AnnouncementsSeptember 1, 2006

No class on Monday! Have a great weekend.

Turn in your ecological footprint for extra credit

http://www.earthday.net/footprint/index.asp

Basics of Ecology and Evolution(part 1)

Lecture Objectives:

2. Understand the scientific definition of Ecology and Evolution

1. Be introduced to the diversity of life on Earth

3. Learn basic concepts of Ecology and Evolution

What is biological diversity?

“the variety and variability among living organisms and the ecological complexes in which

they occur”

U.S. Office of Technology Assessment (1987)

Scales or types of biological diversity:

Genetic diversity - Amount of genetic variation within or among populations of a given species.

Species diversity - The number of species in a given community.

Community level diversity - Variation in species assemblagesbased on variation in habitat within an ecosystem type.

Ecosystem level diversity - Variation in ecosystems across alandscape or region.

Species are groups of interbreeding organisms.

Biological Species Concept (E. Mayr)

What is a species?

Taxonomy: the study of types of organisms and their relationships.

Linnaeus (1707-1778)

originator of modern scientific classification of plants and animals

Classification ranked according to- similarity- common ancestry

Scientific Classification

Kingdom

King Phillip Can Order Fried Green Snails

Phylum

Class

Order

Family

Genus

Species

Aves

Chordata

Animalia

Haliaeetus

leucocephalus

Falconiformes

Accipitridae

The Kingdoms of Life

Plants Animals Fungi

Protists Bacteria Archaebacteria

Organisms are classified into groups based on how they make a living

The Kingdoms of Life

Bacteria Archaebacteria

Organisms are classified into groups based on how they make a living

Prokaryotes: do not have membrane bound nucleus nor other organelles, are unicellular.

The Kingdoms of Life

Plants Animals Fungi

Protists

Organisms are classified into groups based on how they make a living

Eukaryotes: have membrane bound nucleus and other organelles, can be multicellular or unicellular.

How many species are there?

1.4 -1.7 million described

10-100 million estimated

DiversityInsectsPlantsArthropoda MollusksFungi Algae FishFlatwormsRoundwormsEarthworms BirdsJellyfish, CoralsReptilesStarfishSpongesBacteriaAmphibiansMammals

Animal Diversity

34 Animal Phyla

Over 1 million different species of animals have been described

< 5 % of described animals have a backbone

Vetebrates

Invertebrates

Phylum Porifera: The Sponges

Phylum Cnidaria: jellyfish

sea anemones

coral

Hydra

Phylum Ctenophora: The Comb Jellies

Phylum Platyhelminthes:The flatworms

Phylum Nemertea: The Ribbon Worms

Phylum Nemata: the roundworms

Phylum Annelida: The Segmented Worms

Earthworm

Christmas tree worm

Leech

Phylum Onychophora: Velvet worms

Phylum Tardigrada: Water Bears

Phylum Arthropoda: Crustaceans

LobsterCrab

Water fleas

Phylum Arthropoda: Insects

Butterfly

beetle

cockroach

Ants

Phylum Arthropoda: Centipedes and Millipedes

Phylum Arthropoda: Spiders

Phylum Mollusca:

Snail

Clam

Octopus

Phylum Echinodermata:

Starfish

Sea Urchin

Phylum Chordata:

Tunicates

Vertebrates

Plant Diversity

Food webs:

All species in a community are interconnected to varying degrees.

An estimate of interactions among species between only 2trophic levels (10,000 plants and 100 herbivores) in Hawaii

Sheppard et al. 2004 Mol. Ecol.

From Cohen et al. 2003 PNAS

Keystone species: a species that plays anessential role in community stability.

Indicator Species: a species that providesinformation about the quality of an area.(could be rare or a habitat specialist)

Umbrella species: a species that can be usedas a surrogate for the heath/status of theentire community. (tend to need a lot of area)

Do all species matter? Is there redundancy in communities?

Paul Ehrlich made an analogy between species in communities and rivets on the wing of an airplane. Removing a few rivets from an airplane is undoubtedly safe. How many are you willing to remove?

On average, there are only 2 degrees of separation between any two species in a food web.

Many species are in danger of extinction

WHY??

If current trends continue, 1/5 of all current plant and animal species could be gone or on the road to extinction by 2030.

Percentage of threatened or endangered species in the U.S. imperiled by:

Why are species declining?

Disease - 3%

Overexploitation - 17%

Pollution - 24%

Invasive species - 49%

Habitat degradation and loss - 85%

Dave Wilcove et al. 1998 BioScience

Rarity: A species that is either very uncommon throughout its range, or its range is very small.

Endemism:An endemic species occurs no where else. Most common on islands.

Photo: Darren Irwin

Why value diversity?

Motivation can be based on many principles.

Ethical Moral

Aesthetic Monetary

Spiritual Environmental

Anthropocentric

Basic Ecological Concepts

Ecology – the study of the interrelationship between organisms and their environment

Environment – everything that affects an organism it its lifetime

•Organisms interact with their environment

•Survival of each individual depends on getting enough to eat and not being killed

•Survival of the species depends on births being higher than deaths

Environment can be divided into biotic and abiotic factors

Biotic - Living portions of the environment

Predation, parasitism, competition, etc.

Abiotic - Nonliving factors

Rain, soil type, temperature, etc.

All organism have a range of requirements that determines where they can live

The biotic and abiotic factors of any particular place determine where they do live

Often, there are not enough resources for all individuals in the population

All organisms need resources to grow and reproduce

foodwaterplaces to livemates

Many individuals die before reproducing

Some individuals are better at surviving and reproducing than others

What is Evolution?

The process of change in the traits of populations over time.

Process by which species' characteristics change over generations.

Evolution does not occur within an individual.

Evolution does not occur within a generation.

Traits must have genetic basis.

Adaptive evolution occurs primarily through natural selection

Natural Selection is the process that determines which individuals within a species will reproduce and pass their genes to the next generation.

What is Evolution?

Points to Know

1. Be familiar with the system for classifying living things.

2. What is biological diversity.

3. Understand the difference between the biotic and abiotic environment; know examples of each.

4. What types of resources do organisms need to survive and reproduce?