Species Diversity Ch. 4

APES Put your cycles book in the bin. If it doesn’t fit set it on the counter next to the bin. Write name on rubric, put inside cover. Everything away except a writing utensil.

As environmental conditions change, the balance between formation of new species and extinction of existing species determines the earth’s biodiversity.

What is Speciation? Formation of a new species

How does Speciation occur? Biological barriers prevent similar species from producing viable and fertile offspring

Isolating mechanism: Geographic Isolation (pre-zygotic) Separation of of species by a geographical feature such as a river, mountain range, ocean, or desert

Harris Antelope Squirrel and Tassel Eared Squirrel in the Grand Canyon

Isolating mechanism: Reproductive Isolation (post-zygotic) Interbreeding occurred Result: Unhealthy and Sterile if born at all

Can a zebra and a horse reproduce? Horse has 64 chromosomes Zebra has 32/46 chromosomes depending on the species

Zorse: Infertile organism with 54 chromosomes

What is Extinction? Species cease to exist Passenger pigeon Great auk Dodo Dusky seaside sparrow Aepyornis (Madagascar)

How Does Extinction Occur? Background extinction = species disappearing at a low rate Mass extinction = Major groups of species wiped out over a short period of time

Endemic Organisms are Most Vulnerable 4 – 6 lbs, 25% smaller than on mainland

How do Speciation & Extinction Affect Biodiversity? Speciation – Extinction = Biodiversity Humans major force in premature extinction

Species Diversity Species Richness - # of total individuals present Species Evenness – number of different types of species Species Dominance – Most abundant species present

Describe these communities in terms of species diversity A  Richness = B  Richness = Evenness = Evenness = Dominance = Dominance = Less Diversity Greater Diversity   25 25 5 5 Circle/HIGH Equal

How to Calculate Species Diversity Uncertainty = Diversity See notes on lab sheet Measures Certainty Diversity = Dominance = Uncertainty

Each Species Plays a Specific Role Called its Niche Total way of life or role of a species in an ecosystem. Includes: - Physical - Chemical - Biological Factors that a species needs to live & reproduce.

Ecological Niches Niche – species way of life or functional role in an ecosystem (occupation) Habitat – physical location in an ecosystem (address)

No Two Species Can Share the EXACT SAME Niche

Fundamental Niche Full potential range of physical, chemical, and biological conditions and resources a species could theoretically use

Realized Niche Range of abiotic and biotic conditions under which a species actually lives

Paramecium Experiment

Overlapping Niches

Competitive Exclusion Principle Two species needing the same resource CANNOT coexist due to limited resources Niches of two species CANNOT overlap completely or indefinitely

Resource Partitioning Dividing up of resource so that species with similar needs use them 1) at different times 2) different ways 3) in different places Fundamental vs. realized niche Hawks vs owls Lions vs leopards warblers

© 2004 Brooks/Cole – Thomson Learning Resource Partitioning Number of individuals Species 1 Species 2 Region of niche overlap Resource use Niche Specialization Number of individuals Species 1 Species 2 Resource use

Broad Classification of Species Generalist Can live in a variety of habitats and/or feed on a variety of species Specialists Specialized to live in specific habitats or feed on specific groups of species

Niche separation Niche breadth Specialist species with a narrow niche Generalist species with a broad niche Niche separation Number of individuals Figure 4.13: Specialist species such as the giant panda have a narrow niche (left) and generalist species such as the raccoon have a broad niche (right). Niche breadth Region of niche overlap Resource use Fig. 4-13, p. 95

Classifying Niches Further Types Definition Examples Native Non-Native Indicator Keystone Foundation

Species Roles Types Definition Examples Native Normally live & thrive in particular ecosystem Non-Native Indicator Keystone Foundation

Species Roles Types Definition Examples Native Normally live & thrive in particular ecosystem Non-Native Exotic, invasive, alien, introduced, migrating African bees, kudzu Indicator Keystone Foundation

Species Roles Types Definition Examples Native Normally live & thrive in particular ecosystem Non-Native Exotic, invasive, alien, introduced, migrating African bees, kudzu Indicator Species whose population/status serves as a measure of ecosystem health Birds, fish, amphibians, trout, canaries Keystone Foundation

Indicators of things like Habitat loss Drought Pollution UV radiation Parasitism Over-hunting Diseases Immigration or introduction of predators or competitors

Species Roles Types Definition Examples Native Normally live & thrive in particular ecosystem Non-Native Exotic, invasive, alien, introduced, migrating African bees, kudzu Indicator Species whose population/status serves as a measure of ecosystem health Birds, fish, amphibians, trout, canaries Keystone Species whose removal would effect many others as they play a critical role Bees, lions, decomposers, sea otters Foundation

Sea Otters

Species Roles Types Definition Examples Native Normally live & thrive in particular ecosystem Non-Native Exotic, invasive, alien, introduced, migrating African bees, kudzu Indicator Species whose population/status serves as a measure of ecosystem health Birds, fish, amphibians, trout, canaries Keystone Species whose removal would effect many others as they play a critical role Bees, lions, decomposers, sea otters Foundation Play a major role Beavers

Beavers