Invertebrates

1. Invertebrates

2. What is an Animal? • We take it for granted that animals are things that are fuzzy, furry and we can pet • However to really understand what animals are, we have to have a broad definition of animals and an open mind • Not all animals fit the 3rd grade idea of an animal

3. What is an Animal? • Animals are… • Multicellular • Heterotrophs • Eukaryotic • Obtain nutrients through ingestion • Multicellular – Many Cells • Heterotrophic – Other Feeding • Eukaryotic – True Nut • Ingestion – Process of Eating

4. What is an Animal? • Also animals have a few other fun features • Distinctive cell organelles • No cell walls • Held together by collagen • All of these factors are things that make animals unique

5. Animal Development • The process of reproduction is similar to most animals as well • Adults produce the gametes eggs or sperm through meiosis • Eggs and sperm combine to create a zygote • A zygote is a single cell created from the fusion of egg and sperm

6. Animal Development • The zygote starts to undergo mitosis • This happens rapidly and the number of cells starts to grow • The cells then form a blastula • A blastula is a ball of cells that is typically hollow

7. Animal Development • Once the blastula has formed one of the sides starts to fold into itself • When this happens the group of cells is called a gastrula • The inner folds are called the endoderm • They will form the digestive tract

8. Animal Development • The cells that remain on the outer layer are called the endoderm • They will eventually form the outer coverings of the animal • They can also form some nervous organs

9. Animal Development • The cells that are trapped in between the two layers are called the mesoderm • These will form most of the internal organs of the animal

10. Animal Development • After the gastrula stage, many animals develop to adults • However not all animals are the same • Some animals develop into a larval stage • These animals will have to undergo metamorphosis later in life to reach an adult form

11. Body Plans • Animals can be characterized by their body plans • This means the makeup and location of their major parts, organs and brain • Based on how organisms are laid out, we can tell a large amount about their history

12. Body Plans • Symmetry plays a portent role in describing body plans • Symmetry is a mathematical patterned self similarity • Types of symmetry are important to understanding body plans

13. Body Plans • Radial symmetry is when an organism is symmetric on a central body part • All parts would be symmetrical if you used a pizza cutter • Bilateral symmetry is when an organism’s halves are symmetrical • All parts would be symmetrical if you used a buzzsaw

14. Body Plans • To define symmetry we have to define the surfaces of an organism • Anterior – Refers to an organisms head • Posterior – Refers to an organisms tail (end) • Dorsal– Refers to an organisms back • Ventral – Refers to an organisms bottom (stomach)

15. Space – The Biological Frontier • Take your hand and poke your partner’s (or your own if they object) belly • What do you feel? • Is there a strong muscle that goes from ventral to dorsal? • What makes up that area?

16. Space – The Biological Frontier • Organisms can have a body cavity… or not • A body cavity is a fluid filled space between the outer digestive tract and the body wall • Not every organism has a body cavity

17. Space – The Biological Frontier • If there is a fluid filled space between the body wall and the inner digestive tract it is called a hydrostatic skeleton • This enables a greater range of movement for the organism and cushions and protects the inner organs

18. Taxonomy • Once you understand how organisms are built and develop we can define which ones are related • Remember, a biological family tree is called a phylogenetic tree

19. Taxonomy • Today we will be studying the different groupings of invertebrates • Invertebrates lack a spinal column • This does not limit their complex nature or their role in the environment

20. Sponges • Sponges are organisms that have a simple porous body • Considered the most simple organisms • Contain no muscles or nerves • Some are radially symmetric, however most have no major body plan

21. Sponges • https://www.youtube.com/watch?v=BW05vMziy2o

22. Cnidarians • One of the oldest invertebrates • Includes hydras, sea anemones, corals and jellies (aka jellyfish) • They have radial symmetry • They are all carnivores • They use complex nematocyststhat sting prey

23. Cnidarians • They have two major body types • A polyp is fixed on one end with extending tentacles • A medusa is a free moving form of the cnidarian that can move with or against the tide

24. Cnidarians • http://shapeoflife.org/video/behavior/cnidarians-anemone-catches-goby

25. Platyhelminthes • This consists of the flatworms • They are worms… that are flat • Have a gastrointestinal system with only one opening • Due to their nature they need to be in water or damp envrionments

26. Platyhelminthes • Free-living Flatworms live under rocks and have light sensitive eyecups • Flukes live as parasites and can utilize multiple hosts • Tapeworms are intestinal parasites that have no digestive tract

27. http://videos.howstuffworks.com/discovery/42160-monsters-inside-me-japanese-lung-fluke-video.htmhttp://videos.howstuffworks.com/discovery/42160-monsters-inside-me-japanese-lung-fluke-video.htm • http://www.mirror.co.uk/tv/tv-news/infected-video-bbc-presenter-infected-3094743

28. Nematodes • Nematodes are also called roundworms • This is because they are round… and worms • They have bilateral symmetry and they have a false body cavity • They have a mouth at the blunt end of the body • They also have a tough outer coat called a cuticle

29. Nematodes • Nematodes are the first organisms that have a one way digestive tract • Many nematodes have a function as detritus feeders • Some nematodes are parasites and can be dangerous

30. Nematodes • Has a true body cavity • They have an opencirculatory system • This means that organs are bathed directly in blood • Their body has one small brain with nerve clusters in each segment • Their body has a large pumping organ in front and behind the body

31. Video • A real life heartworm extraction • Warning (Not for everyone) • https://www.youtube.com/watch?v=phCod-0tfkE

32. Annelids • Annelids are segmented worms • This means they are worms … that have segments • Its body is segmented into a region of repeating parts • Each part is designed to function and move on its own • Greatly increases the flexibility and speed of the organism

33. Annelids • Earthworms are the most commonly found in damp soils • The polychaetes are mostly marine and they are distinct for their “hairy” and feathery appearance • Leeches are carnivores or parasites that are mostly in freshwater, salt water or live in trees

34. Molluscs • Molluscs are composed of organisms that have a soft body, but most have a hard shell • Snails, slugs, oysters, clams, octopus, squids and cuttlefish are all molluscs • This really large and wide range of organisms is all in the same family • Most only have a few common features, but differ greatly

35. Molluscs • The three main parts of the mollusc are… • A muscular foot which aids movement • A section of visceral mass which contains most organs • A mantle which is a fold of tissue that secretes a shell

36. Molluscs • The gastropods are the largest group of molluscs • Gastro (belly) and pod (foot) • These organisms mostly have spiraled mantles that create spiraled shells • The bivalves are composed of clams, muscles and oysters • Bi (two) and valva (hinged door) • They often live on underground structures or in sediments

37. Molluscs • Cephalopods are adapted to be fast and agile predators • Kephale (head) pod (foot) • They have a small internal shell or it is absent • They have a beak that is used for tearing apart food

38. Arthropods • Over a million species of arthropods exist • This makes them the most species successful animals in the world • There are over 10^18 arthropods on the earth • That is over a billion billion arthropods on the earth

39. Arthropods • Arthropods have a few key features • Arthropods have an exoskeleton that protects them • Arthropods have segments of a head, thorax and abdomen • Arthropods also have jointed appendages

40. Arthropods • Chelicerates are organisms that live in the ocean • It only has one member, the horseshoe crab • It is considered a living fossil

41. Arthropods • Millipedes ad Centipedes have many segments • Centipedes have carnivores that have poison claws and one pair of legs per segment • Millipedes have two legs per body segment

42. Arthropods • Crustaceans are nearly all aquatic • Lobsters, crabs, shrimp and crayfish are easy to identify • However barnacles find themselves in this group as well

43. Arthropods • Insects are by far the largest of the arthropod group • They make up large number of the species that make up the earth • They undergo multiple life stages with most insects undergoing a complete metamorphosis • This means they have a larva, pupa and adult life stage