Announcements September 1, 2006 No class on Monday! Have a great weekend. Turn in your ecological...
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Transcript of Announcements September 1, 2006 No class on Monday! Have a great weekend. Turn in your ecological...
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?