Introduction To Ecology PDF

Principles of Ecology Introduction to Ecology What is it? Why care?  What is Ecology? For now, think of ecology as describing the relationships between living organisms and their environment.  Why care about ecology? Humans are an integral part of ecological...

Principles of Ecology Introduction to Ecology What is it? Why care?  What is Ecology? For now, think of ecology as describing the relationships between living organisms and their environment.  Why care about ecology? Humans are an integral part of ecological systems and they depend on them for survival and quality of life The human population will soon occupy most of the land surface of the planet Earth and their activities are currently altering the biosphere, making it less capable of sustaining human civilization. Trajectory of the human population Earth at night USA at night  Humans & the Biosphere How many humans are there on the planet today? 7.888 billion in 2021 so 8.3 billion in 2024 What is the “doubling time” of the human population now? With this many humans and the population doubling ~61 years, what’s next? The Blue Planet It’s the only one that we know of and the only one we’ve got. The biosphere is fragile. We depend on it for everything we need and want.  The Blue Planet The biosphere is a complex interacting system, of living organisms and the physical environment Through “ecological processes”, living organisms made the blue planet more hospitable to life. These interactions gave rise to increasing “biodiversity” through geological time.  Humans enter the picture Never before has a single species had such a profound, and adverse, effect on the biosphere, making it less capable of supporting life Mass extinctions are not new. Before they were caused by other catastrophes such as a meteor hitting the planet.  Global Atmospheric Changes Ozone depletion Global warming Caused by human population and their waste products  Global Warming 1875 2004  Homo sapiens as a species The relationship between humans and “nature”: Is there a difference? Are humans “natural”? Are humans subject to the “laws of nature?” = principles of ecology These are questions that we ask you to consider throughout the course.  What is Ecology? First coined by the German zoologist Ernest Heckel in 1866 Derived from Greek word oikos meaning “Home” or place of dwelling Ecology might therefore be thought of as the ‘home life” of living organism  What is Ecology? Ecology is the science that seeks to describe and explain the relationship between living organisms and their environment. Ecologists describe and quantify the connections between an organism and its environment.  Another definition of ecology Ecology is the science that seeks to understand the distribution and abundance of organisms. (emphasis in EVE 101) Ecologists create & test hypotheses that predict patterns in the distribution and abundance of organisms.  In summary ecology is …. The study of living organisms in the natural environment How they interact with one another How the interact with their non-living environment  What do we mean by the environment? The environment of an organism consist of all those factors and phenomena outside the organism that influence it: Biotic factors- all living organisms inhabiting the Earth (other living organisms) Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents)  What do we mean by interactions Simply interactions between organisms and their environment How the different components of the ecosystem interact for survival What is the interaction here? How about here? …and here? And this one? There are many more interactions…. 3 2 Levels of Organization Ecologist study organisms ranging from the various levels of organization: – Individual – Population – Community – Ecosystem – Landscape – Region* – Biosphere  An organism is an individual living thing, such as a crocodile (single species). Organism Organism  A population is a group of the same species that lives in one area. Population Population Organism Organism  Population Population = a group of individuals New individuals are born Individuals of any age can die As a result of births and deaths, the number of individuals changes with time: Population Growth or Behavior = change in the numbers of individuals with time  A community is a group of different species that live together in one area. Community Community Population Population Organism Organism  Community Community = a group of populations of different species occurring in one place; individuals of different species may interact with each other (predator, prey)  An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area. Ecosystem Ecosystem Community Community Population Population Organism Organism  Ecosystem Ecosystem= a group of communities and the populations within them embedded in a common physical environment and tied together by physical processes. Landscape = a group of ecosystems that may or may not interact in a given region  A biome: a group of ecosystems that have the same climate and similar dominant communities. Biomes are usually classified according to the predominant vegetation Biome Ecosystem Ecosystem Community Community Population Population Organism Organism  Levels of ecological organization Biome = a group of landscapes within a common climatic regime Biosphere = a group of biomes and ecosystems embedded in and interacting with the physical environment of a planet