Habitats Video Lecture | AP Biology - Grade 9

picture of polar bear in the desert know
what you're imagining is way too cute
take off the sunglasses and the swim
trunks there he's hot he's hungry he's
downright miserable why is he such a
grumpy bear well it's because he's not
where he belongs
there aren't any tasty seals to eat no
cold water to enjoy and no snow to sleep
in the desert isn't his habitat you know
that a habitat is the area where
something lives but from polar bears to
porcupines animals don't just need a
place to live they also rely on the
other living and nonliving things around
them to survive and life looks different
in different places around the world so
what makes a habitat a home well what do
you need I need sandwiches pancakes
carrots maybe some nice peaches so I
need food and I need water I need a
place to live and I need a place to film
crash course videos you could say this
is my habitat animals need these things
to food water shelter and space to live
for animals their food comes from their
neighbors the other living things in
their habitat you know that plants and
animals all fall somewhere along the
food chain which is a model we use to
describe the flow of energy between
living things but the real world is made
up of lots and lots of food chains and
those chains can get kind of messy I
mean look at our polar bear sure his
favorite food is seal but in a pinch
he'll eat walrus dead whales birds eggs
and if he has absolutely no other choice
plants the polar bear is at the top of
multiple food chains and that's not
unusual most animals don't just eat one
thing and neither do i I'm at the top of
the pancake food chain and the carrot
food chain it just so happens I prefer
pancakes so you can see how food chains
are actually all tangled around with
each other with many different ones
overlapping kind of like a web so we
call this a food web food webs are big
tangled systems that include every plant
and animal in a habitat and as you might
guess all food webs are different let's
compare two different habitats to see
how the food webs play out
hmm first we'll go back to our old
stomping ground the forest let's begin
with you know this people the plants
trees grass and other plants that change
energy from the Sun into sugar but then
you have some animals that eat other
animals this is where things get a
little more complicated today an owl
makes a mouse his lunch but tomorrow it
may be a rabbit today a snake snacks on
a squirrel but a few days later our our
friend might make a meal of another
meat-eater like the snake finally the
decomposers insects fungi and bacteria
are breaking down whatever is left over
from uneaten rotten fruit - leftover
animal carcasses as they break down
matter they provide more nutrients for
the plants it's a bit of a different
story up in the Arctic I mean look at
all that ice I know what you're thinking
where are the plants how do we have a
food web without plants zoom in on the
seawater zoom way in further further
stop can you see those tiny plants
they're called phytoplankton and just
like plants on land they convert energy
from the Sun really small creatures
called ZOA plankton eat the
phytoplankton in all kinds of small fish
dying on the ZOA plankton larger fish
eat the smaller fish there are big
marine mammals - beluga whales eat fish
while humpback whales eat the tiny
plankton and krill and what else eats
fish seals that's our polar bears
favorite food but up here you can't
afford to be picky so we may have to
nibble on some whale carcass if
necessary as for decomposers there
aren't many bugs or earthworms in this
cold climate there are bacteria but
since it's so cold the decomposers break
down matter much more slowly than in the
forest
so you can see food webs and the
ecosystems that support them look
different in different parts of the
world depending on the habitat
conditions flat or mountainous land more
or less water these seemingly small
changes and habitats affect what kind of
plants and animals live there up in the
Arctic a polar bear has the right
conditions to keep him happy
first he fits into his food web
perfectly the food that's available to
him has enough fat and protein to keep
his energy up second he fits into his
habitat perfectly he has the body
adaptations to not just survive but feel
really comfortable in the super cold a
polar bear isn't built to survive in the
desert or the forest so let's put our
poor polar bear back where he belongs I
was starting to feel bad for the guy
Oh