2. Hox Genes
Think of them as switches or tool boxes for running other genes.
Effect timing and expression of other genes.
Vertebrates have 4 sets of HOX genes, so more options exist in the vertebrates “tool box”

3. Chapter 52 An Introduction to Ecology and the Biosphere

4. Ecology
The study of the interactions between organisms and their environment.

5. Ecology
Integrates all areas of biological research and informs environmental decision making.

6. Organisms
All living things.
Studied at many levels.

7. Ecology - levels
1. Organismal Ecology 2. Population Ecology 3. Community Ecology 4. Ecosystem Ecology 5. Landscape Ecology 6. Global Ecology See page 1145 for definitions and examples

8. Distribution of Species
Limited by interactions between organisms and the environment.

9. Environment Abiotic Factors: non-living factors.
Ex: Temperature, Light, Water Nutrients
Biotic Factors: effect of other organisms.
Ex: Competition, Predation

10. Abiotic Factors
1. Temperature 2. Water 3. Salinity 4. Sunlight 5. Rocks and soil 6. Wind 7. Disturbance

11. Temperature Effects biological processes. Ex:
Cold – cells will rupture if they expand while freezing.
Hot – many proteins denature above 45 oC.
Point – life can only exist over a fairly narrow temperature range.

12. Water Review the properties of water from Chapter 3.
Cells must maintain a correct water potential (keep from exploding or drying out).

13. Salinity
Salt concentration affects osmotic potential and water balance.
Most aquatic organisms are limited by their ability to osmoregulate.

14. Sunlight Provides energy for Ps, which drives most food webs.
Plants often compete for light because of shading or absorption of light by deep columns of water.

15. Rocks and Soil
Physical structure, pH, mineral composition of rocks and soil limit where plants can grow Ex. Se soils.
Plants limit what animals can be found in an area.

16. Wind Effects temperature and water conditions for many organisms.
May carry abrasive particles that limit plant growth by killing the growth points.

17. Disturbance Disturbance is often an important part of an environment.
Allows organisms to re-colonize an area.
Ex: Fire Humans Wind

18. Climate
Shapes environments and what organisms can live in a particular area.
Temperature, precipitation, sunlight and wind.

19. Global Climate Patterns
Determined largely by solar energy and the movement of heat across the planet.

20. Great Ocean Currents

21. Wind Patterns

22. Climatic Factors Solar Radiation and Latitude Axis Tilt/Seasons
Air/Water Circulation Patterns

23. Solar Radiation and Latitude
Changes the amount of light and energy delivered per surface area.

25. Result Poles: less light Equator: more light
The unequal heating causes air and water to circulate.

26. Seasons Caused by the Earth's tilt. Day length changes over time.
Many organisms are restricted in range by how well they adapt to changing seasons.

28. Global Air Patterns Air rises when heated, sinks when cools.
Zones of rising/sinking are created.
Earth's rotation causes zones to "twist”.

30. Result Air circulation patterns. Rainfall patterns.
rising air: wet areas
descending air: dry areas

31. Biomes
Broad geographical regions with characteristic communities of organisms.

32. Aquatic Biomes

33. Fresh water Biomes Have <1% salt concentration.
Strongly influenced by temperature and light.
Classification – based on water flow patterns.

34. Freshwater Biomes Lakes Wetlands Streams and Rivers Estuaries
See Pg for details

35. Marine Biomes Cover 3/4 of the Earth's surface. Average 3% salt.
Controlled by light and the distance to the shore.

36. Marine Biomes
1. Intertidal 2. Oceanic Pelagic 3. Coral Reefs 4. Benthos See page

38. Light Zones
Photic - Enough light for Ps. Red light lost rapidly as depth increases.
Aphotic - Lacks enough light for Ps and depends on food made in photic zone for energy. Part of the most extensive biome on the planet.

39. Estuaries Where a freshwater river meets the ocean. Salinity variable.
Very productive Biome.

40. Coral Reef Characterized by coral. Found in shallow warm waters.
Very productive.
High species diversity.

41. Benthos
Bottom area.
Usually fed by nutrients drifting down from upper levels.
Fairly rich in life.

42. Biomes Controlled by:
Temperature
Water
Geography

44. Terrestrial Biomes
Recognize all, but be able to describe features of 2-3 types.
See pages

46. Tropical Forests Areas covered with dense growth of trees and vines.
Climate:
Warm temperatures.
Constant day length.
High water.

47. Tropical Forests

48. Tropical Forests
Have the greatest diversity of species of any area on Earth.
Soil is usually very infertile. Most of the nutrients are in the plant life.
One of the most endangered Biomes.

49. Savanna Grasslands with a few trees.
Climate with three growing seasons:
Cool and dry
Hot and dry
Warm and wet

51. Savanna Rich in herbivores and predator species.
Only major biome not found on North America.

52. Desert Characterized by plants adapted to dry growing conditions.
Climate:
Dry (<30cm/yr).
May be cold or hot.
Often found in areas of descending air masses.
Low productivity, but still fairly diverse in species.

54. Chaparral Characterized by spiny evergreen shrubs. Climate:
Mild rainy winters
Hot summers
Ex: Southern California

56. Chaparral Maintained by fires.
Plants adapted to periodic fires by seeds or re-growing from the roots.

57. Temperate Grasslands
Grasses and other herbs are the dominant vegetation.
Climate:
Intermediate water
Relatively cold winters

59. Grasslands Very productive for agriculture. (wheat, corn)
Need disturbance (fires) to keep trees out.
Come in several types:
Tall grass
Short grass

60. Temperate Forests Deciduous trees dominate. Climate:
Relatively high rain
Cold winters
Very little natural area left.
Good diversity of species.

62. Taiga or Northern Coniferous Forest
Coniferous trees dominate.
Climate:
Long cold winters
Short wet summers
Long summer daylength

64. Taiga or Northern Coniferous Forest
Relatively low species diversity.
Being logged at an alarming rate.

65. Tundra Grasses and sedges dominate. Climate: Very cold and dry
Low light in winter

66. Tundra Permafrost present. Plants low in height.
Poor species diversity.

67. Assignments Read Chapter 53 or 43 in Hillis Chapter 52 – Fri. 4/25
Chapter 53 – Mon. 4/28
Labs – Transpiration, Aquatic Productivity

68. Altitude and Latitude Mirror each other.
Their Biomes are similar because the environments are similar.
Ex: Alpine = Tundra

69. Summary Know what is involved with the study of “Ecology”.
Know the major factors of planet Earth that shape climate.
Know the major aquatic and terrestrial biomes and the factors that control them.