Ecology Unit Part 2: Ecology of Organisms

Ecosystem Components Ecologists separate the environmental factors that influence an organism into two types: –Biotic factors –Abiotic factors

Abiotic Factors Are the nonliving factors, the physical and chemical characteristics of an environment Include soil, temperature, humidity, pH, salinity, oxygen concentration, amount of sunlight, availability of nitrogen, precipitation, and wind

Biotic Factors Include all the living things that affect an organism Such as: predators eating their prey, and a butterfly feeding on pollen from a flower

Abiotic & Biotic Factors The importance of each factor varies from environment (habitat) to environment (habitat) They are not independent Organisms change their environment and are influenced by those changes Abiotic factors are not constant

Organisms in a Changing Environment Each organism is able to survive within a limited range of environmental conditions One way to study this is to make a graph of performance versus the values of an environmental variable, such as temperature This graph is called a tolerance curve

Acclimation Is the process through which some organism can adjust their tolerance to abiotic factors This process occurs within the lifetime of an individual organism It is different from adaptation

Control of Internal Conditions Environments fluctuate in their abiotic factors There are two ways for organism to deal with some of these changes –Conformers: are organisms that do not regulate their internal conditions, they change with their environments –Regulators: are organisms that use energy to control some of their internal conditions

Examples of Conformers & Regulators Conformers Komodo dragon Gecko African spurred tortoise Anole lizard Chameleon Anaconda Regulators Sperm whale Orangutan Koloa Armadillo Great Horned Owl Human

Escape from Unsuitable Conditions Some species survive unfavorable environmental conditions by temporarily escaping them Desert animals are nocturnal Some organisms enter a state of reduced activity called dormancy Another strategy is migration, which moving away from the unfavorable habitat

The Niche Organisms do not use or occupy all parts of their habitat at once The specific role of an organism within its environment is called its niche Some species have more than one niche in their lifetime

What does a Niche Include? the range of conditions that the species can tolerate the resources its uses the methods by which it obtains resources the number of offspring its time of reproduction and all other interactions with its environment

Generalists vs. Specialists Are species with broad niches Can tolerate a range of conditions Can use a variety of resources Ex. Pigs Are species with narrow niches Have a limited range of conditions that can be tolerated Have specific resource needs Ex. Koala