1. Comparing Invertebrates
Chapter 29

3. 29-1 Invertebrate evolution
Key Vocab:
Invertebrate
Radial Symmetry
Bilateral Symmetry
Cephalization
Coelom
Trace fossil
Deuterostome
An animal that does not have a backbone, or vertebral column
Bill Nye Video

4. Treasure troves of invertebrate fossils, dating between 575 and 543 mya have been discovered in the Ediacar Hills of Australia and in Chengliang, China
Echinoderm
Cnidaria or Echinoderm?
Triradial?

5. Origin of the Invertebrates
Trace fossils were discovered, dating invertebrates million years old
Trace Fossils are more common than body fossils
because all living things leave traces.
Trace fossils give us proof of animal life from the past.
Trace fossils include things like foot prints,
burrows, and fossilized feces.

6. The First Multicellular Animals
The Ediacaran fossils include some of the earliest and most primitive animals known

7. Edicarian Fossils Most animals were flat, platelike
Absorbed nutrients from the surrounding water
Some may have been photosynthetic
Were segmented and had bilateral symmetry
Probably simple with little internal organization

8. Beginnings of Invertebrate Diversity
Cambrian Period: 544 mya is marked by an abundance of different fossils
By the Cambrian Period, some animals had evolved shells, skeletons, and other hard body parts—all of which are readily preserved in fossils
The Burgess Shale fossils show diversity
not seen previously
Cambrian Explosion: the ancestors of most modern
Animal phyla first appeared in the fossil record

9. Burgess Shale Fossils
Typically had body symmetry, segmentation, some type of skeleton, a front and a back end, and appendages adapted for many functions.

10. Invertebrate Phylogeny

11. Review
Which period is marked by such diversity it is referred to as an “explosion”
A) Ediacaran
B) Cambrian
C) Cryogenian

12. Review
Animals of the Cambrian period typicaly had all of the following except…
Body symmetry
Segmentation
Some type of skeleton
A backbone

13. review The Burgess shale fossils are in Texas Arizona New York Canada
Footprints, burrows and fossilized feces are
A) resin fossils
B) psuedofossils
C) trace fossils
D) imprints
The Burgess shale fossils are in
Texas
Arizona
New York
Canada

14. Evolutionary Trends Specialized cells, tissues and organs
Body Symmetry
Cephalization
Segmentation
Coelom Formation
Embryological Development

15. Specialized Cells, Tissues, and Organs
Specialized cells joined together to from tissues, organs and organ systems that work together to carry out complex function

16. Body Symmetry Sponges lack symmetry. All others exhibit some type
Radial Symmetry; body parts extend from the center of the body
Bilateral Symmetry; have mirror-image left and right sides

17. Cephalization
The concentration of sense organs and nerve cells in the front of the body
Invertebrates with cephalization can respond to the environment in more sophisticated ways than can simpler invertebrates

18. In most worms and arthropods, nerve cells are arranged in structures called ganglia. In more complex, nerve cells form an organ called a brain

20. Coelom Formation A coelom is a fluid-filled body Cavity lined with
mesoderm
Acoelomates do not have a coelom.
Pseudocoelomates have a partial coelom.
Coelomates are the most complex and have a coelom.

21. Review Which of the following lacks symmetry? (asymmetrical)
A) a sea anemone
B) a grasshopper
C) a crayfish
D) a sponge

22. review
The concentration of nerve cells and sense organs in the anterior end of an organism is
A) coelomization
B) radial symmetry
C) cephalization
D) asymmetry

23. Segmentation
Over the course of evolution, different segments have often become specialized for specific functions
Same structures are repeated in each body segment
Also allows a animal to increase in body size with a minimum of new genetic material

24. Embryological Development
In most invertebrates, the zygote divides to form a blastula
Protostomes: the blastopore becomes the mouth
Dueterostomes: the blastopore becomes the anus

25. Review An acoelomate is an animal that has
A body cavity lined with endoderm and ectoderm
A body cavity partially lined with mesoderm
A body cavity completely lined with mesoderm
No body cavity between their germ layers.

26. Review Cephalization refers to
Division of the body into upper and lower sides.
Concentration of sense organs and nerve cells in the front of the body
Joining together of specialized cells to form tissues
Formation of a body cavity between the germ layers

27. Review
The classification of an animal as a deuterosome or a protosome is based on
Its body symmetry
Whether or not it has a coelom
What happens to the blastopore
The number of germ layers it has

28. review The area marked ?????? is called the… Endoderm Coelom Protosome
???????????
The area marked ?????? is called the…
Endoderm
Coelom
Protosome

29. Video
Octopus
Sea cucumber
Sea Anenome
Deadly shrimp
What are Inverts?

30. 29-2 Form and Function in Invertebrates
Key Vocab
Intracellular Digestion
Extracellular Digestion
Open Circulatory System
Closed Circulatory System
Hydrostatic skeleton
Exoskeleton
Endoskeleton
External fertilization
Internal fertilization

31. review
The diversity of invertebrate phyla underwent its greatest increase
Before the Cambrian period
During the Cambrian period
After the Cambrian period
Both before and after the Cambrian period

32. review A body cavity that forms between the germ layers is called a(n)
Coelom
Blastopore
Mesoderm
Ectoderm

33. To survive, all animals perform the same essential tasks:
Bill Nye
To survive, all animals perform the same essential tasks:
Feeding and digestion
Respiration
Circulation
Excretion
Response
Movement
Reproduction

34. Feeding and Digestion Intracellular Digestion Extracellular Digestion
Before food can be used for energy, the food must be broken
down, or digested
Intracellular Digestion
Food is digested inside cells
Extracellular Digestion
Food is broken down outside the cells in a digestive cavity or tract and then absorbed into the body

35. Patterns of Extracellular Digestion
Simple animals such as cnidarians and most flatworms ingest food and expel wastes through a single opening.
Food is digested in a cavity through both intracellular and extracellular means
Some cells secrete enzymes and absorb digested food
Other cells surround particles and digest them in vacuoles
Nutrients diffuse to cells throughout the body

36. More complex animals digest food in a tube called a digestive tract.
Have a mouth and an anus

37. Respiration
All animals must exchange Carbon dioxide and oxygen with the environment
The larger the surface area, the greater the amount of gas exchange.
For diffusion to occur, the respiratory surfaces must be moist.

38. Aquatic Invertebrates
Larger invertebrates use feathery structures called gills for respiration
Small invertebrates like cnidarians and flatworms diffuse gases through their tissues

39. Terrestrial Invertebrates
Respiratory surfaces are covered with water or mucus to minimize water loss
Several types of respiratory surfaces
Mantle cavity; land snails
Book lungs; spiders
Spiracles and trachea; insects

40. Circulation
All cells of multicellular animals require a constant supply of oxygen and nutrients
Very simple organisms: diffusion
More complex have some type of pumping mechanism (heart) and vessels

41. Two types of Circulatory Systems
Open circulatory system
Blood is only partially contained within a system of blood vessels
Blood fills sinuses and is in direct contact with tissues

42. Closed Circulatory System
A heart or heartlike organ forces blood through vessels that extend throughout the body
Blood can be circulated more efficiently

43. Review
The distinguishing feature of a closed circulatory system is that
Its does not include a heart
Blood in contained within vessels that extend throughout the body
Blood is kept at low pressure
Blood is circulated with less efficiency than in an open circulatory system

44. review In a protosome, the blastopore becomes a(n) Mouth Anus Zygote
Blastula

45. Excretion
Multicellular animals must control the amount of water in their tissues.
Must get rid of ammonia
Flat worms use flame cells to get rid of excess water
Terrestrial conserve water and get rid of ammonia as urea excreted in urine that was formed in nephridia
Some insects and arachnids have Malpighian tubules

47. Sexual and Asexual Reproduction
Most invertebrates reproduce sexually during at least part of their life cycle.
Fusion of gametes; genetic variation
Many also reproduce asexually
Allows the ability to reproduce rapidly when environmental conditions are favorable

48. Sexual reproduction
External fertilization: eggs are fertilized outside the female’s body
Internal fertilization: eggs are fertilized inside the female’s body

49. reveiw Which structures are NOT part of an excretory system?
Flame cells
Spiracles
Malpighian tubules
nephridia

50. review Which statement refers to sexual reproduction?
All offspring are genetically identical to the parent
Offspring are produced from the fusion of male and female gametes
AN organism breaks into pieces that grow into new individuals
New individuals are produced from outgrowths of parent’s body wall

51. review During development, a zygot divides repeatedly to form a (n)
Endoderm
Endoskeleton
Blastula
Germ layer

52. Response Three trends in the evolution of the nervous system
Centralization; nerve nets consist of individual nerve cells that form a netlike arrangement
Cephalization; concentration of nerve tissue and organs in one end of the body
Specialization; sense organs that detect light, sound, chemicals, movement, and even electricity to help them discover what is happening around them

53. Movement aNd support Muscles work with some type of skeletal system
Hydrostatic skeletons: muscles surround a fluid- filled body cavity that supports the muscles.

54. Endoskeleton: structural support inside the body
Calcified plates inside echinoderms

55. Exoskeletons: Hard body covering made of chitin
Jointed in arthropods, shells in mollusks

56. review An endoskeleton is a Shell of a mollusk
Fluid-filled body cavity that supports the muscles
Structural support located inside the body
Hard body covering made of chitin

57. review
An example of an invertebrate with a hydrostatic skeleton is a(n)
Spider
Sponge
Sea star
earthworm