INTRODUCTION TO ECOLOGY 1

ECOLOGY DERIVES COMPONENTS FROM EACH OF THE FOUR BIG IDEAS IN BIOLOGY Big Idea 1: The process of evolution drives the diversity and unity of life Big Idea 2: Biological systems utilize free energy and molecular building blocks to grow to reproduce & to maintain dynamic homeostasis Big Idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes Big Idea 4: Biological systems interact, and these systems and their interactions possess complex properties. Big Idea 4 is where most of our study of ecology is found! 2

ECOLOGY DEFINED. 3 Ecology is the study of organisms and their interactions with the environment.

Levels of Organization 4

TYPES OF ECOLOGY Ecologist use observations & experiments to test explanations for distributions and abundance of species. 1.Organismal ecology is the study of physiology and behavior interacting with environmental challenges 2.Population ecology studies the factors impacting the number of individuals of a species in an area 3.Community ecology is the study of how organisms interact with each other and the environment 4.Ecosystem ecology studies the energy flow and chemical cycling in a given area

ABIOTIC AND BIOTIC INTERACTIONS: LAWS OF THERMODYNAMICS 6

ABIOTIC AND BIOTIC INTERACTIONS

IMPORTANCE OF ABIOTIC FACTORS Not every organism can live everywhere on Earth Abiotic factors determine which organisms can survive where: The Coral Reef is an environment teaming with life, but many organisms would find this environment unsuitable due to its abiotic factors (too much water, temperature, availability of light, etc. )

IMPORTANCE OF BIOTIC FACTORS W. J. Fletcher tested the effects of two algae-eating animals, sea urchins and limpets, on seaweed abundance near Sydney, Australia. In areas adjacent to a control site, either the urchins, the limpets, or both were removed. EXPERIMENT Limpet Sea urchin Both limpets and urchins removed Only urchins removed Only limpets removed August 1982rr February 1983 August 1983 February 1984 Control (both urchins and limpets present) Seaweed cover (%) Removing both limpets and urchins or removing only urchins increased seaweed cover dramatically. Almost no seaweed grew in areas where both urchins and limpets were present, or where only limpets were removed. Seaweed cover (%) 100

MACROCLIMATE CONSISTS OF PATTERNS ON THE GLOBAL, REGIONAL, AND LANDSCAPE LEVEL MICROCLIMATE CONSISTS OF VERY FINE PATTERNS, SUCH AS THOSE ENCOUNTERED BY THE COMMUNITY OF ORGANISMS UNDERNEATH A FALLEN LOG 10 Earth’s Climate Varies By Latitude & Season And Is Changing Rapidly

11 Earth’s Climate Varies By Latitude & Season And Is Changing Rapidly Seasonal variations of light and temperature increase steadily toward the poles Seasonality at high latitudes is caused by the tilt of Earth’s axis of rotation and its annual passage around the sun Belts of wet and dry air straddling the equator shift throughout the year with the changing angle of the sun Changing wind patterns affect ocean currents

Global Climate Change Changes in Earth’s climate can profoundly affect the biosphere One way to predict the effects of future global climate change is to study previous change As glaciers retreated 16,000 years ago, tree distribution patterns changed As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct 12 Earth’s Climate Varies By Latitude & Season And Is Changing Rapidly

HOMEOSTASIS Organisms must maintain homeostasis, a steady-state internal environment, despite changes in the external environment. Organisms respond to abiotic factors in 1 of 2 ways: 1. Regulators maintain a nearly constant internal environment, despite external conditions 2. Conformers allow internal environment to vary - This occurs in organisms whose environments remain relatively stable

14 EURASIA AFRICA SOUTH AMERICA INDIA 135 million years ago Present 65 million years ago 225 million years ago 120°80°0° 120° 80° 40° 120° GONDWANALAND 120° LAURASIA PANGAEA ANTARCTICA AUSTRALIA NORTH AMERICA MADA- GASCAR MADA- GASCAR

HISTORICAL BIOGEOGRAPHY

BIOGEOGRAPHY: LEOPARD DISTRIBUTION

Leopards have the largest distribution of any wild cat, occurring widely in eastern and central Africa, although populations have shown a declining trend and are fragmented outside of sub-Saharan Africa. Within sub-Saharan Africa, the species is still numerous and even thriving in marginal habitats where other large cats have disappeared. But populations in North Africa may be extinct

BIOGEOGRAPHY Serves as a starting point to understanding limits on distribution of species Species absent because Yes No Dispersal limits distribution? Behavior limits distribution? Biotic factors (other species) limit distribution? Abiotic factors limit distribution? Yes No Yes No Area inaccessible or insufficient time Habitat selection Predation, parasitism, competition, disease Water Oxygen Salinity pH Soil nutrients, etc. Temperature Light Soil structure Fire Moisture, etc. Chemical factors Physical factors

ECOLOGY: THE BIG PICTURE Biological systems interact, and these systems and their interactions possess complex properties. 2.Abiotic and biotic factors influence populations, communities, ecosystems, and the biosphere. 3.Over time species have adapted, died, or moved to more suitable environments.