Circulatory Systems Move Nutrients, Gases and Other Materials

1. Circulatory Systems Move Nutrients, Gases and Other Materials • Two basic types: • Open system: • Blood periodically leaves the blood vessels, bathes the tissues, and is recollected into the vessels. • Found in arthropods • Closed system: • Blood never leaves the blood vessels • Found in humans and other animals

2. Circulatory Systems Move Nutrients, Gases and Other Materials • Circulatory systems have three main components: • Vessels • Blood • Hearts • Each evolved from rather simple components in primitive worms to highly complex ones found in chordates.

4. Animals Must Maintain Proper Water Balance • For all cells, water is a precious necessity. • It is necessary to maintain the appropriate concentrations of solutes in an organism’s body • Solute concentrations can be different from those found in body compared to the environment. • Need to have an ability to regulate the solute concentrations due to these differences.

5. Animals Must Maintain Proper Water Balance • Fish living in hypertonic environment: • Drinks water. • Loses water through the gills. • Loses solutes in urine and active transport through the gills.

6. Animals Must Maintain Proper Water Balance • Fish living in hypotonic environment: • Drinks no water. • Water absorbed by osmosis through gills and body surfaces. • Solutes absorbed by active transport at gills.

7. Animals Must Maintain Proper Water Balance • Terrestrial animals have 5 ways to reduce water loss: • Live in moist environment • Live in habitat with high humidity • Be active at night when humidity is the highest • Special body coverings to prevent water loss.

8. Animals Must Maintain Proper Water Balance • Terrestrial animals have 5 ways to reduce water loss: • Organisms living in the desert have special mechanisms for reducing water loss in feces and concentrating wastes in urine

9. Organisms Must Get Rid of Metabolic Wastes • Cellular metabolism produces waste compounds that must be disposed of. • Example: Ammonia • Animals evolved a number of different excretory systems • Blind tubes that collect waste to more complex organs such as kidneys.

11. How Do Organisms Move? • External environments are challenging. • Four options for dealing with challenges: • Isolate themselves • Seek shelter • Adjust to changing conditions • Move to more favorable environments

12. Microbe Movement • Thick cell walls and shells protect many microbes from potentially hostile environments. • Microbes can move using flagella, cilia, and pseudopodia (false feet)

13. Animal Movement • Involves the interactions between muscles and their shells or skeletons • Among animals, there exist 3 types of skeletons: • Hydrostatic • Exoskeleton • Endoskeletons

14. How Do Organism Reproduce? • Purpose of life is to reproduce • Because life can only persist through reproduction • Two types • Asexual • Binary fission or mitosis • Sexual

15. Most Common Form of Reproduction is Asexual • Process of one cell becoming two • Binary fission occurs in prokaryotic cells • Mitosis occurs in all others • Also allows for tissue repair

16. Asexual Reproduction

17. Sexual Reproduction Evolved Among Bacteria, Protists and Fungi • Conjugation • Cytoplasmic bridge (pilus) develops between two individuals allowing one-way exchange of genetic material.

18. Sexual Reproduction Among Eukaryotes • Follows three general types: • Diploid cycle: • Seen in all animals and some protists. • All cells of the organism are diploid except for gametes. • Gametes remain single-celled, haploid entities until fertilization.

19. Sexual Reproduction Among Eukaryotes • Follows three general types: • Haploid cycle: • Seen in all fungi and some algae. • All cells of the organism are haploid. • Budding and other types of asexual reproduction produce haploid individuals. • When reproduce sexually, cells merge, fuse nuclei, and become diploid. • Immediately undergo meiosis producing haploid spores

20. Sexual Reproduction Among Eukaryotes • Follows three general types: • Alternating cycle: • Seen in all plants and some algae • Has two distinct generations • Haploid gametophyte that produces gametes. • Diploid sporophyte that produce spores.

21. Sexual Reproduction in Water is Relatively Easy • Aquatic organisms spew gametes into the environment • Gametes must find each other so fertilization can occur • Timing of gamete release is important

22. Sexual Reproduction in Water is Relatively Easy • Simultaneous release of gametes is important. Two reasons: • Facilitates fertilization. • Foils predators by “flooding the market”.

23. Sexual Reproduction in Water is Relatively Easy • Less danger of gametes drying out. • Less protected. • Eggs have less yolk than those that reproduce on land.

24. Many Animals Successfully Reproduce on Land • The ability to reproduce on land apparently evolved independently among segmented worms, mollusks, arthropods and chordates. • Each group originated in the ocean and evolved successfully in different environments until they became terrestrial organisms.

25. Many Animals Successfully Reproduce on Land • Transition from water to land is seen most dramatically by comparing their eggs. • Marine fish have little yolk and no shells. • Eggs of freshwater fish amphibians, which reproduce in nutrient-poor environments, have considerable more yolk and are surrounded by slime layers.

26. Many Animals Successfully Reproduce on Land • Eggs of reptiles, birds, and primitive mammals are the largest known, contain relatively huge amounts of yolks.

27. Many Animals Successfully Reproduce on Land • The eggs of advanced mammals have no shells and no yolk. • Offspring are retained within the female’s body (marsupials) where they are protected and nourished.

28. After Fertilization, Organisms Develop and Grow • Pattern of embryonic development has three general phases. • First phase: fertilized egg undergoes mitosis which increases the number of cells little or no overall growth in size.

29. After Fertilization, Organisms Develop and Grow • Second phase: • Involves the early appearance of organ system. • Third phase: • Further refinement of organ systems and significant growth.

30. Animal Development

31. Two patterns of post-hatching and development in birds • 1. Hatchlings are virtually helpless and totally dependent on parents for food and protection. • 2. Hatchlings can find their own food and partially protected from the environment by downy feathers.

32. Mammals Development • Mammals are helpless at birth and totally dependent on adults for nourishment and protection • Initial nourishment provided by mammary glands. • Following weaning, young are still dependent on adults for food. • Need to learn where to seek food and shelter, how to avoid predators from associations from parents and adults.