This document provides information about different animal groups found in the environment. It classifies animals into two main subgroups - vertebrates and invertebrates. Vertebrates make up 2% of animals and have backbones, while invertebrates comprise 98% and do not have backbones. Vertebrates are further divided into five classes - fish, amphibians, reptiles, birds, and mammals. Invertebrates include groups like protozoans, poriferans, coelenterates, platyhelminths, nematodes, annelids, echinoderms, mollusks, and arthropods. Each group is characterized and examples are provided.

1. ANIMALS IN THE
ENVIRONMENT

2. ANIMALS
• Classify into two subgroups: Vertebrates and Invertebrates. Earth consists of a
variety of animals from simple to the most complex groups.
• Both subgroups belong to chordates – group of animals with notochord or a
flexible rod of cells inside their bodies.
• Invertebrates – comprises of 98% of animals in the world. They can be found in a
vast range of habitats such as forests, deserts, caves, and seabeds. They have
nervous system that helps them to respond to the environment through their
instincts. Ex: jellyfish – has nerve net that contains receptors of stimuli such as
physical contact, food, and chemicals. A light touch with its cilium or its organ for
locomotion, provides information for muscle movement.
• Vertebrates – made up of 2% of animals, the higher form of animals. They have
internal skeletons made up of bones that give them shape. They have large and
more developed brains enclosed in skulls.

3. VERTEBRATES
C l a s s i f i e d t h e m i n t o f i v e s m a l l g r o u p s : f i s h ,
a m p h i b i a n s , r e p t i l e s , b i r d s , a n d a n i m a l s .

4. FISH
• Aquatic animals that breathe through gills
• Have skeletons made of either bones or cartilages
• Classified:
 bony fish – have a swim bladder, a gas-filled sac that allows them
to rise or sink in the water.
 cartilaginous fish – must swim to keep afloat, and has spindled-
shaped bodies and tail fins that are used in swimming. They are also
covered with scales and are cold-blooded (means that their body
temperature changes and becomes the same as the temperature around
them.

5. BONY FISH – milkfish,
tilapia, mudfish, and catfish
CARTILAGINOUS FISH –
SHARKS AND STINGRAYS

6. • Fishes like milkfish, tilapia, mudfish, catfish, and salmon are sources of
food.
• Sharks and codfish are sources of oil that is rich in Vitamin A and D.
• Fishes with attractive colors and shapes are kept in aquarium as pets.

7. AMPHIBIANS
• Cold-blooded vertebrates, covered with moist skin, and they lay eggs in
water, and also have three-chambered heart.
• Example: frogs, salamander, and newts.
• They are useful animals.
• Certain species of frogs are edible, their hind legs are eaten as delicacy
by some people. Also used as specimens, which are dissected in
laboratories to study the organ system of animals.
• Bullfrogs or heavy-bodied frogs, help protect farm crops by feeding on
insects and worms in the fields.
• Newts and salamander feed on insects and other pests too.

9. REPTILES
• Cold-blooded animals that are covered with scales. Their bodies react to
the temperature of their surroundings. When they get too warm, they
go into the water or under a shade to cool off. When they get cold, they
hang out under the sun to warm themselves up.
• Common reptiles are: alligator, crocodiles, lizards, snakes, turtles,
tortoises, geckos, and iguanas. They have dry and scaly skins that cover
the body, breathe through lungs, and certain reptiles may live not only
on land but also in water, and lay their eggs on dry land.

10. • Crocodiles and alligators – good swimmers,
• Sea turtles and tortoises – have protective shells, have strong, sharp
beaks and well-known fro their long life span
• Snakes and lizards – shed its skin coverings, have abdominal scales
called scutes.
• Lizards – have four-legged with five-clawed toes on each foot
• Chameleons – lizards that can change their skin color to math the
surroundings
• Certain reptiles are dangerous:
– Snakes – have jaws that can swallow their prey, have fangs that can inject
poison to their victims
– Crocodiles and alligators – very strong and can inflict harm to people
– Lizards – useful as they eat harmful insects

12. BIRDS
• Warm-blooded means they keep their bodies temperature no matter
what the temperature is around them.
• Bodies are spindle-shaped and are covered with feathers. They have
wings, hollow bones, and thin skulls, all of which make their bodies
extremely light for flying. They breathe though their wings.
• Birds how they adapt to their environment:
Ostrich – use their wings to keep them blance as it runs 70 kph using its
long legs
Herons, ducks, and geese – use their feet for paddling and swimming
 eagles, parrots, and hawks – used their claws or talons for grasping their
prey

13. Sparrows and parrots – use their beaks to gather food, build their nests, feed
their young, and eat.
Low flying chickens, turkeys, quails, and peacocks – use their claws to scratch
the ground to look for food.
• Birds help in many ways:
- Meats and eggs can be eaten
- Ducks, chickens, and turkeys are important food for humans
- Help farmer to feed on harmful insects and worms that damage food crops
- Some people enjoy keeping birds as pets at home.

15. MAMMALS
• Warm-blooded animals, have hairy bodies. Mother mammals retain their
young in their bodies until they are ready to be born.
• Mothers feed young ones with milk through its mammary glands or
milk-secreting glands.
• Example of mammals:
- Primates
- Marsupials
- Rodents
- Cetaceans
- seals

16. PRIMATES• Highest order of mammals
• Have well-developed brains, hands,
and feet with nails, and eyes that face
forward
• Interact with their own kinds
• Ex: orangutans, monkeys, gorillas,
chimpanzees, and baboons.
• Humans are also primates. Their
brains more than twice the size of
those of other primates. Humans are
the most intelligent primates with the
most developed communication and
reasoning skills, and also walk upright
using two legs.

17. MARSUPIALS
• Mammals that give birth to tiny
helpless living young that crawl into
special abdominal pouch near the
mother’s mammary glands.
• Ex: koalas, wallabies, and kangaroos
• Newborn babies suck milk until hey
are big enough to be weaned, or
allowed to leave their mother’s
abdominal pouches.
• Most of them found in Australia and
other islands in South Pacific Ocean.

18. RODENTS
• Also called gnawing animals because of the
way they eat with their large incisors.
• Ex: squirrels, porcupines, chipmunks, and
beavers – North America; rabbits, hares, and
mice,
• Squirrels – have agile and flexible bodies,
string hind limbs, and bushy tails enable
them to climb up and live in trees, have four
big front teeth adapted for gnawing nuts and
seeds
• Porcupines – covered with black or brown
barbed spines and stiff hair used against
predators. They feed on plants-twigs, leaves,
and green plants.
• Chipmunks – small squirrel-like animal that
eat nuts, berries, seeds, and grains, which is
temporarily carried in its cheek pouches and

19. • Hares – similar to rabbits except their ears are longer usually with black
markings, and they have more prominent long hind legs, which they use
to move and run so swiftly to escape their enemies. They eat hard bark,
twigs, buds, and shoots.
• Mice – with pointed snout and small round ears, have poor eyesight but
a keen sense of hearing and smelling that they use to find food, and
they destroy crops, damage structures, and spread diseases through
their parasites and feces.
• Rabbits – herbivore rodents that are generally small and chubby. They
are social animals that they tend to share burrows with other animals.
They prefer softer food like grass and vegetables.

20. CETACEANS
• Mostly marine animals such as
whales, dolphins, and porpoises. Live
in water but they must come to the
surface to breathe air through their
blowholes or the nostrils on top of
their heads.

21. INVERTEBRATES
A n i m a l s t h a t a r e l o w e r i n f o r m t h a n
v e r t e b r a t e s b e c a u s e t h e y d o n o t h a v e
b a c k b o n e , t h a t i s , t h e y d o n o t h a v e i n t e r n a l
s k e l e t o n . I t i s c l a s s i f i e d i n t o 9 g r o u p s .

22. PROTOZOANS
• Simple, microscopic, and single-celled animals.
• too small to be seen with the naked eyes. They move, breathe, and
reproduce.
• Certain protozoans live in stagnant freshwater ponds, soil, and decaying
matter.
• They are the food sources of fish and other animals. Helpful also because
they eat dangerous bacteria.
• They can also be harmful because they can transmit diseases, such as
amoebiasis and giardiasis (intestines), also causes sleeping sickness.
• Ex: amoeba, paramecium, and euglena

23. Amoeba
- Clear shapeless cell
- Move slowly using its
pseudopodia or false
feet. It is also used to
engulf food.
Paramecium
- slipper-shaped
protozoan, that moves
with the use of cilia or
short hair-like
projections.
- Cilia works as paddles
through the water and
sweep food into its long
mouth-like opening.
Euglena
- cylindrical-shaped
protozoan that has a
flagellum or a whiplike
extension used for
movement.
- Flagellum is longer than
the cilia.

24. PORIFERANS
• Pore-bearing animals
• The bodies are thick-walled bags with pores that serve as the entrance of
water that carries the food materials.
• It appears in different colors – white, red, orange, yellow, green, and brown.
• Ex: sponges
– Vary in shape and size, form into flat, colorful mats in shallow water, also grow
tall and upright like a vase in deep and still waters.
– Some sponges has soft framework made of rubberlike spongin a protein fiber.
– Other sponges have framework of hard spikelike spicules (calcium carbonate or
silica)
– The sponge used for bathing and washing is the skeleton of one of the sponges
– Feed on very fine particles suspended in the water such as bacteria,
dinoflagellates, and other small plankton or tiny organism that cannot swim but
just drift in the water.

26. COELENTERATES
• or cnidarians are radially symmetrical animals with tentacles around their
mouth.
• Ex: jellyfish and hydra
• Jellyfish
– Hollow umbrella-shaped bags, tentacles sting other animals and inject
poisonous substance, have mouth and tentacles that are directed downward
but move upward, tentacles used for movement and to capture food
• Hydra
– Slender cylindrical body with threadlike tentacles around the mouth that are
used to catch prey, stays on most unpolluted freshwater ponds, lakes, and
streams

28. COELENTERATES
• Corals are also cnidarian
– Feed on tiny floating organisms called zooplanktons
– When die, skeletons remain and form coral reefs or rocklike structures in
tropical seas

29. PLATYHELMINTHS
• have long, flat, and ribbonlike bodies.
• They are parasitic, live on intestines and feed on the
digested food of their hosts
• Ex: flukes, tapeworms, and planarians

30. Fluke
- Worm invades in the liver,
bile duct, gallbladder,
intestine, or lung of certain
animals
- Parasite feed on blood and
produces eggs in the infested
organs,
- Infections occur after eating
fluke-infested raw or
undercooked fish or meat
Tapeworm
- Infest intestines of humans
and other vertebrates
- Gets into the body through
eating and drinking infected
with the worm’s larvae or eggs
- Feed on the food that host is
digesting
Planarian
- Simplest flatworm found in
freshwater or saltwater
- Maybe black, brown, gray, or
white
- Feeds on crustaceans and
other small worms

31. NEMATODES
• Round worm and considered parasites
• Taking in contaminated food and water, children play
barefoot can easily acquire the larvae of nematodes,
larvae enter through the skin of the feet
• Ex: ascarides, filarial worms, and hookworms

32. Ascarides/ascaris
- round, elongated, and
cylindrical intestinal worm
that infects human
- Adult ascarides (creamy white
or pinkish in color), male
ascarides (slender and
shorter than female)
- Reside in the intestines of
humans, leading to a
condition known as
ascariasis (infection on the
liningof the intestines)
- Ingested through
contaminated raw food or
soil particles
Filarial worm
- Small threadlike roundworms
carred as larvae by mosquitoes
and other biting insects
- Enters the skin and develops
in the lymphatic vessels
- Person infected develop tissue
swelling or elephantiasis –
enlargement of the limbs and
male genitals
Hookworms
- Grayish white or pinkish
roundworms with slightly bent
and hook-shaped heads
- Female hookworms are often
longer and stouter than male
- Infect humans by damaging
the lining of the intestines and
sucking
- Larvae penetrate the skin and
go to the small intestine,
nutrients of the human body
nourish the hookworms

33. ANNELIDS
• Have long cylindrical bodies that are divided into segments
• Ex:
• Leeches
– Parasitic segmented worms known as blood suckers (feed on blood from
animals)
– Have suckers at each end of the body,,
– Flattened and dark in color, often black or dark green
– Live in shallow, slow-moving freshwater, but certain leeches live in the ocean
and in moist soil.
• Earthworm – tubelike, segmented annelids that are found in the soil
– Burrows at night, hence, called as night crawler
– Its waste makes the soil fertile

34. ECHINODERMS
• Marine invertebrates with spines
• Use spine for protection against predators
• Have tube feet or podia with suckers that are used to move along a
substrate
• Have exoskeleton or external hard supporting structure
• Can reproduce new form from its detached part
• Ex: starfish  used specimen in science classes
– Sea urchins  with movable spine that is poisonous
– Sea cucumber  grow underwater, and feed on algae and tiny aquatic
animals
– Sea lilies  mouth located at the center and have five or more feathery

36. MOLLUSKS
• Animals with soft fleshy bodies that are usually covered by shells
• Divided into 3 groups:
– Univalves  covered by one piece of shell, ex: slugs and snails
– Bivalves  covered with two pieces of shells, ex: clams, mussels, and oysters
– Head-footed mollusks  body is not covered by shell, ex: squids and
octopuses

40. ANTHROPODS
• Characterized by segmented chitinous exoskeleton and jointed appendages
• Includes insects, crustaceans, arachnids, and myriapods
• Insects – have three paired of legs, one or two pair(s) of wings, and a pair of antennae
– Made up of head, thorax, and abdomen
– Ex: flies, ants, butterflies, beetles, crickets, cockroaches, and mosquitos
• Crustaceans – live mostly in the ocean
– Possess 5 pairs of legs, a pair of pincers, and an external shell that protects their
body
– Ex: crabs, shrimps, lobsters, barnacles, and prawns
• Arachnids – have 4 pair of legs, their head and thorax are in single prosoma or
anterior part of the body
– Ex: spiders, scorpions, ticks, and mites

41. MOLLUSKS
– Spiders have spinnerets or the organs used to spin silk threads for webs and
silk sacs
– Ticks and mites are disease-transmitting parasites that live on blood of other
animals
– Scorpions have stingers that have poison that can cause pain or even death
• Myriapods – with many legs
– Ex: centipedes and millipedes
– Centipedes have a pair of legs in every segment of their bodies, have long
flat bodies with antennae and poisonous claws
– Millipedes is similar to centipedes, each segments has two pairs of legs,
move slower than centipedes, and feed on young plants or decaying plant
matter