Origin of Life Chapter 2

Transcription

1 Origin of Life Chapter 2

2 Origin of the Universe Big Bang Theory Common scientific theory states that the universe existed as a concentrated single point, containing all known matter and energy. Single point begins to expand about 13.7 billion years ago. Young universe was very hot and took about 1 million yrs. for it to cool so that the first elements could form. Most matter was composed of: Hydrogen and Helium

3 Big Bang Theory Gravity attract H & He atoms together. Matter accumulations become denser as gravity pulled them together. Protostar: warm, dense core caused by matter collapsing and compacting under its own weight. Caused by increasing density. Protostars continue to contract until the core pressure and density get so high that nuclear reactions begin. This reaction creates stars from nuclear fusion. Nuclear fusion: reaction in which light atoms unite to form heavy atoms, releasing tremendous energy in the process.

4 Big Bang Theory Heavy elements form as hydrogen atoms fuse. Star s core becomes denser. Star eventually collapses under extreme gravity forces. Supernova occurs (a large nuclear explosion) Explosion generates heavier atoms.

5 Origin of the Solar System Began with a large cloud of H & He. Known as a nebula. Shockwave of a supernova causes the cloud to condense and then spin. It then flattens into a disk due to its rotation. ti

6 A sun develops at the center of a protostar from nuclear fusion. Some of the gas continued to revolve around the sun condensing into masses too small to become stars. condensing into masses too small to become stars. Formed: Planets

7 Origin of the Earth and Moon Earth and the planets formed through accretion: the process by which small particles clump together because of gravity. The more gravity, the more additional mass it attracts. Density Stratification: process forming the layers of the Earth. Core: contains Fe and Ni Surface: O and Si

8 Orpheus theory: a planet-sized body, possibly another planet about 1/3 the size of Earth, struck Earth during its early development and sent some of its material into orbit, forming the Moon

9 Origin of the Atmosphere and Oceans As the Earth cooled and the surface solidified,,gases released by volcanic activity accumulated in the early atmosphere as water vapor, CO 2, and N. Water vapors formed clouds, then rain but the rain boiled off when it hit the ground. After further cooling, Earth s surface allowed for rain to accumulate forming the oceans. Although oxygen is essential for almost all life, early life didn t use oxygen. Oxygen entered the atmosphere about 1.5billion years ago.

10 Marine Environments Life Zone: region that contains characteristic organisms that interact with one another and with their environment. 6 Major life zone: 1. Intertidal Zone 2. Supratidal Zone 3. Subtidal Zone 4. Pelagic Zone 5. Neritic Zone 6. Oceanic Zone

11 Intertidal Zone Area located between high tide and low tide. At high tide the ocean reaches its highest point along a beach At low tide the ocean is at its lowest level. Strandline: a long line of seaweed and debris deposited on the beach during each high tide.

12 If you were to turn the seaweed over, tiny crustaceans called beach hoppers or beach fleas would dart and jump about. You can also find a variety of marine invertebrates, including other crustaceans, worms, and mollusks. Bloodworms Beach Hoppers Dungeness Crab Razor Clam

13 Supratidal Zone The area above the intertidal tid zone, up to the sand dunes. Good distance from the ocean but you can smell it because of the fine mist of salt spray from the crashing waves. Salt spray limits i the growth of plants in the lower supratidal zone. Many species of grasses, shrubs, and trees grow in the upper supratidal zone due to less salt spray.

14 Includes an area of heavy wave impact, and the sandy area beyond that, which is affected by underwater turbulence. Subtidal Zone Some organisms in this zone have structures that help them cling to hard substrates. Other organisms posses a flattened body. A flat body minimizes exposure to wave impact.

15 Encrusting sponges secrete an acid that enables them to bore into rocks and shells. Sea stars cling to hard surfaces by means of suction from their tube feet.

16 Marine snails and sea anemones cling to hard surfaces using their muscular feet. Barnacles literally cements itself with glue to rocks and other hard substances. Mussels cling to rocks by secreting tough, fibrous byssal threads that stick to hard substances.

17 Kelp and Rockweed are anchored to rocky surfaces by a fibrous pad of tissue called a holdfast.

18 Pelagic Zone Pelagic means of the open ocean. Covers the entire ocean of water above the sea bottom the vast region where large schools of fish and pods of marine mammals swim freely. Includes the neritic zone (fewer than 200 meters in depth) and the oceanic zone (more than 200 meters in depth.)

19 Neritic Zone Region of water that lies above the continental shelf: the relatively shallow part of the seafloor that adjoins the continents. Most of the world s commercial fishing takes place here. Rivers that contain runoff from the land flow here and provide nutrients for plankton. Area is sunlit so algae, phytoplankton, p and marine plants can carry on photosynthesis.

20 Oceanic Zone Extends beyond the neritic zone and includes most of the open ocean. 2 parts: 1. Photic zone meaning light The area most suitable for supporting life. 99% of all sunlight that enters the water is absorbed within this zone.

21 Oceanic Zone 2. Aphotic zone no light Includes communities of fish, worms, squid, and crustaceans. Striped Anglerfish Transparent Deep Sea Squid

22 Ocean Basin Known as the Abyssal Plain Deepest part of the ocean floor. Inhabited by many fish and invertebrates and rarely swim near the surface. Goosefish

23 Benthic Zone Includes the entire ocean floor, from the shallow intertidal zone to the deep ocean basin. Benthos: organisms that inhabit the benthic zone. Benthos living on the ocean basin are adapted to regions of very low temperatures and very high pressure. Brittle Star Orange Finger Sponge

24 Sandy Beach Environment Composed of sand, a loose sediment that is easily shifted and moved about by wind and water. Considered a harsh environment. Zonation: patterns of distinct bands of habitats along a coast, each with its own distinct community.

25 The Upper Beach contains beach plants that includes trees, shrubs, and grasses. The roots of these plants hold onto the sand and prevent its erosion by wind and water. The sand collects in small hills, or dunes. Surf Zone: a region of crashing waves which is white foam as a result of air mixing with water as waves pound on the shore. Surf zone moves with the tide as it advances and retreats on the slope of the beach.

26 Rocky Coast Environment Shores made up of solid rock. Rocks provide a surface on which marine animals can attach themselves. 4 major zones can be observed: 1. Upper Intertidal Zone 2. Mid-Intertidal Zone 3. Lower Intertidal Zone 4. Subtidal Zone

27 Upper Intertidal Zone Known as the wave splash zone. Area above the high-tide mark that gets moisture from the ocean spray of crashing waves. Moist rock provide growth of blue-green bacteria. When the bacteria die, they stain the rocks black. The periwinkle snail and the limpet feed off the algae on these rocks. Periwinkle Snails Limpets

28 Mid-Intertidal Zone At high tide, barnacles are covered by water. They feed on plankton and organic debris. Located below the upper intertidal zone. Occupied largely by barnacles, mussels, and seaweeds. During D low tide, they shut their shells tight to keep them from drying.

29 Lower Intertidal Zone Area dominated by seaweed. Tide pools: habitats formed when the spaces between rocks hold water during low tide. Red seaweed

30 Subtidal Zone Located below the lower intertidal zone. Best way to observe life in this zone is by snorkling. Organisms include: Purple Sea Urchin Sea Star Giant Kelp

31 Estuary Environment Estuary: environment formed at the mouth of a river where freshwater and saltwater mix. Along the shores of an estuary, there are many inland bays and creeks. One of the most productive environments found along any coast. Many were formed at the end of the last Ice Age, about 10,000 to 15,000 years ago, when glaciers melted and sea levels l rose.

32 Oceans invaded low-lying coastal areas, flooding the mouths of rivers and streams. Barrier beaches: long ridges of sand formed by sediment carried in by the ocean. On one side of the barrier beach is the bay, on the other side the open ocean. There are 3 types of natural communities in estuary environments: 1. Salt Marsh Community 2. Mud Flat Community 3. Mangrove Community

33 Salt Marsh Community Also known as wetlands. Marsh grasses are the dominant species in the salt marsh. Few organisms eat cordgrass because it is tough and has a high salt content. High in nutrients Nutrients include phosphates p (used for energy) and nitrates (used for growth). Eaten by plankton Cordgrass

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35 Mud Flat Community Characterized by dark, muddy sand and no marsh grasses. Has a slightly sloping beach touched by gentle waves. Very little aeration causing organic debris to accumulate in the sand. Called the graveyard of the estuary. Foul odor from decaying organisms Rotten egg odor, hydrogen sulfide H 2 S.

36 Organisms include: Decay bacteria Mud snails Sandworms Soft shell clams Razor clams Bloodworms

37 Mangrove Community Also called mangrove swamp. Thick growth of mangrove trees cover some bays and inlets. Dominant species is the red mangrove tree. Natural wildlife sanctuary. Protect shore from erosion.

38 Organisms include: Crown conch Fiddler crab snails Mangrove snapper Raccoon

39 Coral Reef Environment Among the most spectacular of marine environments. Stony formation that is built up from the seafloor by a living organism called the coral polyp. Coral larvae settle on the hard substrate in the sand and develop into coral polyps. Coral animals live in colonies. Each new generation of coral lay down a new foundation of limestone, causing the reef to expand upward. Can grow right up to the ocean surface but cannot grow out of the water.

40 Coral Features: Found in the tropical and subtropical regions of the world, 30 o north and 30 o south latitude. Ocean s water is warm and clear, and plenty of sunlight. These are the conditions needed to promote the growth of symbiotic algae within the coral polyps that builds the reefs. Large reefs include: 1. Great Barrier Reef (2000km long) 2. Caribbean 3. Florida keys 4. Belize

41 Classified into two types: 1. hard corals ex. Elk horn, staghorn, brain 2. soft coral fan, sea rod Fan Staghorn Brain Coral Sea rod Elk horn

42 Reef Inhabitants Typical inhabitants include butterfly fish, barracudas, and parrot fish. Reef provides ideal hiding places for both prey and predators. Coral crevices can provide shelter for prey and can also provide shelter for predators like the moray eel. Some fish depend on camouflage the ability to match or blend in with their natural background, to avoid being detected. Others gain protection against predators by swimming in large groups, or schools,, of their own species.

43 Shrimp Decorator crab Upside down jellyfish Stonefish Ghost pipefish

44 Color contrast: in fish, a pattern of different colors that identifies the species. Disruptive coloration: in fish, patterns that obscure body outline, for protection. (spots, bars, stripes) Territory: a home area with well-defined boundaries. Territoriality: behavior in which an organism defend its home area.

45 Banded butterfly fish Disruptive coloration Trumpetfish Camouflage Queen angelfish Color contrast Damselfish Territory Reef shark Territoriality School of fish Camouflage

46 Is there such thing as a poisonous starfish? Crown of Thorns Sun Star Leather Star