CHAPTER 14 ANIMALS AND BEHAVIOR
SECTION 1WHAT IS AN ANIMAL?
You probably can think of many animals, most of the ones you are thinking about probably have four legs. We also have to consider other animals in our study in order to understand what kinds of animals are living in our world. We will study fish, sharks, starfish, jellyfish, corals, reptiles, amphibians, birds, mammals, and insect to mention some of the animals you may not have thought of. There are over a million species of animals. We may not have discovered all of them. We may rediscover some that we thought were extinct as time passes by.
You are probably also more familiar with animals classified as vertebrates. A vertebrate is an animal with a vertebral column (backbone). There are also invertebrates (without a backbone) like squid, octopus, jellyfish, shrimp, and many more.
So again, what is an animal? Well, an animal is multicellular. Animals are eukaryotic (they have nuclei in their cells and the organelles are enclosed by a membrane). The animal cells themselves are enclosed by a membrane and they do not have a cell wall. Most animals also reproduce sexually (egg and sperm uniting for fertilization). A few may reproduce asexually by budding (like hydra) or by fragmentation (sponges and starfish). Fragmentation is when a piece of an animal is broken off, it will regenerate the other portion of the animal and you end up with two genetically identical organisms. If a starfish loses an arm, it will re-grow a new arm and the arm that was lost will regenerate the rest of the starfish body to become a complete starfish.
Animals also have specialized parts. RECALL: Organization and function, cells > tissues > organs > organ systems > organisms.
Animals are also capable of movement from one place to another. Some move slower, but they are capable of moving. Animals are also consumers; they must feed on other animals in order to survive. They cannot make their own food as plants do.
SECTION 2 ANIMAL BEHAVIOR
Animals move, but they move for a reason most of the time. They may be searching for food, or they may be moving to avoid being food for another animal. They may be looking for a mate, suitable nest sites, new territory, or many other reasons. Animals must do many things for their survival.
Animals are predators and prey organisms. Sometimes they are hunting for food, other times they are being hunted for food. Some animals have special adaptations to capture and avoid being captured. Bees often are yellow and black, which are warning colors to other organisms to avoid them. Some animals have enough “intelligence” to make tools and use them to capture prey. Example: Some chimpanzees have learned to poke sticks into ant hills and the ants will attack the stick. The chimpanzee will remove the stick with the ants and eat the ants. The stick serves as the chimpanzee’s tool.
RECALL: Predator – an animal that captures and eats another animal. Prey – an animal that is captured and eaten by another animal.
Some animals have camouflage that enables them to blend into their environment and “hide” from the predators. Examples: new born deer (fawns) have spots that appear as sunlight spots hitting the ground and the deer may go undetected by a predator only a few yards away. Some caterpillars look like twigs. The insects known as walking sticks look like small sticks. Some insects look like the leaves they feed around in order to avoid detection by predators.
Some animals have other defense mechanisms to avoid being prey. Bright colors often signal the organism is poison. The poison dart frogs have toxins that can easily kill other animals. Most poison frogs are brightly colored. Some animals may be able to spray a chemical onto an attacker. Skunks have the ability to spray an irritant and fowl smelling fluid onto potential predators. The Turkey Vulture is capable of projectile vomiting onto another organism if it feels threatened.
Instincts
Some animals have innate behaviors (do things based on their genetic make-up). Innate behaviors are directly influenced by their genes from their parents. Innate behaviors do not have to be learned.
Learned Behavior
Some animals must learn certain skills. Humans must learn to walk, birds must learn to fly, and lions are taught how to hunt by the members of the pride they belong to. Many animals learn by watching their parents or members of the same species.
Seasonal Behavior: Migrations
Many animals have the capability of moving great distances when conditions turn unfavorable. We call this long distance journey a migration. In North America, the waterfowl (ducks, geese, cranes, etc.) migrate from the arctic tundra to the southern United States and northern Mexico during the winter. These same waterfowl will return to the arctic tundra to nest, raise their young, and spend the summer months.
In Africa, the Serengeti plains animals (giraffe, wildebeest, zebra, gazelle, etc.) live in the southern part of the plains for the rainy season because the grass is lush and green and available for food. During the drought season, the animals must migrate to new habitat in the north. This is many of hundreds of miles they must travel (migrate). The predators also must make the migration to follow their food sources.
The Monarch butterflies in the United States migrate to a specific area in Mexico for the winter. There can be over 4 million Monarch butterflies per acre at this time of year in Mexico.
Hibernation
Some organisms hibernate or go into hibernation during cold periods of the year. The bodily function of these organisms slows down dramatically. Many of the organism’s heart rate drops to almost zero and some may have their temperature drop to just above freezing. Bears undergo hibernation for weeks at a time during the winter. This is the time of year they also give birth and the mother bear will lose many pounds of fat providing food for her own body and producing milk for her cubs.
Estivation
On the other extreme of hibernation, we have some animals that undergo Estivation during extreme hot periods of the year. These organisms are often desert dwellers. Examples include mice and desert ground squirrels. During Estivation, the organisms systems almost completely shut down (heart rate drops and they produce little or no urine, which conserves water).
Biological Clocks or Rhythms
Have you ever noticed squirrels or chipmunks “putting food up” for the winter? Have you ever thought to yourself, “Self, how do the animals know when it is time to put food up for the winter or migrate to a better location?” Well, the answer is biological clocks and circadian rhythms.
An organism’s biological clock is the internal control of natural cycles. Much research has been done on these “clocks” and scientists think the length of daylight and night may have a major control over an animal knowing when to migrate, or put up food for the winter.
Another biological clock is known as a circadian rhythm. Circadian rhythms control daily cycles. Have you ever been in the routine to get up early and then have a day you could sleep late and wake up early any way? That is due to your circadian rhythm. If you notice, you often get sleepy at about the same time each day.
Some animals may have seasonal cycles that tell them when to hibernate, estivate, look for a mate, breed, or many other behaviors that different animals seem to carry out on a seasonal basis.
How Do Animals Know Where to Migrate to? What Path to Take?
There has also been many of hours spent on researching how animals know what path to follow when they make their migratory journeys. Scientists believe several ways are used by animals to know the path. Animals must navigate as humans did before the technology of Global Positioning Systems and other man made devices were available. Many scientists think some organisms travel based on the location of the stars and sun in the sky.
Some scientists believe the organisms become familiar with landmarks (lakes, mountains, or other fixed objects) to navigate by. Many bees, and pigeons seem to use this method. Some birds appear to recall large landmarks like mountain ranges and rivers.
There is also some evidence that some animals especially certain bird species use the magnetic properties of the Earth to navigate by. An analogy would be a person using a compass to travel through a forest. It appears that some birds may have a built in compass because scientists have discovered very small magnetic crystals in the heads of some birds.
SECTION 3 BEHAVIORS WHILE LIVING TOGETHER
If you have noticed, most organisms do not live alone and they associate with members of the same species as well as members of different species. Social behavior is the interaction between animals of the same species.
Many animals are capable of communicating with each other. Some may give warning calls if a predator is approaching, some may make certain noises to attract mates or let others know there is food present. Some animals may carry out behaviors to scare others away.
Some animals are territorial and will defend their territory from members of the same species. Example: Wolf packs howl to warn other packs that the territory is already occupied. It is sometimes easy to understand noise communication by watching what other animals do.
Other Methods of Communication
Some animals may give off a specific smell. These chemicals are often called pheromones. Pheromones are used to attract mates, alert others to danger, or mark their territory.
Certain birds will sing specific notes to attract a mate; others may have a ritual “dance”, while other animals may produce other noises to communicate with their species. Dolphins produce a clicking noise; deer produce a grunting noise,
Actions May Say It All
Some animals have specific body language they present in order to communicate. A skunk raising it’s tail is a form of communication. A dog showing it’s teeth and growling is communication, a lion roaring, a dog wagging it’s tail with a ball in it’s mouth may be wanting to play. A bull stomping and pawing the ground may be warning you to leave his pasture. All sorts of animals have “body language” to communicate with.
When a honey bee locates a source of nectar, the bee will return to the hive and does a “dance” that tells the other bees the location of the nectar so they too can go gather the nectar.
LONERS or GROUPIES
Some animals may live alone like tigers, while others like lions will live in groups. A group of lions is called a pride. The pride will hunt together and take care of the kittens or young lions together.
Benefits of Living in a Group
Many times there is safety in numbers. A large school of fish may appear like one large organism so the fish are not attacked. A group of animals can help each other find different food sources, help defend the group from predators, and care for the young. Musk oxen live in herds and if they feel like a predator is threatening, they will surround (form a circle around) the young and face to the outside of the circle with their horns showing. This creates a protective barrier to the young musk oxen.
Some animals like wolves and lions hunt as a group and if they begin chasing a prey, they will take turns until the prey is too tired to run any more and then they set in for the kill.
Disadvantages of Living in a Group
Sometimes a disease may break out and spread through the animals living together. If there is a limited amount of food, it may not be good to have a large group depending on a small amount of food or resource, so fighting may occur and result in animals hurting each other. Animals living in groups also have to compete for space and mates. A group of animals may also attract predators to an area. When it is birthing season for many herbivores that live in large groups, predators are often attracted because they may get an easy meal (newborn calf that can not run, or some other animals trying to care for the young).
SECTION 1 STUDY GUIDE 14
A ______is an animal with a vertebral column (backbone).
Animals are ______(they have nuclei in their cells and the organelles are enclosed by a membrane).
Most animals also reproduce ______(egg and sperm uniting for fertilization).
A few may reproduce asexually by ______(like hydra) or by ______(sponges and starfish).
______is when a piece of an animal is broken off, it will regenerate the other portion of the animal and you end up with two genetically identical organisms. If a starfish loses an arm, it will re-grow a new arm and the arm that was lost will regenerate the rest of the starfish body to become a complete starfish.
SECTION 2 STUDY GUIDE 14
Animals are ______and _____ organisms.
______– an animal that captures and eats another animal.
______– an animal that is captured and eaten by another animal.
Some animals have ______that enables them to blend into their environment and “hide” from the predators.
______colors often signal the organism is poison.
Some animals have ______behaviors (do things based on their genetic make-up) These behaviors are also called instincts.
Many animals have the capability of moving great distances when conditions turn unfavorable. We call this long distance journey a ______.
Some organisms ______or go into hibernation during cold periods of the year.
On the other extreme of hibernation, we have some animals that undergo ______during extreme hot periods of the year.
An organism’s______clock is the internal control of natural cycles.
______rhythms control daily cycles.
Some scientists believe the organisms become familiar with ______, which are recognizable locations.
There is also some evidence that some animals especially certain bird species use the ______properties of the Earth to navigate.
SECTION 3 STUDY GUIDE 14
______is the interaction between animals of the same species.
Many animals are capable of ______with each other.
Some animals are ______and will defend their territory from members of the same species.
Some animals may give off a specific smell. These chemicals are often called ______.
Some animals have specific ______language they present in order to communicate.
Many times there is safety in ______.
Sometimes a ______may break out and spread through the animals living together in large populations.
What are some disadvantages of living in a large group?