Biodiversity and Evolution Chapter 4

Biodiversity: Definition The variety of earth’s species, their genes, the ecosystems, energy and matter cycling It is a renewable resource!

Species’ Origin 1.Biological Evolution: how life changes over time 2.Natural Selection – traits that survive 1.Genetically based traits that enhance survival are passed on 2.Results in a change in a population’s genetic characteristics 3.Six kingdoms of life: eubacteria, archaebacteria, protists, plants, fungi, animals

Kingdoms

Species’ Origin 3. Evidence is in fossil records 4. Populations, not individuals, evolve a.Mutations: random changes in DNA structure/number b.Mutagens: agents that enhance mutations c.Mutations that take place in gametes are passed on

Species’ Origin 5. Beneficial Traits a.Adaptation: heritable trait that enables survival & reproduction b.Differential Reproduction: leave more offspring (ex. – thick coats in wolves) c.Genetic Resistance: ability of 1 or more organisms in a population to tolerate chemicals designed to kill it (ex. Antibiotic resistant bacteria)

Climate and Geologic Effects 1.Geological Processes a.Plate Tectonics: continent location determines climate allowed for species to move and adapt →→→ new species b.Earthquakes: can separate and isolate species c.Volcanoes: disrupt/destroy habitat

Climate and Geologic Effects 2. Climate & Catastrophes a.Ice Ages, warm periods change things b.Ecosystems change with climate c.Asteroid Collisions! Duck!

Speciation, Extinction, Human Activities 1.Speciation: a new species evolves; Occurs in 2 “phases”: a.Geographic Isolation (migration, geographic barriers, wind) b.Reproductive Isolation: mutation & change by natural selection c.These are mutually exclusive

Speciation, Extinction, Human Activities 2. Human Role: artificial selection and genetic engineering 3. Extinction: a.Endemic Species: found in one area only; very vulnerable b.Example of recent extinction: Golden Toad 4. Background Extinction: low rate; 1-5 species/million

Speciation, Extinction, Human Activities 5. Mass Extinctions: large groups, wide-spread a.Makes way for new species to emerge

Species Diversity 1.Definition: Number of different species in an ecosystem (richness) and relative abundance of individuals in a species (evenness) 2.Examples: a. Rain forest: rich but low evenness b. Aspen forest: low richness, high evenness 3. Geographic location determines richness; rich near equator, decreases to north/south

Species Diversity 4. Rich Ecosystems are productive and sustainable a.Supported by research b.Greater variety of producers = ↑ biomass c.Greater variety/food web = stable

The Roles of Species 1.Each species has a distinct role to play in its own ecosystem Ecological Niche 2.Role = Ecological Niche; a way of life a. Includes all things that affect survival: water, sunlight, space, temperature 3. Generalist Species have broad niches; can live in a variety of places, eat a variety of foods, are tolerant of extreme conditions a. cockroaches, mice, deer, humans

The Roles of Species 4. Specialist Species have narrow niches; can live in one type of habitat, few types of foods, etc. a.Ex. – tiger salamander, panda 5. Native Species: normally live in a specific ecosystem 6. Non-native species: introduced to or migrate to a different ecosystem (killer bees of Brazil) 7. Indicator Species: provide early warnings of ecological damage frogs, trout, birds, butterflies)

The Roles of Species 8. Keystone Species have a large effect on types and abundances of other species a.Vulnerable (few numbers) b.Include pollinators and top predators 9. Foundation Species create and/or enhance habitats for certain other species a.Ex. – elephants, clear trees; promotes grassland b.Ex. - beavers