The life of every living thing on earth has a cycle. This cycle will continue to act on the same species even though the individuals are different. A living being begins to begin its life when it is born on earth.
Humans begin life on earth when they are born. He will grow up to be old with physical and mental changes gradually according to his age. He will live life until he dies, until his breath stops.
Animals are the same, they have a series of life. From birth to death. It grows according to age and phase of life. The process of animal growth and development is called the animal life cycle.
To understand more about the life cycle of animals, Sinaumed’s can listen to the following explanation.
Definition and Characteristics of Animals
According to Anshori, animals or beasts are a group of organisms that are grouped in the kingdom animalia or metazoa. As for the Big Indonesian Dictionary (KBBI), animals are animate creatures that are able to move (move places) and are able to react to stimuli, but are not intelligent (such as dogs, buffaloes, ants); animal.
Meanwhile, according to Wikipedia, animals, fauna, animals, animals are multicellular eukaryotic organisms that make up the animal kingdom. As for Law Number 41 of 2014, the definition of animals is divided into three, namely animals, pets, livestock, and wild animals. Here’s an explanation of the three.
- Article 1 paragraph (3) states: Animals are animals or animals which all or part of their life cycle are on land, water and/or air, either kept or in their habitat.
- Article 1 paragraph (4) states: Pets are Animals whose lives partially or completely depend on humans for certain purposes.
- Article 1 paragraph (5) states: Livestock are pets whose products are intended as food producers, industrial raw materials, services, and/or their byproducts related to agriculture.
- Article 1 paragraph (6) states: Wild Animals are all animals that live on land, water and/or air that still have wild characteristics, both those that live freely and those that are reared by humans.
The characteristics of animals according to Anshori are as follows.
- Animals or animals are eukaryotic, multicellular, and heterotrophic organisms. In contrast to autotrophic nutrition in plants, animals incorporate ready-made organic matter into their bodies by ingestion or eating other organisms, or eating decomposed organic matter.
- Animal cells do not have a cell wall that supports the body tightly, as they do in plants or fungi. The largest component of animal cells consists of the structural protein collagen.
- Another uniqueness of animals is the existence of two tissues that are responsible for the transmission of impulses and movement, namely nervous tissue and muscle tissue so that they can move actively.
- Most animals reproduce sexually, with the diploid stage dominating their life cycle.
- Respiratory organs in animals vary depending on where they live, some breathe with lungs like cats, gills like fish, skin like worms, trachea like insects.
- Animals need food to grow, develop and survive. There are three types of animal food, namely carnivores (meat eaters), herbivores (plant eaters), omnivores (all eaters).
Classification of Animals
In general, animals belong to the kingdom animalia. Launching from Kompas.com, the kingdom animalia is grouped into two, namely the group of invertebrates (animals without backbones) and the group of vertebrates (animals with backbones). The following provides a more detailed description of the two groups.
1. Group of Invertebrates
Invertebrates are a group of animals that do not have a backbone. This group of animals consists of sponges, coelenterata, platyhelminthes, nemathelminthes, annelids, and molluscs. The following is an explanation of the types of animals in the invertebrate group.
a. Porifera
Porifera are animals that have pores in their body structure. The word porifera comes from the Latin, namely porus which means small hole or pore and ferre which means to have.
Most sponges live in shallow seas to a depth of 3.5 meters. They only consist of one tribe (family) that lives in fresh water, namely spongilidae. The rest live in the ocean.
Its body shape is similar to a flower vase and attached to the bottom of the water. It also consists of two layers of cells with the outer layer composed of flattened cells ( pinacocytes ). Porifera digest food via choanocytes. Digestion is carried out intracellularly.
Food that has been digested will be circulated by amebocyte cells to other cells. Meanwhile, the remaining food substances will be excreted through the osculum along with water circulation.
b. Coelenterata
In general, coelenterata live in the sea, except for a few types of hydrozoa which live in fresh water. Coelenterata itself is also called cavity animals and anteron which means intestine. Coelenterata belong to the diploblastic animal group (animals that have two embryonic layers).
This is because the body is composed of two layers of cells, namely ectodermal cells (epidermis) and gastrodermis (endodermis). Between the two layers is a non-cellular layer, namely the mesoglea which is spread over the nerve cells.
Coelenterata body shape consists of two forms, namely polyp and medusa. Polyp is a coelenterate life form that attaches to its place of life. Meanwhile, the jellyfish-shaped medusa is similar to an umbrella or parachute or like a bell that can swim freely.
c. Platyhelminthes
Platyhelminthes or also called flatworms have a soft, flat body shape and ciliated epidermis. It has no body cavity and generally lives in seawater, fresh water and moist soil. Not infrequently, it lives as a parasite in humans and animals.
Flatworms do not have a circulatory system and a respiratory system. It performs incomplete digestion without anus. Meanwhile, for the excretory system through two excretory channels that extend and empties into the pores.
The canals are located in a row on the dorsal side. It also branches and ends in fire cells.
d. Nemathelminthes
Nemathelminthes is a peseudoseomata triploblastic animal or also known as a thread worm. Characteristics, the body is elliptical covered with cuticle and equipped with a complete digestive system.
Unfortunately, threadworms do not have excretory and respiratory systems. Habitat is in wet land, swamps, rice fields, and sea water.
e. Annelids
The nervous system of annelids consists of a brain ganglion connected by an elongated nerve cord that forms a rope ladder. Annelids are also known as roundworms. Annelids have a perfect digestive system starting from the mouth, digestive tract, and anus.
f. Mollusca
Molluscs are soft animals that live in sea, fresh water or on land. This animal has a shell, a complete digestive system, and has legs. It lives in damp places. Respiration is carried out using gills or the mantle cavity.
2. Vertebrata Group
The vertebrate group is a group of animals that have a backbone. This group consists of a group of fish (fish), amphibians (amphibians), reptiles (reptiles), aves (birds), and mammals (mammals).
The following describes the five groups.
a. Pisces (Fish)
Pisces or fish are included in the group of vertebrate animals. This is caused by fish having a skeleton composed of hard bones and containing calcium phosphate.
Pisces habitat is in the water. The outside of the body is protected by an exoskeleton in the form of scales. It moves with its tail and fins. The respiratory system uses gills and has no ears.
The examples of Pisces are goldfish, betta fish, milkfish, tuna, and so on.
b. Amphibia (Amphibian)
Amphibians live in two realms, namely water and land. They breathe with their lungs and skin. It uses gills when it is still a tadpole. His heart consists of three chambers.
The heart consists of three chambers. Amphibians reproduce by producing eggs and not shelling. An example is the frog.
c. Reptiles (Reptiles)
Reptiles are characterized by hard, scaly and dry skin. They are made of antler substance. The function of reptile scales is to prevent drying out.
Reptiles became the first animals that could adapt in dry areas. When walking, he uses grates or feet. Reptiles breathe with lungs. For example snakes, alligators, crocodiles, turtles, lizards, and so on.
d. Aves (Birds)
Aves can be identified by their body which has feathers and a beak made of keratin. Aves feathers form lovebirds which function to help fly. Its habitat is in the air.
Aves breathe through lungs and additional tools in the form of air sacs. The air sacs themselves function as a reserve for breathing air when flying far away.
How to reproduce by laying eggs. The eggs have large shells and yolks. Examples of animals that fall into the aves category are chickens, pigeons, sparrows, sparrows and so on.
5. Mammals (Mammals)
Mammals produce milk to feed their young. Milk is produced by the mammary glands in the stomach or chest area. In addition to having mammary glands, mammals also have three middle ear bones and hair.
Usually, mammals live on land, but there are several types of mammals that live in water. For example whales and dolphins.
The body structure of mammals adapts to the way of life. Some live by flying, swimming, running, gliding, and so on. Breeding by giving birth to children and fertilization occurs in the mother’s body.
Mammals breathe with lungs and have a diaphragm as a breathing apparatus. As for mammals, they include giraffes, horses, cats, elephants, and so on.
Definition of Animal Life Cycle
Launching from kompas.com, animals have their own life cycle. The life cycle of animals can be interpreted as part of the stages of animal development from hatching or birth to adulthood.
According to Inggit Awanda, every animal has a different life cycle. For example in goats and chickens. Both have changes in shape similar to their parents or do not experience changes in body shape at their growth stage.
The life cycle of animals occurs naturally to prevent extinction. Developing and breeding are part of the animal’s life cycle.
Types of Animal Life Cycles
The life cycle of animals can be grouped into two, namely the life cycle without metamorphosis and with metamorphosis. Metamorphosis itself is an animal’s life cycle in which there are stages of biological development in which changes in appearance and/or structure occur after birth or hatching.
The following describes the types of animal life cycles.
1. Animal Life Cycle Without Metamorphosis
An animal life cycle without metamorphosis is an animal life cycle that occurs without any change in form. For example in chickens and cats.
The hen produces eggs which hatch after being incubated by the mother for about 21 days. When hatched, chicks have very fine down. However, when they grow up, the chicks’ feathers will change to those of their parents. Then, adult hens will produce eggs again after fertilization occurs.
This is also experienced by cats. The female cat gives birth to kittens which will grow into adult cats. It grows similar to its mother. The baby cats when they grow up will breed again.
2. Animal Life Cycle with Metamorphosis
Animals that have a life cycle with metamorphosis will have a different physical form when they are born and when they are adults. Physical changes occur due to cell growth and cell differentiation. Or a process occurs that allows less specialized cells to become more specialized.
Metamorphosis is grouped into two categories, namely complete metamorphosis and imperfect metamorphosis. Sinaumed’s can listen to the details in the presentation below.
a. Perfect Metamorphosis
Complete metamorphosis occurs when the process of changing the body shape of an animal from small to adult. Usually animals that have a perfect life cycle go through four stages in their life cycle, namely egg-larvae-pupa (chrysalis)-adult (imago).
Quoting from the book Natural Sciences: The Life Cycle of Animals in the Surrounding Environment by Inggit Awanda, et al mentions examples of perfect metamorphosis in butterflies and mosquitoes.
The butterfly life cycle begins with the eggs laid by the female. Eggs are laid on the leaves. Then it will hatch into a larva (a young animal that will change shape as an adult). Butterfly larvae are called caterpillars.
Caterpillar food is leaves. The longer it takes, the less intense the caterpillar will eat the leaves and the movement will become slower. Then, it stays still or doesn’t move and wraps itself in thread. The threads are formed from saliva. After the whole body is wrapped in thread, it will turn into a cocoon or pupa.
When it becomes a cocoon or pupa, the caterpillar stops eating. Slowly, the cocoon becomes perfect and the butterfly will come out of the cocoon. Then. Adult butterflies will repeat the cycle from laying eggs to becoming adults.
Meanwhile, mosquitoes breed by laying eggs in standing water. Once spawn will produce hundreds of eggs. The eggs will hatch into larvae or grubs. It moves in water.
After a few days, the larvae will turn into cocoons. Then, it will turn into a mosquito. Adult mosquitoes will lay eggs again and repeat the same cycle in their life cycle.
b. Imperfect Metamorphosis
Incomplete metamorphosis is characterized by immaturity or the body parts of the animal have not yet been formed at birth. However, the animal’s physique is the same as its parent. Usually incomplete metamorphosis occurs in insects, such as cockroaches.
Adult cockroaches will lay eggs. When it hatches it becomes a young cockroach or nymph. The shape is similar to an adult cockroach. However, they are smaller and don’t have wings yet. nymphs develop and change their skin continuously before reaching adulthood.
This change of skin is called ecdysis. After adulthood, cockroach wings will grow maturely. It will also lay eggs again and repeat its life cycle again.