They are supported
by water around them.
• Seaweed does not have
roots, flowers, or leaves.
• Photosynthesize for food.
• Use a holdfast to attach to
bottom.
• Get nutrients from water.
• Phytoplankton: 0.002 mm to
2mm in size.
• Much of marine life depends
on them for food.
• Stay in upper or surface to
get sunlight to
photosynthesize.
• Aquatic plants need nutrients
like nitrates and phosphates.
• Washed into water from land
or come from detritus –
decaying bodies of dead
plants and animals.
• Nutrients plentiful in spring
from runoff and melting.
• Human wastes, fertilizers and
pollution sometimes cause
too many nutrients in water.
• Causes growth of algae –
another aquatic plant.
• An algae explosion, called an
algae bloom can occur.
• When algae die they fall to
the bottom of water where
they are decomposed by
bacteria.
• Decomposition require
oxygen – and oxygen from
the habitat can be used up,
killing plants and animals.
Aquatic Food Chains
• A sequence of feeding
relationships between
organisms.
• Fishing can affect food
chains.
• Fisheries catch larger and
most in demand fish. Their
population can fall.
• Other populations of fish
may also decrease, or even
increase as a result.