LIFE SCIENCE
Objective 4.1
(8 Questions)
Classify animals according to type of skeletal structure, method of fertilization and reproduction, body symmetry, body coverings, and locomotion.
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Core Concept
Sponges are invertebrate animals that usually have no body symmetry and never have body tissues or organs. They are
filter feeders that are able to reproduce both sexually, utilizing external fertilization, as well as asexually utilizing
budding. Sponges belong to the phylum Porifera. Adult sponges are not able to move.
Vocabulary
Filter feeder
Porifera
Core Concept
Cnidarians are a phylum of invertebrate animals that have stinging cells and take food into a central body cavity. The
stinging cells allow them to capture food and defend themselves. Cnidarians exhibit radial symmetry. Many adult
cnidarians can move to escape danger and capture food. They are able to reproduce sexually, utilizing external
fertilization, as well as asexually, mostly through budding. Examples of cnidarians include coral and sea anemones.
Vocabulary
Stinging cells
Core Concept
Vocabulary
Worms are invertebrates that have long, narrow bodies without legs. They exhibit bilateral symmetry. They have tissues,
organs, and organ systems. Worms reproduce both sexually and asexually. Worms are divided into three groupsflatworms (phylum Platyhelminthes) , roundworms (phylum Nematoda) and segmented worms (phylum Annelida).
Core Concept
Mollusks (phylum Mollusca) are invertebrates with soft, unsegmented bodies that are often protected by a hard outer
shell. They exhibit bilateral symmetry. There are three major groups of mollusks-gastropods, bivalves, and cephalopods.
Gastropods, such as snails, have a single external shell or no shell at all. Gastropods move by the use of a muscular foot.
Bivalves, such as oysters, are two-shelled mollusks that utilize filter feeding. Adult bivalves stay in one place or move
slowly through the water. Cephalopods, such as the octopus, are ocean-dwelling mollusks whose foot is adapted to
form tentacles around its mouth. Not all cephalopods have shells. Cephalopods capture prey by using its tentacles and
swim by jet propulsion.
Vocabulary
Bivalve
Cephalopod
Gastropod
LIFE SCIENCE
Core Concept
Vocabulary
Birds (phylum Chordata) are a class of endothermic vertebrate animals whose bodies are covered with feathers and have
a four-chambered heart. They have the ability to fly using their wings. Birds have internal fertilization and lay eggs. They
exhibit bilateral symmetry. Most parent birds will care for their young until they are able to fly.
Core Concept
Vocabulary
Mammals (phylum Chordata) are class of endothermic vertebrate animals that have a four-chambered heart and skin
covered with fur or hair. Most mammals are born alive and are fed with milk produced by the mother. Most mammals
walk or run on four limbs. They have bilateral symmetry. Mammals are classified into three groups based on how their
young develop-monotremes, marsupials, and placental mammals. Mammals usually care for their young for an extended
period of time. All mammals reproduce with internal fertilization.
Core Concept
Arthropods (phylum Arthropoda) are invertebrates that have an external skeleton, a segmented body, and jointed
appendages. The major groups of arthropods are crustaceans, arachnids, centipedes and millipedes, and insects. They
have bilateral symmetry and most reproduce sexually. Arthropods have mouthparts that are specialized for chewing
their food. Most arthropods have the ability to move through the use of legs. Insects have wings that allow for flight.
Crustaceans include crabs and shrimp. Arachnids include spiders and ticks. Insects include mosquitoes, bees, and
grasshoppers
Vocabulary
Arthropod
Core Concept
Fish: Fish are vertebrates that live in water and breathe with gills. Fish are ectotherms, or cold-blooded. Fish have either backbones
of cartilage or bone. Most fish are adapted to live in salt or fresh water. Most fish have fins and scales, which cover and protect the
body. The body systems of the fish, such as the digestive, circulatory, etc. are well developed. The fish are further classified into
three classes. These classes are the jawless fish such as the hagfish and lampreys; the fish whose skeleton is made of cartilage such
as sharks, rays and skates; and the fish whose skeleton is composed mostly of bone such as bass, perch, catfish, and flounder.
Vocabulary
Core Concept
Reptiles: Reptiles are vertebrates which can breathe air and are cold blooded (cannot regulate body temperature).
Their bodies are covered with scales or scutes (similar to scales but typically found on feet of birds and crocodiles and
shells of turtles) and they lay amniotic eggs (embryos develop inside amniotic membranes) on land. Reptile’s
characteristics include internal fertilization, as sperm gets deposited into the reproductive tract of the female directly.
The offspring of reptiles resemble the adults at the time of birth itself. There is no metamorphosis, as in the case of
amphibians. Physical characteristics of reptiles include their keen sense organs, which help them to find food and escape
from predators. Eyes are one of the most important sense organ and in most reptiles; these organs are located at the
front of the head to facilitate binocular vision
Vocabulary
Scutes