1. An Introduction to Ecology
The Distribution and Adaptations of Organisms

2. Introduction to Ecology
Ecology is the study of organisms and their interactions with their environment.
The environment includes 2 types of factors:
Biotic factors – the living parts of the environment
Abiotic factors – the nonliving parts of the environment

3. The Importance of Abiotic Factors
Not every organism can live everywhere on Earth
Abiotic factors determine which organisms can survive where:
Temperature – effect on body temperature
Water – too much/not enough water
Light – availability for photosynthetic organisms
Wind – amplifies effects of temperature
Rocks/Soil – which organisms can live with/on them, based on pH and mineral composition
Periodic Disturbances – catastrophes, such as tornadoes, fires, tsunamis, etc.

4. Levels of Organization
Ecologists can look at the world in levels of increasing complexity:
Population – A group of organisms of the same species that live together in a certain area
Community –A group of organisms of different species that live together in a certain area
Ecosystem – All the living and nonliving things in a certain area
Biome – a group of ecosystems that have similar climates and communities
Biosphere – the entire portion
of the planet that supports life

5. Homeostasis
Organisms must maintain homeostasis, a steady-state internal environment, despite changes in the external environment
Organisms respond to abiotic factors in one of two ways:
1. Endotherms = maintain a nearly constant internal environment, despite external conditions (Warm-blooded)
- mammals, birds
2. Ectotherms = allow their internal
environment to vary (Cold-blooded)
- live in environments which
remain relatively stable
- invertebrates, reptiles, fish,
amphibians

6. The Principle of Allocation
This principle states:
Each organism has a limited amount of energy that can be spent on obtaining food, escaping from predators, coping with environmental fluctuations (maintaining homeostasis), growth, and reproduction

7. Adapting to Changing Conditions
Organisms can respond to their changing environments using 3 different types of responses:
1. Physiological Responses
- changing the functioning of the body
- acclimation
- Climbing Mt. Everest
2. Morphological Responses
- changing the anatomy (structure) of the body
- example: dogs growing thicker fur

8. Adapting to Changing Conditions
3. Behavioral Responses
- changing behavior to adapt to the change
- moving to a more favorable location
- cooperative behavior (huddling, etc.)

9. Biomes Tundra Taiga Tropical Forest Savanna Chaparral Desert
Terrestrial
Tundra
Taiga
Tropical Forest
Savanna
Chaparral
Desert
Temperate Grassland
Temperate Deciduous
Forest

10. BIOMES

11. Aquatic Biomes
Aquatic biomes – stratified into zones or layers – defined by light, temperature and depth
Lakes
Wetlands
Streams and rivers
Estuaries
Intertidal zones
Oceanic Pelagic Zone
Coral reefs
Marine Benthic Zone

12. Tundra Arctic = 20-60 cm/yr. Alpine (mountains) = may exceed 100 cm
Average winter temp. -30 degrees C
Summer < 10 degrees C
Long winter; short summer
Herbaceous (low) plants, a few DWARF shrubs due to PERMAFROST.
Musk oxen, caribou, reindeer, bears, wolves, various birds
High latitudes or highest elevations (even at equator!)

13. Taiga (Northern Coniferous Forest)
30-70 cm ; some much more
Winters -50 degrees C in winter
Summer 20 degrees C
Long winter; short summer may be hot
Plants: cone-bearing trees, diverse shrubs,herbs
Animals: Birds, moose, bears, Siberian tigers; insects
Northern N. Am. and Eurasia to edge of tundra

14. Tropical Forest T. Rainforest: 200-400 cm/yr
T. Dry forest 150 – 200 cm/yr
25-29 degrees year round (Warm!)
Summer year round
Plants: diverse; 4 or more layers
Animals: diverse: 5-30 million species yet to be discovered!
Equatorial regions

15. Savanna Seasonal rainfall; 30-50 cm/yr with long drought season
Temperature: degrees C (warm!); more variation that Tropical forests
Dry season lasts 8-9 months
Plants: Scattered trees; thorny; small leaves (why?)Grasses; Must be fire & drought tolerant
Animals: Herbivorous mammals; insects; grazers
Equatorial & subequatorial regions

16. Chaparral Seasonal ppt.; Rainy winter; Long dry summer (30-50 cm)
Cool fall, winter, & spring (10-12 degrees C)
Summer can reach degrees C
Plants: shrubs, small trees, grasses; adapted to drought; some have seeds that germinate after fire.
Animals: mammals (browsers) amphibians, reptiles, insects
Mid latitude coasts

17. Desert < 30 cm / yr (arid/dry) Hot deserts > 50 degrees C
Cold deserts (Antarctica) <-30 degrees C
Temps vary seasonally and daily (colder at night)
Plants: Cacti, shrubs w/ deep roots (why?); small leaf surface area (why?)
Animals: lizards, scorpions; birds; insects; many nocturnal animals (why?)

18. Temperate Grassland
Dry winters; wet summers;; cm/yr.; seasonal drought
Cold winters < -10 degrees C; Hot summers 30 degrees C
Plants: Grasses
Animals: Large grazers; burrowing mammals
Plains & prairies around the world

19. Temperate Deciduous Forest
cm/yr
Cold Winters 0 degrees; Hot summers 35 degrees C; 4 distinct seasons
Plants: Trees, shrubs, herbaceous layer; (broadleaved, deciduous plants)
Animals: variety of mammals, birds, insects
Midlatitudes