An Introduction to Ecology

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 differentspecies 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 • 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: 24-29 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 30-40 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;; 30-100 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 • 70-100 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