Unit2 Ecology Ia Species

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Ecology I: Species, Populations, Communities and Ecosystems

Ecology ISpecies interactions, Populations, Communities and Ecosystems

ECOLOGY Ecology: the scientific study of

relationships between organisms and their environment Includes the study of the ecosystem structure

and function

Ecologist vs. Environmentalist Is an ecologist an environmentalist? No, not necessarily An ecologist is a scientist studying how

ecosystems work and the relationship between organisms and their environment

An environmentalist is an individual interested in the environment (and may or may not be a scientist)

Levels of organization in the living world: large scale to small scale

Biosphere

Ecosystem

Community

Population

Organism

The sum total of living things on Earth and the areas they inhabit

A functional system consisting of a community, its nonliving environment, and the interactions between them

A set of populations of different species living together in a particular area

A group of individuals of a species that live in a particular area

An individual living thing

Levels of organization in the living world Organism: an individual living thing

Classified by ancestry into species 1.75 million named so far Maybe 3-100 million total

Why are we still so unsure of the number of species on Earth?

Some areas remain little explored (hydrothermal vents, rainforest canopies, tropical soils).

Many species are tiny and inconspicuous (microbes, roundworms, protists, fungi…).

Some species are very similar in appearance (many taxa, even trees, birds, whales).

Levels of organization in the living world

Species One or more populations

Species One or more populations whose members

actually or potentially interbreed under natural conditions

Species One or more populations whose members

actually or potentially interbreed under natural conditions and produce fertile offspring.

Organisms: Population: group of individuals of same

species occupying a given area at the same time

Levels of organization in the living world Organisms: Population: Community: a set of populations of

different species occupying a particular place

Levels of organization in the living world Organisms: Population: Community: Ecosystem: community(ies) interacting

with one another and with the physical environment in a particular place

Ecosystems: Include abiotic factors such as climate, water,

minerals and sunlight as well as biotic factors such as organisms

Ecosystems are the fundamental operational unit of ecology

Species: Distribution & Interrelationships

What determines whether a species will occur at any given place and time?

I. It must be able to get there Evolution, Immigration, Introduction

II. It must be able to survive there Biological and Physical Environment

III. It must be able to reproduce there Suitable mates and environment, etc.

I. Getting there

1. Evolution 2. Immigration:

range expansion

I. Getting there 1. Evolution 2. Immigration 3. Introduction

introduced = exotic = alien species versus native and endemic species

Introduction: Exotic Species

•European Starling

II. Surviving there 1. Physical environment 2. Biological environment

II. Surviving there: Habitat An organism’s place or type of place in

which it lives and thrives. Includes food, water, cover, and space

Microhabitat: the part of the habitat the organism is “really” using

Microhabitat: the part of the habitat the organism is the part of the habitat the organism is “really” using“really” using

II. Surviving there: Niche

What the organism does in its habitat Includes all the physical and biological

factors and interactions of the organism

II. Surviving there: Niche Specialists versus Generalists

Plants and animals with narrow tolerance ranges and/or specific dietary constraints, etc. = Specialists

Plants and animals with wide variety of habitats, foods, etc = Generalists

II. Surviving there: Niche Specialists versus Generalists

Which is more prone to extinction?

Wolf Coyote

II. Surviving there: Niche Which is more prone to extinction?

The wolf—a specialist (carnivore)? The coyote—a generalist (omnivore)?

Answer: the wolf

Fundamental versus Realized Niches

Wolf Coyote

Removal of wolfAllowed coyotesTo expand to fill

Fundamental niche

Surviving there: Niche

II. Surviving there: Physical Environment 1. Range of tolerance

The range of variability in a particular physical factor that an organism can withstand

II. Surviving there: Physical Environment

1. Range of tolerance What an organism can tolerate depends

on…Adaptation: (population level) due to

past evolutionAcclimation: (individual level)

Physiological changes within an individual to slowly changing new conditions

II. Surviving there: Physical Environment

2. Limiting Factors All it takes is one single factor to be outside

of the range of tolerance to limit population growth

This factor is called the limiting factor

Limiting Factors and Saguaro distribution:saguaros are limited to the north by freezing temperatures and to the south by competition with other plants

II. Surviving there: Biological Environment

Mutualism: both gain Predation: predator gains, prey loses Parasitism: parasite gains, host loses Competition: both lose Commensalism: one species benefits; the

other is unaffected Biological environment=interrelationships

INTERRELATIONSHIPSDifferent ways to get along, or not get along

Predation + -

Competition - -Parasitism + -

Commensalism + o

Mutualism + +

+ = benefit- = harmed0 = unaffected

INTERRELATIONSHIPSMutualism

Which Type?

Both gain

INTERRELATIONSHIPSCompetition

Which Type?Both the bobcat and coyote lose

INTERRELATIONSHIPSParasitism

Which Type?

The parasite gains, the host loses

INTERRELATIONSHIPSPredationWhich

Predator gains, Prey loses

INTERRELATIONSHIPSCommensalism

Which Type?

Snake gains home, rodent unaffected (hole abandoned long ago)

INTERRELATIONSHIPS: Review

MutualismWhich Type?

Both gain

INTERRELATIONSHIPS: Review

CompetitionWhich Type?

Both lose available

soil moisture

III. Reproduce there

•Must find suitable mate

•Offspring must be able to survive to reproductive age in order to ensure on-going presence of population

Unit2 Ecology Ia Species

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