chapter 16 mammals. animals-vertebrates-mammals on the fifth and sixth days of creation god created...
TRANSCRIPT
Chapter 16
Mammals
Animals-Vertebrates-Mammals
On the fifth and sixth days of creation God created a new kind of being: “the moving creature that hath life.” Genesis 1:20
Genesis 1:20-25 describes the two main attributes of the animal kingdom: mobility and diversity.
Mobility and Diversity
Animals are living organisms that move from place to place in their environment, mainly for the purpose of obtaining food.
Most animals are motile – they move from place to place.
Some animals are sessile – they are stuck in one place, but are able to move food toward themselves.
Mobility and Diversity
There are over one million known and classified species of animals alive today.
Symmetry in the Animal Kingdom
Three types of symmetry:
1. Bilateral – organism can be cut in half and be the same on both halves
2. Radial – cut in half in many ways and all the halves will be the same
3. Asymmetry – changing shape constantly – no symmetry
Vertebrates: Animals with Backbones
Zoology is a broad study that is divided into smaller parts…
two of these parts are:1. vertebrates – animals with
backbones2. invertebrates – animals without
backbones
Vertebrates make up only 3% of all animals and include: mammals, birds, reptiles, amphibians, and fish
Characteristics of Vertebrates
• Endoskeleton – made of bone or cartilage
• Tetrapods – most have four appendages
• Bilateral symmetry
• Phylum Chordata – modern evolutionists place vertebrates into this larger group.
Mammals
• Warmblooded • Hair• Mammary glands (produce milk)• Lungs• Four-chambered heart• Most are born alive• Most have two pairs of limbs and seven
neck vertebrae
Mammals
Mammals have many characteristics in common, but there are differences in structure of the design.
Example: Elephants have incisors, but they take the form of tusks.
Temperature Regulation• Animals are classified as either warmblooded or
coldblooded.• A warmblooded animal does not necessarily
have warmer blood than a coldblooded animal.• The difference?
a warmblooded animal regulates its temperature by internal mechanisms
a coldblooded animal must regulate its temperature by external mechanisms
• All mammals are considered warmblooded.
Temperature Regulation
• Homeothermic – warmblooded animals are able to maintain the same temperature
• Hibernation – small animals like squirrels cannot gather enough food in the winter to maintain warmth and so will hibernate.
if disturbed they will not wake up• Winter Sleep – larger animals like bears sleep in
the winter to maintain warmthif disturbed they will wake up
Mammals and Nature
• Mammals are important to man as helpers and food.
• Mammals are important to nature in that they keep a balance in population of animals and plants.
• Carnivores prey upon herbivores and thus keep plant populations from dwindling.
Mammal Reproduction
• Fertilization – mammals reproduce by sexual fertilization
• In sexual reproduction a reproductive cell from a male unites with a reproductive cell of a female.
• The male cell (a sperm) is produced in the organ called testes.
• The female cell (an egg) is produced in the organ called ovaries.
Mammal Reproduction
• The eggs enter a tube called the oviduct
it is here where fertilization takes place
• Some mammals like cats and dogs release several eggs for fertilization, others like horses generally only one.
Mammal Reproduction
• Cell Division
- The oviduct leads to a organ called the uterus
- in the uterus the fertilized egg (now already several cells large) attaches to the wall via a placentia
Mammal Reproduction
Embryonic Development At the time of attachment the developing
mammal is now called an embryo.
The embryo forms three layers called primary germ layers:1. Ectoderm – Outer layer – will specialize into the
nervous system, sensory organs, and skin.2. Mesoderm – middle layer – will specialize into muscle,
bone, blood, lymph vessels, reproductive organs, and kidneys.
3. Endoderm – inner layer- will specialize to become the digestive system, respiratory tract, urinary bladder, and urethra.
Mammal Reproduction
• The embryo grows and develops nourished by the placenta and surrounded by amniotic fluid for protection.
• Once the embryo is recognizable it is called a fetus.
• The entire time from fertilization and birth is called the gestation period.
for hamsters a period of 16 daysfor elephants a period of 2 years!
Mammal Reproduction
• At birth the umbilical cord will be cut by the mother freeing the newborn from the mother.
• Mammals that then nourish their young during development are called viviparous.
Mammal Reproduction
Non-placental mammals two orders of mammals are not nourished thru a
placenta1. Monotemata
young are expelled in an egg-like shell.these oviparous mammals do not bear live
young.Examples: duckbill platypus – the babies lap up
milk from the mother.2. Marsupials
Young attach to the mother in a pouchExample: kangaroos, opposums
Three Major Categories of Mammals
Based upon the way the developing young are nourished:
1. Placental mammals
2. Egg-laying mammals
3. Pouched mammals
The Mammalian Orders
There are about 20 mammalian orders comprising 4000 species…
Order Tububildentata
Contains only one species: The aardvark
designed for two things:
digging holes and eating termites and ants
Order Proboscidea
Only two species:African elephants and Asian elephants
They are the largest living land mammal, but there are over 300 species in fossils
Elephants are herbivores and a bull male can eat 300 lbs of food a day!!
Order Proboscidea
Tusks are made from ivory and are enlarged incisor teeth.
Their teeth wear down over time, but are replaced 5 times over their lifetime.
Order Sirenia
• Often called “sea cows”• Include manatees and
dugongs
• Dugongs live in smaller seas like the red sea
• Manatees are larger and live in larger coastal waters around the Caribbean and Florida.
Order Monotremata
• The only oviparous (egg-laying) mammals in existence
• Includes the echidna (spiny anteater) and the duckbill platypus
• Both only live in Australia, New Guinea, and Tasmania
Order Edentata
• Armadillos, Sloths, and Anteaters
Order Pholidota
• Pangolins (scaly anteater)
• Live in southeast Asia, Indonesia, and parts of Africa south of the Sahara
Order Marsupialia
• The pouched mammals
• Includes kangaroos, opossums, wombats, koalas, and numbats
Order Insectivora
• Includes 300 species• Includes shrews,
hedgehogs, and moles
• The smallest mammal is believed to be the pigmy shrew.
Order Chiroptera
• The flying mammals – bats
• Echolocation system: Contrary to popular opinion, bats can see very well…but they also have a sonar system to locate insects.
• Scientist think that this system is so unique that the bats are able to actually create a mental picture of the insect.
Order Chiroptera
• In the summer in Bracken Cave near San Antonio, Texas, the 20 million bats that live there consume 250 tons of insects every night.
Order ChiropteraBats
• Behavioral Characteristics: - Bats are timid and do not generally attack
people - Some bats are fruit eaters - Bats are nocturnal - Bats in cold regions are known to spend
longer periods of time in hibernation than any other mammal
- vampire bats do drink blood, but it is the blood of cattle – the only danger to the livestock is the rabies virus that many bats carry
Order Cetacea
Marine Mammals:
Includes: Baleen whales – they sift their food
Blue whales – largest animal
Sperm whale and killer whale – both have teeth
Dolphins – use echolocation
Order Cetacea
This order gives birth to live young.
The whaling industry in the United States ceased in 1971.
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Order Primata
Tree Dwelling Mammals
Includes 166 species…monkey, apes, chimpanzees, orangutans, gibbons, and gorillas...lemurs and others…
Order Primata
Apes: Primates without tails…
The largest is the mountain gorilla of the volcanic mountain ranges of East Africa (Congo)
The smallest ape is the gibbon.
Considered the most intelligent is the chimpanzee…
Order Primata
Monkeys
Monkeys are divided into two groups…New world and old world monkeys.
New world monkeys live in the tropical forests of Central and South America as well as Africa and Asia
They possess a prehensile tail (a tail for grasping objects)
They include spider monkeys and howlers as well as others…
Order Primata
Monkeys
Old world monkeys are noted for their close nostrils.
They live in Africa and Asia only…
They include colobus monkeys, baboons
They mostly eat leaves…
Order Primata
Lemurs:
Live only in one area – Madagascar
They eat some insects as well as leaves, fruit, and bark
Order Rodentia
Gnawing Mammals
1700 species…Including: mice, rats, capybara,
squirrels, woodchucks, gophers, beavers, porcupines…
There are more rodents than there are all other mammals combined.
Order Rodentia
Mice: mice are the most prolific animal…they produce 5 or more litters of 3 to 12 young every year..
Rats: rats are aggressive…they are impossible to kill off…if their numbers become low, the survivors become stronger and more productive
rats are a great health concern as they carry many diseases (plague, food poisoning, and typhus)
Order Rodentia
Woodchucks (groundhog): make tunnels and mounds several feet high.
Beavers: largest rodent in U.S…have been known to build dams up to 2300 feet wide.
Porcupines: even with their barbs, they are still preyed upon by carnivores and owls.
woodchuck
Order Dermoptera
Flying lemers
Found in Malaysia, Thailand, Borneo, Java, and the Philippines.
The longest gliding mammal.
Order Lagomorpha
Hare-like mammals:
Have four upper incisors…
Includes rabbits, hares, and pikas
Order Hyracoidea
This order includes only the hyrax…
It is mentioned in the Bible…Proverbs 30:26.
They have hoofs on their toes and pads on the sole of their feet.
They are defenseless and live in rocky terrains for protection.
Order Perissodactyla
Odd-toed hoofed mammals
Hoofed animals are called ungulates.
Includes rhinoceros, tapirs, horses, zebras, and donkeys
Most ungulates have been designed as swift runners, because they need to escape from predators.
Order Artiodactyla
Even-toed hoofed animals
There are 171 species of even-toed ungulates.
Many either have antlers or horns…
They include cattle, buffalo, sheep, goats, and antelope – with horns
and deer – with antlers
It also includes the giraffe.
Order Artiodactyla
This order is the most important on the earth, providing a link between man’s use and also the use by a number of flesh eating animals.
Order CarnivoraFlesh eaters!!!!
Carnivores lead a more active life than herbivores.
There are over 200 species of carnivores.
Includes bears, cats, dogs, foxes, raccoons, weasels, seals, walruses, sea lions, pandas, skunks, badgers, otters, mongooses, civets, and hyenas.
Carnivores eat herbivores and lack a complex stomach.
Carnivores eat separate meals and have time in between to play, explore, and develop their hunting skills.
Order Carnivora
Bears
Bears are actually omnivores – they eat plant and meat
The Alaska brown bear (Kodiak bear) is the largest bear – they are a type of grizzly bear.