An Introduction to Ecology The Distribution and Adaptations of Organisms

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 Plants, animals, bacteria, fungi, protists Abiotic factors – the nonliving parts of the environment Water, oxygen, light, temperature, etc.

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 Example: Community – A group of organisms of different species that live together in a certain area Example: Ecosystem – All the living and nonliving things in a certain area Example: Biome – a group of ecosystems that have similar climates and communities Example: Biosphere – the entire portion of the planet that supports life

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.

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. Regulators (endotherms) maintain a nearly constant internal environment, despite external conditions (Cold-blooded) 2. Conformers (ectotherms) allow their internal environment to vary (Warm-blooded) - live in environments which remain relatively stable

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

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 - athletes in Torino, moving to Denver Morphological Responses - changing the anatomy (structure) of the body - example: dogs growing thicker fur

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

Biomes Aquatic Terrestrial (Our focus will be on these!) Tundra Taiga Tropical Forest Savanna Chaparral Desert Temperate Grassland Temperate Deciduous Forest Let’s work together to research & fill in Terrestrial Biome Chart!

Tundra Arctic = 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!)

Taiga (Northern Coniferous Forest) 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

Tropical Forest T. Rainforest: cm/yr T. Dry forest 150 – 200 cm/yr 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

Savanna Seasonal rainfall; 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

Chaparral Seasonal ppt.; Rainy winter; Long dry summer ( 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

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?)

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

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 Our biome!