Chapter 33-34 : Protostomes and Deuterostomes

List the two groups that all protostomes belong to

Lophotrochozoa and Ecdysozoa

List the characteristics for the Lophotrochozoa

• trochophore - a free-living larva

• Lophophore - a horseshoe-shaped crown of ciliates tentacles surrounds the mouth used in filter-feeding

List the characteristics for Ecdysozoa

• Contains animals that moult due to a hard exoskeleton

• Two groups - Arthropods and Nematodes

Protosomes

Develop the mouth first from or near the blastophore

Deuterostomes

Develops the anus first from the blastphore

Name two phyla of deuterostomes

Phylum Echinodermata and Chordata

List characteristics of the phylum Echinodermata

• exclusively marine

• Endoskeleton

• Pentaradial symmetry

What defines the oral surface of the phylum Echinodermata

Mouth

What is important to note abut the symmetry found in phylum Echinodermata

Pentaradial as an adult, bilateral as larva and all systems are organised with branches radiating from the centre.

What is the epidermis that covers the endoskeleton of the phylum Echinodermata made of?

Calcium carbonate plates called ossicles

What is meant by the endoskeleton of the phylum Echinodermata

The ossicles may be tightly or loosely joined and all members have mutable collagenous tissue

How do the organisms of phylum Echinodermata reproduce

• Some reproduce asexually by splitting ( ability to regenerate)

• Most reproduce sexually by releasing gametes ( Gonochoric) into the water, free-swimming larvae, each class has a characteristic type of larva

List the 5 extant classes of phylum Echinodermata

• Class Asteriodea

• Class Echinoidea

• Class Ophiuroidea

• Class Crinoidea

• Class Holothuroidea

What class do star fishes belong to

Class Asteroidea

What class do sea urchins belong to

Class Echinoidea

What class do Brittle stars belong to

Class Ophiuroidea

What class do Sea lilies belong to

Class Crinoidea

What class do Sea cucumbers belong to

Class Holothuroidea

What 4 features characterise the phylum Chordata and play an important role of the evolution of the phylum

• Nerve cord - just beneath the dorsal surface of the animal and differentiates into the brain and spinal cord

• Notochord - may be replaced by vertebral column

• Pharyngeal slits - pharyngeal pouches present in all vertebrate embryos

• Postanal tail - extends beyond the anus

What are somites

Chordate muscles that are arranged in segmented blocks

What are the names of the three subphyla of phylum Chordata

• Urochordata

• Cephalochordata

• Vertebrata

What are the characteristics of subphylum Urochordata?

• Marine animals ( e.g Tunicates and salps )

• Larvae have notochord and nerve cord

• Adults usually lose the tail and notochord

• Many secrete a tunic ( cellulose sac) that surrounds the animal

What are the characteristics of the subphylum Cephalochordata

• Notochord is persistent throughout the organisms life but they have no distinguishable head

• Spend most of their time partly buried

• Feed on plankton using cilia-generated currents

• Closest relatives to vertebrates, e.g Lancelets are scaleless chordates

How do vertebrates differ from non-vertebrates within the phylum Chordata

• have a spinal column

• Vertebral column - encloses and protects the dorsal nerve cord

• Head is distinct and well-differentiated possessing sensory organs

What are characteristics of the subphylum Vertebrata

• Neural crest - unique group of embryonic cells that form many vertebrate structures

• Internal organs - liver, kidneys, endocrine glands, heart with a closed circulatory system

• Endoskeleton - made of cartilage or bones making great size and lots of movement possible

When birds and mammals become dominant

After the Cretaceous mass extinction

What are characteristics of fish ( most diverse and over half of all vertebrates ) in the subphylum Vertebrata

• vertebral column

• Jaws and paired appendages

• Internal gills

• Single-lop blood circulation

• Nutritional deficiencies

Which organism in the subphylum Vertebrata provided evolutionary base for invasion of land by amphibians

Fish

What are significant adaptations that occurred in bony fish

• swim bladder - gas-filled sac to regulate their buoyant density

• Gill cover - the operculum covers the gills and functions by permitting water pumping over gills which is efficient when organism is stationary

How is the swim bladder in bony fish able to control a fish’s buoyancy and how it functions

Gas is taken from the blood and the gas glan secretes gases into the swim bladder. Then from the bladder the gas is released by a muscular valve, the oval body

What are the 2 major groups bony fish

• Ray-finned fishes - class Actinpterygii

• Lobe-finned fishes - class Sarcopterygii

What are the major differences between The two major groups of bony fish

• Ray-finned fishes - parallel bony rays support and stiffen each fin, there are no muscles in the fins

• Lobe-finned fishes - paired fins that have a long fleshy muscular lobe, supported by central core of bones with fully articulated joints and almost certainly amphibian ancestors

What are the adaptations required for a life in a terrestrial environment

• legs to support the body’s weight

• Lungs to extract oxygen form air

• Redesigned heart and circulatory system to drive larger muscles

• Reproduction still in water to prevent egg drying

• System to prevent whole body desiccation

What are the amphibian adaptions for a life in a terrestrial environment

• legs adaptation to life on land

• Lungs

• Cutaneous respiration - supplement lungs

• Pulmonary veins - separate pulmonary circuit allows for higher pressure blood to tissues

• Partially divided heart - improves separation of pulmonary and systemic circuits

What fossil shows the transition from an aquatic environment to a terrestrial environment

Tiktaalik is the transitional fossil that is found between a fish and Ichthyostega. It has gills and scales like a fish but a neck, shoulder and the end of its limbs were a lobed fin f an amphibian.

What amphibian evolved from lobe-finned fishes

Ichthyostega

List specific characteristics of reptiles that allow them to live in a terrestrial environment

• amniotic eggs - watertight

• Dry skin - covers body to prevent water loss

• Thoracic breathing - increases lung capacity

What are the four membranes of an amniotic eggs and its function

• Chorion - outermost layer and allows gas exchange

• Amnion - encases embryo in fluid-filled cavity

• Yolk sac - provides food

• Allantios - contains excreted wastes from embryo

What is the significance of the development of an amniotic egg

It allowed for vertebrates to not depend on water for reproduction therefore allowing them to become terrestrial

What skull type in the class Reptilia is this and how many holes does it have

Anapsid skull - 0 holes

What skull type in the class Reptilia is this and how many holes does it have

Synapsids skull - 1 hole

What skull type in the class Reptilia is this and how many holes does it have

Diapsids - 2 holes

What were the first organisms in class Reptilia considered to be mammals and why

Therapsids because they were endotherms and may have had hair

What organism was the first land vertebrates t kill beasts their own size

Pelycosaurs

What were the first and vertebrates to be bipedal

Archosaurs which gave a rise to crocodiles, pterosaurs, dinosaurs and birds

What are 2 characteristics modern reptiles developed and hw are they important in terms of evolution

• internal fertilization - sperm fertilises egg before protective membranes are formed

• Improved circulation - oxygen is provided to the body more efficiently due to the septum in the heart extending to form a partial wall making a 4-chambered heart

What is the difference between temperature generation and regulation for reptiles from endothermic animals

• obtain heat from external sources

• Regulate body temperature by moving in and out of sunlight

What are 2 fundamental traits for all mammals

• Hair - long, keratin-rich filaments that extend from hair follicles and function in insulation, camouflage and sensory structure

• Mammary glands - females possess mammary glands that secrete milk

What are other notable features of mammals

• endothermic depends on higher metabolic rate

• 4-chambered heart

• Respiration using diaphragm

• Placenta - specialised organ that brings fetal and maternal blood into close contact

Discuss the adaption of specialised teeth in class Mammalia

• Different types of teeth are highly specialised to match particular eating habits

• Contrast carnivore teeth to herbivore teeth

Discuss the adaption of digestion of plants in class Mammalia

Herbivores rely on mutualistic partnerships with bacteria for cellulose breakdown

Discuss the adaption of development of hooves and horns in class Mammalia

• Hooves are specialised keratin pads

• Horns are bone surrounded by keratin

• Antlers are made of bone

Discuss the adaption of flying mammals ( bats ) in class Mammalia

• only mammals capable of powered flight

• Wing is a leathery membrane of skin and muscle stretched over 4 finger bones

• Navigate in the dark by echolocation

What did mammals look like during the time of the dinosaurs

Tiny, shrewlike, insect-eating, tree-dwelling creatures and may have been nocturnal due to large eye sockets

How did mammals change after the disappearance of dinosaurs

Increase in body size and major diversification during the Tertiary period

What’s re the two subclasses of mammals

• Prototheria ( most primitive ) - lay shelled eggs, only live in group is monotremes

• Theria - viviparous, 2 living groups ( Marsupials and Placental )

What is an example of a living organism in the subclass Prototheria

Monotremes which only have 3 living species - Duck-billed platypus and 2 echidna species

What is an example of a living organism in the subclass Marsupials ( pouched mammals )

Kangaroo ( isolation of Australia) and Opossum ( only North American marsupial )

What are two important features present in Primates that allow them to successfully adapt to an arboreal environment

• Grasping fingers and toes

• Binoculars vision - eyes shifted to the front of face and lets brain judge distances precisely

What are the characteristics of the group Prosimians

• Large eyes with increased visual acuity

• Most are nocturnal

• E.g Lemurs, lorises and tarsiers

What are the characteristics of the group Anthropoids

• Diurnal - changes eye design including colour vision

• Expanded brain

• Live in groups with complex social interactions

• E.g monkeys, apes and humans

What are the examples of the group Hominids

• Apes - larger brains than monkeys and lack tails

• Humans - hominins are more closely related to humans than chimps

What are 3 adaptions directly associated with bipedal locomotion in humans

• human vertebral column in more curved

• Spinal cord exits from bottom of skull

• Humans carry much of the body’s weight on the lower limbs leading to a broader pelvis

Name three characteristics associated with increased brain size in humans

• effective making and use of tools

• Refined and extended conceptual thought

• Use of symbolic language

Explain why you agree or disagree with the following statement: “ Human evolution is not a natural process anymore

I agree, this is due to the fact that in our current world, humans mold our world to reach our needs rather than changing evolutionarily in response to the environment.

Explain what is meant by the term “Human races” and discuss the validity of using skin colour to define a human race

Human race is due to the fact that humans are visually oriented and have differentiated in traits as they spread throughout the world. This term is not valid due to the constant gene flow which has prevent a subspecies of humans therefore race is only showing antagonism between genes so there is little to no differences between described races.