Life Update

So I have made my final decision about this part of my life...I am moving to Curacao. 

I will be leaving for the states June 25th. I'll be bringing my dog with me because my parents are going to watch her for me while I'm there. I will be there for 8 months, and then move back to the states for my internado. I will hopefully be able to come back to the DR to visit. 

I have been so honored to be your teacher this year and will miss you all so much. If you want to follow my future adventures, I have another blog with occasional updates about my life and where I am at. Here is the link to my other blog Kaitlyn's Adventures. Otherwise, feel free to email me if you miss me or have questions: kaitlyn.cunningham@icloud.com or nyltiak@gmail.com.

Thank you for everything this year. I will never forget this experience. 

Miss Cunningham

Class Mammalia

Characteristics

Hair of Mammals

• All mammals have hair.
• Some have more than others.
• Hair: a collection of nonliving cells filled with filaments of the protein keratin
• Two types of hair:
• Underhair: soft, insulating layer next to skin
• Guard hair: coarse, longer, found over the under hair
• Various functions:
• Beavers: waterproof, never gets soaked to the skin
• Camouflage
• Whiskers: sensory nerves, permit them to detect objects in their path
• Porcupine: barbed quills that protect them from predators

Leopards use their fur as camouflage

Porcupines use theirs for protection

Limbs of Mammals

• Usually have two pairs of limbs used for locomotion
• Look different in different animals
• Bats: elongated fingers connected by thin membranes for wings
• Moles: shovel like limbs (dig around 4 m/h)
• Whales: paddles for swimming

Whales use their front limbs as paddles

Lions use their front paws to help catch their prey

Moles use their paws as shovels

Digestion of Mammals

• If something is edible, there is probably some mammal that eats it.
• Mammals eat grass, leaves, fruits, seeds, bark, tree sap, microscopic organisms, blood, honey, invertebrates such as insects and snails, and vertebrates, including other mammals.
• A variety of teeth:
• Incisors: flat, thin teeth in the front of the mouth, used in gnawing or biting.
• Canines: rounded, pointed teeth towards the front of the mouth, used for tearing
• Molars: usually thick, squat teeth in the back of the mouth, used for grinding and chewing
• Carnivores usually have enlarged canine teeth.
• Gnawing animals have large incisors.
• Herbivores cut the foliage with the incisors and chew with molars.
• Omnivorous such as monkeys and bears have well-formed teeth of each type.
• Some animals have special structures or processes to process their food.
• Those that eat plants:
• Chew the cud
• Special enzymes
• Compartments in the stomach

Respiration and Circulation

• Oblong spongy lungs in the upper chest cavity.
• Separated from abdominal organs by diaphragm
• Air drawn into lungs by contraction of diaphragm
• Air passes down throat, through larynx (voice box)
• 4 chambered heart
• Complete separation of oxygenated and deoxygenated blood
• Circulatory system similar to man’s
• Expend energy to maintain constant body heat
• Mammals that live in hot climates have mechanisms to keep cool
• Those in cold climates have mechanisms to keep them warm.

Polar bears have proportionately small heads

Elephants take mud baths

Response

• The cerebrum—the center of intellect and instinct—dominates the mammalian brain, making mammals the most intelligent animals.
• Also used for memory 
• Many express emotions such as fear, anger, contentment, excitement, and happiness.
• Sensory organs are similar to those of man, but sensitivity is different.
• Bats hear better
• Dogs smell better

Reproduction

• Most mammals have young that develop internally, nurtured by a placenta.
• Interface between mother and offspring through which gases, nutrients, and wastes are exchanged.
• These exclude marsupials (pouched mammals) and monotremes (egg layers)

Placental Mammals 

• Female mammals paired ovaries produce and release ova. Guided through a tubular oviduct toward the uterus.
• When a female’s ova are ready to be fertilized the animal enters a period called estrus or “heat”
• Various odors are released by the female at this time to attract the male.
• The male’s testes produce sperm. Internal fertilization takes place. The sperm is carried in a liquid to the egg where it fertilizes it in the oviduct. Before it has reached the uterus, the zygote has divided several times.
• First few cells of the animal are implanted in the uterine wall. 
• Placenta is formed of some uterine cells and embryonic cells.
• Rich blood supply
• Exchange of nutrients, gases, wastes
• The two blood supplies don’t actually mix
• Blood vessels form an umbilical cord
• The length of pregnancy is called gestation.
• Gestation varies depending on species. Generally the longer the gestation the more developed the baby.
• Rats: 21 days
• Horses: 335 days
• After baby is born, mother supplies milk from mammary glands
• Many mammals train their young to hunt, select fruit, build shelters, etc. before they leave the family.

Marsupials: The Pouched Mammals

• Kangaroos, koalas, and other marsupials produce young without a placenta. Fertilized egg begins growing and dividing within the uterus, but does not implant itself.
• Nourished by a small yolk sac. When the yolk sac is depleted, the baby crawls out of uterus.
• It must then crawl from there to the pouch. It can then start to feed on milk. Completes its development in the pouch. 

Monotremes: Egg-Laying Mammals

• Exception to many mammalian characteristics. 
• Single hole for digestive, excretory, and reproductive systems.
• Lay eggs and incubate them like birds.
• Young drink milk, but they don’t have nipples. Milk empties onto the skin and the young lap it off the fur.

What to study for quiz on Wednesday

Focus on the following life processes of birds:

• Respiration
• Digestion
• Ability to fly

Also feathers and limbs

Bird Family Life

• For birds, the process of reproduction and raising young is quite complicated, usually involving courtship and nest construction.
• Courtship is the male bird attempting to attract a mate.
• Males are more colorful than females.

• Birds are oviparous, producing amniotic eggs.
• Male transfers his sperm into the cloaca of the female (internal fertilization).
• Females have a single ovary for ova production.
• Fertilization occurs within the oviduct.

• Embryo appears as a small nucleus in the yolk.
• Yolk is coated with protein-containing substance called albumen (the white part of the egg). 
• Encased in a shell.
• The shell may range in color from white to almost black, and it may have markings like spots, splotches, or streaks. While a bee hummingbird egg is the size of a pea, an ostrich egg may weigh 1.5 kg (3.3 lb) and could hold 4700 of the small hummingbird eggs.

• Eggs and young birds require parental care.
• The egg require incubation. Usually one or both parents do it.
• There are two types of chicks after they hatch:
• Altrical chicks
• Precocial chicks
• Altrical chicks
• Hatch in less than two weeks and emerge naked, blind and helpless.
• All they can do is open their mouths and eat.
• Parents produce less than 6 eggs at a time.

• Precocial chicks
• Longer incubation period, sometimes as long as a month.
• When hatched, they are well developed, alert and able to move.
• Covered with soft down.
• Stay close to parents for protection.

• Most birds have a reproduction cycle of one year, each year with a different mate. 
• Some birds mate for life.
• Eagles and penguins.

Migration

• The ideal place for raising offspring may not provide suitable year-round conditions. Some birds overcome this dilemma by migrating.
• Almost 1/2 of all bird species in the Norther Hemisphere travel south in the winter and north in the summer. 
• Seasonal, predictable, and repeatable on an annual basis.
• Why migrate?
• They can live all year in warm climates where there is lots of food.
• Best environment for raising young.
• The time, route, destination, and other aspects of bird migration are inborn.
• Mechanism for navigation not completely understood.
• Might use landmarks, but some fly over open water.
• Birds have an instinctive sense of direction.
• Some detect magnetic poles
• Some use stars and sun
• The arctic tern covers the greatest distance.
• 17,700 km from the Arctic Circle to Antarctica.

Bird Systems

Birds must accomplish the same internal processes as all other vertebrates— digesting and absorbing food, bringing oxygen and nutrients to the cells, eliminating carbon dioxide and other wastes, and responding to their environment. The challenge is accommodating these diverse tasks in a lightweight flying package. Each of the familiar life processes discussed in this section is uniquely modified by the Creator to serve a bird’s high-energy lifestyle.

Digestion in Birds

• High body temperature and flying means they have an enormous energy demand.
• So they eat large quantities of food.
• Some adult birds can eat a quarter of their weight in a day
• Once ingested, the food is quickly digested.
• This is essential because birds cannot afford to carry heavy quantities of food in their stomachs.
• Uses its unique beak for gathering food.
• Appearance and use vary with the bird’s diet. 





• Food is usually swallowed whole, passes through the esophagus and enters the crop.
• Crop is a holding area for the food.
• From the crop, it passes into the first part of the stomach (proventriculus)  where digestion juices are produced.
• The gizzard is the second part. Here the food is ground down by sand and stones that the bird swallows. 
• The food then passes into the intestine, where final digestion and absorption occurs.
• Undigested wastes are passed into the cloaca and then out of the body. 
• The cloaca is a common opening for the intestines, kidney ducts, and reproductive organs.

Respiration

• Their lungs are unable to provide enough oxygen.
• A series of air sacs aids the lungs.
• 25% of the air is draw in the lungs & 75% to the air sacs.
• As the bird exhales, the air in the lungs passes out, and the fresh air from the air sacs passes through the lungs.
• Fresh air passes through the lungs during inhaling and exhaling. 
• Respiration also helps them remain cool. 
• They sweat a little, but not enough. 
• They pant like dogs.
• Also used for vocalization.
• They have a syrinx (song box). 
• They perfect the call by imitating others from their species. 

Circulation and Excretion

• 4 chambered heart
• What does this mean? 
• Complete separation of oxygenated and deoxygenated blood.
• Right side of heart receives the blood and pumps it to the lungs.
• Lungs oxygenates the blood which then goes to the left side of the heart. 
• From there it is pumped to the body. 
• To maintain their high metabolism, the heart beats rapidly. Average of 135-570 bpm. Some species can reach 1000 bmp.
• Birds generally don’t die of old age, but “burn themselves out.”
• They have high blood pressure and can die of heart failure in times of stress.
• Metabolic wastes are filtered from the blood by a pair of kidneys. 
• Waste empties directly into the cloaca. 
• No bladder. Makes them lighter for flight.

Response

God’s design becomes more obvious from a study of the various animals. Reptiles, amphibians, and fish rely heavily on the senses of smell and taste. In contrast, their vision and hearing are weak. Many of these animals live in a watery environment that muffles sound and reduces light, making hearing and vision of little value. Even those reptiles and amphibians living on land have little use for strong eyes; they live in or close to the ground, limiting their field of vision. God provided the specific senses these animals need for their activities and environment.

• Birds have large, generally immovable eyes. Birds must move their neck to look around. 
• Some birds have better eye sight than us. 
• A hawk can spot a rabbit  from 1.5 km away. 
• Owls can spot prey in 1/10 to 1/100 of the brightness needed for man to see.
• Birds have ear canals covered by feathers.
• They have sensitive hearing in the upper sound range.
• The brain of the bird is larger than all other vertebrates except mammals.
• Olfactory lobes are small, smell is not important (except for birds that feed on dead animals.
• The cerebrum, responsible for instinct, is also large.
• Optic lobes are large.
• Cerebellum, coordinates the muscular activities, is large.

Class Aves: The Birds - Characteristics

Flight

• More than 9000 species can fly
• Those who are too heavy to fly, often “fly” underwater
• All birds have feathers, protein based structures that provide covering, insulation, and shape
• Front limbs covered with feathers - wings
• More than just wings:
• Birds bones are hollow, to reduce their weight

• Requires enormous amount of energy and lots of oxygen.
• Just two lungs, but they are connected to many sacs to multiply the volume.
• High metabolism allows them to access energy quickly
• Keeps their internal temperature at 41 degrees C (106 degrees F)
• No teeth, just a beak that makes them lighter
• All oviparous, they don’t have to carry them in their body

Feathers of Birds

• Make the birds aerodynamic
• Retains heat
• Cushion during collisions
• Camouflage & identifying a mate
• Common types of feathers:
• Down feathers: provide insulation as well as a cushion
• Contour feathers: cover the body and give it shape and color
• Flight feathers: extend from the wings and tail

Because feathers are dead, they must molt.

It is a very orderly process to make sure that they can still fly.

Feathers molt one pair at a time. No more feathers are lost until the molted pair are replaced.

Appendages of Birds

• Wings for flying (unless you are a penguin or ostrich)
• Not used to manipulate things
• Long flexible necks are substitutes for arms and hands
• Legs are thin and covered with scales with three or four clawed toes.
• Depends on the type of bird and their function

Skeleton of Birds 

• Unusual features of the birds skeleton:
• Upper jaw and lower jaw are elongated and form a beak.
• Many neck vertebrae grant free movement of the head.
• The vertebrae of the tail are free moving and help to guide it in flight
• The trunk vertebrae, the flat ribs, and the sternum are fused to make the trunk a rigid framework
• The large sternum has a central ridge called a keel. It provides attachment for flight muscles
• The clavicles are enlarged and fused, forming the “wishbone.” This also provides attachment for flight muscles.

Study Guide for Quiz Monday April 7th

• Characteristics of Phylum Chordata:
• Dorsal notochord
• Dorsal tubular nerve chord
• Pharyngeal pouches

Vertebrate Classification

• Ectothermic
• Endothermic

Vertebrate Support

• Axial skeleton
• Appendicular skeleton
• Pectoral and pelvic girdle

Vertebrate Circulation

• Blood vessels
• Hemoglobin

Nutrition

• Herbivores
• Carnivores
• Omnivores 

Vertebrate Reproduction

• Types of fertilization
• Methods of development
• Oviparous
• Viviparous
• Ovoviviparous

Behavior

• Inborn
• Conditioned
• Intelligent

Nervous System

• Five lobes of brain

The Fish: Part 1

• Genesis 1:26 “have dominion over the fish of the sea”
• Main food source
• Good form of fertilizer
• Used to make glue
• Entertainment (aquariums)
• Three classes of fish
• Class Agnatha
• Class Chondrichthyes
• Class Osteichthyes 

Class Osteichthyes

• Characteristics
• Most fish we think of are in this class.
• Some unusual members such as sea horses
• Typical flat, spindle-shaped body
• Others flat on the bottom, round like a pencil, can look like boxes, pyramids, or balls
• Usually less than 1 meter in length 
• Support and Movement
• Bony skeletons (Bone is cartilage hardened by mineral deposits)
• Vertebral column and skull of bone
• Ribs, pectoral, and pelvic girdles are often cartilage (but can be bone)
• Move through the water by the whipping motion of its body. 
• The power comes from wavy, muscular bands found in the fish’s trunk and tail.
• Fish are denser than water, so why do they float
• Swim bladder: thin-walled sac in the body cavity that enables fish to control its depth and maintain it without swimming.
• Gases diffuse in and out of the SB through the bloodstream. 
• Fins
• Used for guidance or slow swimming movement. 
• Unusual ones: 
• Sea robin uses its pectoral fins to “walk”
• Walking catfish can hold water in its gills, and walk across land for long distances
• Flying fish use them for gliding through the air
• Can go 55 km/h and up to 46 m

• Body Coverings
• Overlapping scales. The number does not change, just the size in proportion to their bodies.
• Some fish, like some catfish are scaleless. 
• Some catfish have bony plates. 
• Sturgeon have rows of large enamel-like plates.
• Special glands beneath the scales secrete mucus.
• Nearly waterproof coating
• Lubricates the fish for smoother movement through the water (reduces friction by 66%)
• Chromatophores: branched cells responsible for producing some of the pigment in fish scales.
• Some fish can change their color or pattern
• Change color in response to temp., diet, states of excitement, and physical condition.
• Digestion
• Feed on plankton, worms, insects, other fish, and even some mammals.
• Ingested through mouth (which often contains teeth to bite or hold prey)
• Fish mouths vary depending on their prey
• The direction of the mouth points to where it eats
• Food passes through a flexible throat, or pharynx and a short esophagus into a saclike stomach for storage.
• Digestion occurs in a short intestine.
• Short tubes called pyloric ceca (at junction of stomach and intestines) secrete digestive enzymes.
• Liver, near stomach, secretes bile to aid in digestion of fats.
• Most fish have a gallbladder (stores and exerts bile) and a pancreas (secretes other digestive enzymes).
• Indigestible food eliminated via the anus.

• Respiration
• Almost all fish have an operculum: a plate behind the eye on each side of the head.
• Under this is a series of gills 
• Gills consist of two rows of thin gill filaments on a band of cartilage called the gill arch.
• Each gill filament consists of a sac of thin epithelium and richly supplied with blood vessels.
• Gill rakers are a number of cartilage projections on the inner part of the gill arch. They keep food and debris from entering and clogging the gills.
• Circulation
• Circulation of blood enables oxygen and nutrients to reach every cell of the fish.
• 2 chambered heart
• Atrium receives the blood
• Ventricle pumps the blood to the arteries
• Single loop system in which the heart pumps blood only to the gills.

• Nervous System
• Major organs: brain & spinal cord.
• 10 Pairs of cranial nerves branch from the brain
• Many spinal nerves
• Large optic lobe: They could see well if it weren’t for the fact that they live in water.
• Great sense of smell. People taste water, fish smell it.
• Tongue for taste and touch
• No external ears, but can detect sound vibratos 
• Sensor hairs: changes in current (detect pressure and movement changes)
• Reproduction
• Some are ovoviviparous and even viviparous.
• But most are oviparous.
• Eggs are laid and then fertilized externally.
• Females in some species produce hundreds of thousands of eggs.
• When environmental conditions are right, the female spawns (lays eggs)
• The male then covers the eggs with milt (a milky fluid containing sperm)
• The embryo usually forms atop of food material called yolk.
• As the embryo grows, the yolk shrinks.
• Eventually a tiny larval fish escapes the egg and fends for itself.
• This process can take hours to 4 months.

Subphylum Chordata: The Vertebrates

Characteristics

• Dorsal notochord: rod of tough, flexible tissue running the length of the animals body.
• Primary support
• In most chordates, before birth/hatching, it is replaced by vertebrae
• Vertebrae together are called the vertebral column or backbone
• Dorsal tubular nerve chord: 
• Passes dorsal to the notochord/or is incased in the vertebrae
• Connected with the brain at the anterior end of the cord
• Develops into spinal chord
• Pharyngeal pouches: 
• Folds of skin that develop either into gills or various structures of the lower face, neck and upper chest

Classification

• Three subphyla:
• Cephalochordata
• Retain their notochords through their entire lives
• Ex. amphioxus (lancelet): a small eel-like creature that sticks it’s head out of the sand and feeds on filtered plankton
• Urochordata
• Have notochords at the larval stage
• Ex. sea squirts: they pump water through their bodies, they keep their pharyngeal slits through adulthood
• Vetebrata
• Most familiar (95% of all chordates)
• Develop vertebral columns before birth
• We will look at this subphylum in this chapter and the next

Subphylum Vertebrata

• Vertebrate variety:
• Includes fish, amphibians, reptiles, birds, and mammals
• They live virtually every where
• From the ocean floor to the fringes of the atmosphere
• Classification:
• Ectothermic (cold-blooded): cannot generate their own body heat
• Must maintain their body temperature from external sources
• Inactive in cold temp.
• Endothermic (warm-blooded): generate their own body heat through physiological changes
• Relatively active
• Seven classes
• Ectothermic
• Agnatha
• Chondrichthyes
• Osteichthyes
• Amphibia
• Reptilia
• Endothermic
• Aves
• Mamalia
• Support
• Supported by an internal skeleton composed of bone and cartilage
• Support, protect, and surround delicate organs
• Axial skeleton: vertebral column, skull and ribs
• Appendicular skeleton: attachment of limbs
• Pectoral and pelvic girdle
• Circulation and excretion
• Closed circulatory system
• Consists of a heart and blood vessels
• Heart can have 2,3 or 4 chambers, depending on the species.
• Ventral to the vertebral column
• Blood vessels: 
• Arteries: carry blood away from the heart to body tissues
• Capillaries: thinnest branches of the arteries. 
• Pass through the body tissues. 
• Supply them with nutrients and oxygen and remove waste.
• Veins: begin with capillaries and cary blood from tissue back to the heart
• Hemoglobin: a red oxygen-carrying pigment. 
• Blood passes through a pair of kidneys to filter out waste.
• Nutrition
• There are three different types of eating habits in subphylum vertebrate:
• Herbivorous: animals that eat plans.
• Grazing animals such as horses or cows.
• Cellulose is hard to break down so the animal uses grinding teeth
• Carnivorous: animals that feed on other animals
• Sharks, lions, and eagles
• Sharp teeth, beaks, or claws
• Omnivorous: animals that eat both plans and animals.
• Varied types of teeth
• All vertebrates have an alimentary canal that is composed of:
• Esophagus
• Stomach
• Intestines
• Some have a liver, gallbladder, and pancreas
• Reproduction
• Sexes are separate
• Males have a pair of testes and females have a pair of ovaries
• Two types of fertilization:
• External fertilization
• Internal fertilization
• There are three basic methods for development:
• Oviparous: produce offspring from an egg that hatches outside the body
• Viviparous: live offspring that have been nurtured to birth inside the uterus (or similar)
• Ovoviviparous: egg remains in the mother’s body and hatches there, then emerges.
• Behavior
• Inborn
• Behavior from birth, does not need to develop
• Reflex behavior: automatic, involuntary response to stimulus
• Blinking, sucking, recoiling from pain
• Instinct behavior: elaborate behaviors, apparently the result of a stimulus or series of stimulus
• Salmon swimming upstream to spawn, mating rituals, flight or fight
• Conditioned
• A response learned by experience
• Training a dog, elephant, or seal
• Encouraged through reward/“punishment”
• Skunk spraying a dog
• Can be learned by watching other members of the species
• Intelligent
• Ability to use tools to manipulate the environment, reason out a solution to a problem, or communicate with symbols.
• Chimpanzees use rocks to open nuts and sticks to “fish” for insects
• Apes have been taught to learn sign language
• Woodpecker finch uses a cactus spike to dig out bugs
• Nervous system
• Contains:
• Brain
• Spinal cord, 
• Cranial nerves (branch from the brain)
• Spinal nerves (branch from the spinal cord)
• Sensory organs (such as eyes, ears, and taste buds)
• Five lobes of the brain
• Olfactory lobes: receive impulses from the smell receptors
• Cerebrum: controls voluntary muscle activity
• Optic lobes: receive impulses from the eyes
• Cerebellum: coordinates muscle activity and some involuntary activities
• Medulla oblongata: transports impulses to and from the spinal cord, includes some reflexes.

Subphlyum Hexoda: Class Insecta

Introduction

• Nearly 1,000,000 species (80% of all animals)
• Some reasons they are so successful:
• They can fly
• Tremendous reproductive capabilities
• Generally don’t compete for food
• They are a major influence on nature and man

Characteristics

• What makes them different from other arthropods?
• Three pairs of walking legs
• Wings, usually
• Bodies divided into three segments: Head, thorax, abdomen
• One pair of sensory antenna
• Movement
• Three pairs of jointed legs along the thorax.
• Used for movement, but types vary depending on what they are needed for:
• Flies have tiny claws and sticky pads (they can climb on smooth surfaces)
• Bees have fuzzy legs (used for collecting pollen)
• Most have 2 pairs of chitinous wings (although some have 1 pair and a few wingless species exist)
• Only invertebrates that can fly
• Flying styles and speeds vary
• Butterfly flaps wings 5-6 times per second
• Bees flaps wings up to 200 times per second
• Flies fly about 8km/h and dragonflies 40 km/h
• There are four different types of wings that vary based on need and use
• Membranous wings: thin, transparent, and crisscrossed with supporting veins. Most have this type

Membranous Wings

• Scale-covered wings: the flight wings of butterflies and moths are covered with delicate, beautifully colored scales that rub off easily

Scale-covered wings

• Leatherlike wings: grasshopper’s membranous wings covered by a pair of leather like wings 

Leather-like wings

• Horny wings: the front wings of beetles are thick shields that cover most of the dorsal surface of the insect

Horny wings

• Nutrition
• Ingestion:
• Variety of different types of mouthparts called mandibles
• chewing
• sponging
• siphoning
• piercing
• Three main parts of digestive system:
• Foregut: food enters through the mouth, it is moistened with secretions from the salivary glands, passes through to the gizzard where it is thoroughly ground
• Midgut: gizzard opens into the stomach. Digestive juices digest the food.
• Major site of digestion and absorption.
• Hindgut: solid residue left in the midgut after digestion passes through the hind gut, or intestine, and out through the rectum and anus
• Respiration, circulation, and excretion
• Respiratory system of insects is an elaborate system of tubules called tracheae that branch throughout the animal.
• This system is so complete that oxygen is transported throughout the animal without using the circulatory system.
• These tubules open to the outside through a sereis of spiracles, small pores that run along each side of the animal. 
• The insect “breathes” as abdominal contractions pump air in and out of the tracheae.
• The open circulatory system is only involved in the transport of nourishment and collection of waste. No gas exchange.
• Cellular waste is extracted by Malpighian tubes and excreted into the intestine for elimination.
• Irritability
• Anterior “brain” connected to an anterior ganglion and ventral nerve cord.
• Receives information from a variety of sources:
• Smell from antennae.
• Many insects produce chemicals called pheromones to find a mate.
• Antennae can sense humidity and flight speed.
• Taste receptors on the mouth parts.
• Tactile hairs on the antennae, limbs and body
• Compound eyes or several simple eyes
• Some have organs to hear
• Reprodution
• Sexes are separate.
• Females store sperm in seminal receptacle
• As she lays her eggs they are fertilized
• Eggs are protected either by where they are laid (deep in tree bark for example) or with protective coverings.
• Metamorphosis


• Developmental changes in insects is called metamorphosis. 
• This permits various stages to perform different functions.
• Ex. some insects eat only during their immature forms and become adults only to reproduce.
• Only a few species of insects do not exhibit metamorphosis.
• Incomplete metamorphosis (grasshoppers)
• The nymph that hatches looks like a miniature, oddly proportioned adult. 
• As it grows and molts it becomes more like the adult.
• Same diet and habitat for the nymph and adult.
  
  

• Complete metamorphosis (90% of all insects)
• Involves 4 stages: egg, larva, pupa, and adult
• Egg hatches into larva (a segmented wormlike stage)
• Some common names: maggots, grubs, caterpillars
• After period of eating and molting, the larva enters the pupal stage.
• The pupa makes a cocoon around itself (woven silk case).
• Though it is quiet on the outside, it is a period of significant activity and grown. 
• During pupal stage, the organs are dismantled and completely reshaped. 
• Eventually the cocoon opens revealing a fully developed insect. 
• This process is controlled by hormones. 
  
  
  

Subphylum Chelicerata: Class Arachnida

General Characteristics

All have mouthparts called chelicerae (appear as claws or fangs)

Most are completely harmless (some have painful stings, transmit diseases, or can kill you) 

Like insects they have small, compact bodies and long, delicate limbs, but they are not insects. 

Here are the characteristics that separate them: 

4 pairs of walking legs 

Bodies divided into two major segments (cephalothorax and abdomen)

No antennae or mandibles

Respiration by book lungs 

Usually 4 pairs of simple eyes 

 

Class Arachnida

• Characteristics
• 6 pairs of appendages:
• one pair of chelicerae (with poisonous fangs used to paralyze prey)
• one pair of pedipalps used for sensory reception and in males to transfer sperm
• 4 pairs of walking legs

• Nutrition:
• All spiders spin silk used for containing eggs, restraining prey, or building a web.
• Originates as a liquid protein and is released through organs called spinnerets. 
• Not all spiders catch prey in their webs. Some prowl on the group and ambush their prey.
• Once a spider has they prey, they immobilize them with a bite from the chelicerae and inject digestive juices into the victim. 
• The spider then sucks up the partially digested tissues using its stomach and pharynx.

• Respiration:
• Only arachnids have and use book lungs for respiration. 
• Air enters the spider through a slit in the abdomen and flows between folds of the book lungs where gas is exchanged.
• Reproduction:
• The sexes are separate. Females are often larger.
• Male places his sperm in a tiny web sac and stores it in special cavities of his pedipalps. He then transfers it to the female after a courtship offering of food.
• In some species, the female will eat the male after mating.
• As she lays her eggs, they are fertilized by the stored sperm.

 

Subphylum Crustacea

Crustaceans

• Most crustaceans are free-living and aquatic (although there are some parasites and terrestrial species).
• We are going to look at the crayfish as our example of a crustacean. 

The Crayfish

Crayfish

• Covered with a tough exoskeleton
• Divided into three segments: cephalothorax and the abdomen (composed of 6 different segments)
• Beneath the abdomen are a number of paired, small, flipper like appendages called swimmerets (used for swimming and reproduction).
• There are four pairs of walking legs and a pair of prominent chelipeds (or pinchers) attached to the cephalothorax. 

Life Processes

• Movement:
• Muscles
• Legs
• Swimmerets and walking legs
• Nutrition:
• Scavengers: eating virtually any edible material.
• The mouthparts of the crayfish reduce the food to swallowable size.
• Then moves to esophagus then to the anterior part of the stomach where it is ground to fine particles by muscular action and chitinous teeth of the gastric mill.
• The food is sorted in the posterior part of the stomach.
• Food is then moved to the intestines. Undigested food moves through the anus.
• Respiration:
• The crayfish as two sets of feathery gills found in the two lateral gill chambers along the thorax.
• Appendage movement and feathery mouthparts help to keep oxygenated water flowing through the gills. 
• Blood traveling through the thin-walled gills releases carbon dioxide and absorbs oxygen.
• Many can store water in their gill chambers in order to walk on land. The “hold their water” like people “hold their breath.”
• Circulation:
• Open circulatory system.
• Blood collects in the a cavity surrounding the heart. 
• Blood enters the dorsal heart through tiny openings.
• As the heart contracts, valves close to keep the blood from flowing back into the sinus.
• The blood then leaves the heart, bathing the organs with oxygenated blood, to then be collected in the sternal sinus.
• The blood passes again through the gills and the process starts again.
• Excretion:
• Excretion is performed by green glands, which are located near the base of the antennas.
• The green glands filter out waste.
• Fluid wastes are excrete through a pore anterior to the mouth.
• Wastes from the intestines are eliminated through the anus.
• Response:
• Ventral nervous system receives information about the environment from a number of sensory sources.
• Compound eyes
• Antennae
• Antennules, shorter sensory appendages
• Tiny bristles for touch on several appendages
• Statocyst: the organ of balance found at the base of each anteannule
• Reproduction/Regeneration:
• Arthropods cannot reproduce asexually, but as a mode of defense, they can loose an appendage and it will grow back.
• Crayfish mate in the fall.
• The male transfers its sperm to a receptacle in the body of the female using reproductive swimmerets.
• The female stores the sperm until she lays her eggs in the spring. 
• The fertilized eggs are then attached to swimmerets for development. They hatch within 5-6 weeks.
• During the first year, crayfish molt seven times. After that, twice a year for 3-8 years until they die.