LIFE IN THE MARINE ENVIRONMENT SOME BASICS OF BIOLOGY

1. LIFE IN THE MARINE ENVIRONMENTSOME BASICS OF BIOLOGY

2. Characteristics of Life • Use Energy (the ability to do work) to grow • Metabolism – maintain complex chemical reactions • Homeostasis – maintain stable internal environment • Respond to stimuli – sense organs • Reproduce – pass genes on to next generation

3. Energy Utilization - Organisms take in energy and transform it to do many kinds of work. This fish obtains fuel from the sea urchin and uses energy stored in the molecules of its food to power swimming and other work.

4. Metabolism - This protein cascade is an example of the chemical reactions that take place in organisms. The product of one reaction becomes a catalyst for a second reaction.

5. Homeostasis – regulatory mechanisms maintain an organism’s internal environment within tolerable limits, even though the external environment may fluctuate. In this example, regulation of the amount of salt flowing through the seagull’s body fluids is controlled by glands on the bill that excrete excess ions.

6. Respond to stimuli – When threatened this squid will change colors in order to blend in with it’s surroundings

7. Reproduce – Organisms reproduce their own kind. Life comes only from life. This humpback whale protects its offspring.

8. I. Building Blocks of Life • Major macromolecules – composed mostly of carbon, hydrogen, oxygen, nitrogen, phosphorus 1. Water is not a macromolecule but composes approx. 2/3 of living organisms 2. Carbohydrates – sugars & starches a. Energy – energy extracted from carbs. during cellular respiration is used to produce ATP. b. Structural – cellulose, cell wall of plants; chitin, exoskeleton of insects & arthropods

9. Chitin a structural carbohydrate

10. I. Building Blocks of Life 3. Proteins – most varied & complex organic molecules a. 20 amino acids are building blocks of all proteins b. Structural proteins – found in cell membranes, muscles (actin/myosin) c. Functional – enzymes (speed up reactions but are not changed by reactions d. Chemical messengers – hormones, made in one part of the body but affect another part

11. Muscles are mostly made up of proteins.

12. I. Building Blocks of Life 4. Lipids – water insoluble, fats, oils, waxes a. Major component of cell membrane b. Energy stores c. Retards evaporation d. Buoyancy – marine mammals, birds e. Hormones – cholesterol; estrogen, testosterone

13. PhospholipidBilayer

14. Blubber

15. I. Building Blocks of Life 5. Nucleic Acids a. DNA, RNA – genetic material

16. I. Building Blocks of Life • Fuel of Life – 1. ATP – energy molecule that is used in chemical reactions 2. Photosynthesis – Fig. 4.4 – Process by which the energy from sunlight is used to covert low energy inorganic compounds to organic compounds a. 6CO2 + 6H2O  C6H12O6 + 6O2 b. Light energy (photons) are captured by photosynthetic pigments, chlorophyll a is primary pigment c. Autotrophs – make own food heterotrophs – must obtain energy from outside sources

17. Photosynthesis

18. I. Building Blocks of Life 3. Respiration - Fig. 4.6 – process in which organic compounds are broken down to in order to release energy a. C6H12O6 + 6O2 6CO2 + 6H2O + 36ATP b. Energy recycles – Fig. 4.5 i. Aerobic respiration – requires O2 ii. Anaerobic respiration – no O2 required 4. Primary Productivity – net gain in organic matter results when the rate of photosynthesis is greater than the rate of respiration

19. Cellular Respiration

20. II. Living Machinery Organic molecules are organized into structural & functional units Molecules  organelles  cells  tissues  organ systems  organism  populations  communities  ecosystems A. Cells & Organelles – the cells is the smallest unit of life, organelles within the cells are specialized for particular tasks

21. II. Living Machinery 1. Prokaryotic cells – Fig. 4.7 Lack a membrane bound nucleus & membrane bound organelles(ex - bacteria), have genetic material; photosynthesis or chemosynthesis takes place on the cell membrane; have a cell wall; some have flagellum for locomotion

22. Prokaryotic Cell

23. II. Living Machinery 2. Eukaryotic cells – Fig. 4.8 Have a membrane bound nucleus and organelles a. Nucleus – control center b. Endoplasmic reticulum (ER) – packages organic molecules c. Golgi complex – packages & ships d. Mitochondria – site of cell resp.

24. II. Living Machinery e. Chloroplasts – site of photo. f. Cell wall – protects • Cell membrane – regulates what enters & leaves the cell • B. Levels of Organization – Table 4.1

25. Eukaryotic Cell - Animal

26. Eukaryotic Cell - Plant

27. Challenges of Life in the Sea Organisms have evolved numerous adaptations that allow them to live in a wide variety of habitats – Must maintain homeostasis - planktonic – drift with currents - benthic – live at the bottom of ocean - nekton – organisms that can swim

28. Challenges of Life in the Sea planktonic Benthic nekton

29. Challenges of Life in the Sea A. Salinity – avg. 35% - most organisms must maintain lower body salt concentration than ocean • 1. diffusion – movement of molecules down their concentration gradient; no energy required; osmosis – diffusion of water • 2. osmoconformers – organisms that do not actively maintain salt and water balance, their internal concentrations change as salinity of water changes

30. Challenges of Life in the Sea • 3. osmoregulators – control the concentration of their internal environment • 4. hypotonic – a solution that has a lower concentration of solutes that that of a cell placed into it; therefore water moves into the cell causing it to burst isotonic – concentration of solutes and water equal that of the cell, therefore no net movement of water hypertonic – a solution that has a higher solute concentration than that of a cell placed into it, therefore water moves out of the cell

31. Challenges of Life in the Sea

32. Challenges of Life in the Sea

33. Challenges of Life in the Sea 5. Marine fish – have a lower salt concentration than seawater, therefore tend to loose water; adaptations to maintain homeostasis include (Fig. 4.14) • Drinks seawater • Excretes excess salt through gills • Excretes small volumes of concentrated salty urine

34. Challenges of Life in the Sea 5. Fresh water fish – higher salt concentration that fresh water, therefore tend to gain water; adaptations to maintain homeostasis include • Does not drink water • Salt absorbed by gills • Excretes large volumes of dilute urine

35. Challenges of Life in the Sea 6. Adaptations of other marine organisms • Sea turtles/sea gulls/sea lions have glands near the eyes that excrete “salty” tears (Fig. 4-15) • Mangroves/spartina grass – excrete excess salt through leaves Salt crystals on spartina grass

36. Challenges of Life in the Sea • Temperature – most metabolic reactions proceed faster at higher temps. (up to a point) 1. Terms to describe temp. of body a. Poikilothermy – having a body temp. that changes with that of the environment b. Homeothermy – maintenance of a constant high body temp. & metabolic rate 2. Terms to describe where the body heat comes from a. Ectotherm – an animal that must use environmental energy and behavioral adaptations to regulate body temp. b. Endotherm – an animal that uses metabolic energy to maintain a constant body temp.

37. Challenges of Life in the Sea Angel Fish – poikilotherm, exothermic Walrus – homeotherm, endothermic

38. Challenges of Life in the Sea • Surface area to volume ration – determines how rapidly heat and materials flow in & out of organisms (Fig. 4.17) - larger organisms have smaller SA/V than smaller organisms - smaller organisms can rely on diffusion alone - larger organisms must rely on well developed respiratory; circulatory, and digestive systems

39. Challenges of Life in the Sea

40. IV. Perpetuating Life • Modes of reproduction 1. Asexual – offspring are genetically identical to parent a. Binary fission – bacteria and some fungi; division of parent cell into 2 equal daughter cells b. Budding – sea anemone; division of parent cell into 2 unequal daughter cells

41. IV. Perpetuating Life Binary fission in a bacterium Budding in yeast

42. IV. Perpetuating Life 2. sexual – offspring are genetically unique a. Gametes (sex cells) are formed by meiosis (reduction division) b. Fertilization – fusion of gametes to produce a zygote c. Zygote divides to produce embryo

43. IV. Perpetuating Life • Reproductive Strategies 1. external fertilization/external development; fishes & frogs - parents don’t help - large numbers of egg & sperm released - death from disease/predation is high

44. IV. Perpetuating Life 2. internal fertilization/external development; birds/reptiles - sometimes parents raise young - smaller brood sizes than fish/amp. - lower death rate than fish/amp. 3. internal fertilization/internal development; some fish/mammals - parents play very active role in raising young - small litters - higher survival rate

45. IV. Perpetuating Life External fertilization – External Development

46. IV. Perpetuating Life Internal fertilization – External development

47. IV. Perpetuating Life Internal fertilization – Internal development

48. V. Diversity of Life in the Sea • Evolution – theory that all species evolved from a pre-existing species; natural selection is the process by which evolution occurs; traits are selected for or against, this results in some characteristics being passed on to future generations and some are not • Classifying Living Things – phylogeny is the evolutionary history of a species 1. binomial nomenclature – a two named system developed by Linnaeus 2. What do scientists look at when classifying? - comparative anatomy - comparative biochemistry (DNA/RNA) - Embryology - Cytology - Fossil record 3. Taxonomic Levels – See Table 4.2

49. V. Diversity of Life in the Sea Comparative Anatomy Comparative Biochemistry

50. V. Diversity of Life in the Sea Comparing Fossils Comparative Embryology