Galapagos FInal

How do islands form?

• plate boundaries

• sea level rise

• hotspot activity

• seafloor uplift

Where is the plate moving in the Galapagos? What are the oldest and youngest islands?

It is moving south east. Oldest island are Espanola & San Cristobal , youngest Fernandina and Isabela>Santa Cruz>Santiago

Where are the Galápagos Islands located geographically?

Eastern pacific ocean

What are the major islands of the Galápagos, and how do their habitats differ?

Española, Fernandina, Floreana, Isabela, San Cristobal, Santa Cruz, Santa Fe, and Santiago

Santa Cruz: Has pampa zone, nonexistent miconia (should have one), scalesia, arid and coastal

Isabela: Pampa zone, again should have miconia but run down by farmers, scalesia, arid and coastal

San Cristobal: all zones

Floreana: all zones

Santa Fe: coastal and arid, and scalesia, pampa potentially.

Santiago:

Which Galápagos islands are inhabited?

Isabela, Santa Cruz, Floreana, San Cristobal

How do hotspots contribute to island formation in the Galápagos?

A hotspot is a crack in the crust, usually with multiple offshoots.

How does plate movement explain the orientation of the Galápagos Islands?

The galapagos plate is moving towards the southeast, and so the oldest islands are in the northwest as the plate moves new islands form over the hotspot

What’s the difference between continental and oceanic islands?

Continental islands are when portions of existing continents form new islands through erosion (Madagascar). Oceanic islands form when plates are colliding (convergent zones), and one plate goes under the other, as the ocean is too heavy for it to buckle up. As the plate melts in the mantle, a volcano and island forms on the other plate(?).

How do sea-level rise and tectonic activity shape islands?

What roles do plate boundaries and hot spots play in island formation?

What geological features arise from different types of plate boundaries?

What are the Nazca and Cocos plates, and why are they important?

What is the Galápagos spreading zone?

What types of lava are found in the Galápagos, and how do they differ?

How are lava tubes formed?

What are tuff cones, and how do they form?

How are beaches formed in the Galápagos?

What ocean currents affect the Galápagos Islands?

How does the Humboldt Current influence the islands?

The dry season in the Galapagos islands (June-December) is when colder water dominates, which is the Humboldt current.

• During a La Niña year, the current is even stronger, there is no warm water, less rain, and terrestrial animals suffer

• In a El Niño, the Humboldt current does not strengthen, and warm water sticks around

  • Terrestrial animals benefit, marine animals suffer

  • Rain

What is the role of the Cromwell Current?

To bring nutrients to the Galapagos islands

How does the Panama Current affect Galápagos climate?

The wet season (January-May) is dominated by the Panama current

• Warm water comes, and warm air can hold more water vapor = wet season

What are temperature inversions, and how do they occur in Galápagos?

In the galapagos, there is a continuous mist at high altitudes, which is a temperature inversion at the top of the island

• Santa Cruz, Isabela, San Cristobal and Floreana

• Th hot gets trapped above cold air and

• cold water of humboldt current

What seasonal climate variations exist in the Galápagos?

wet and dry

How do El Niño and La Niña events impact the islands?

La Niña = humboldt current strengthens more, colder water, dry season lasts and no rain; terrestrial animals suffer and marine animals are more productive

El Nino = humboldt current doesnt strength, warm water from Panama current sticks around, and wet season goes longer

• Terrestrial animals benefit, marine life suffers (sea lions and penguins too)

How do ocean currents influence species colonization of the Galápagos?

Animals can get pulled to the Galapagos on a current (fish, sea lions), or on rafts from the mainland

What is a sister-group relationship, and how does it relate to Galápagos species?

Sister group relationship is the next closest lineage of animals; in the galapgos some have mainland sister lineages on south america, mexico, and central america

How does island biogeography explain species colonization and extinction?

The theory is that the closer the island is to the mainland, the more likely it is to be colonized by migrants, and a larger island is a bigger target.

• closer = more likely

• larger = more resources to share

• Fernandina, Santa Cruz, and San Cristobal fit island biogeography theory

How does island size affect extinction probability?

Proportionally fewer species go extinct on larger islands

Why does island age matter in evolution?

More colonists can appear over time, and in terms of evolution, islands that are older have more biodiversity.

What is endemism, and why is it significant in the Galápagos?

What does the Hardy-Weinberg equilibrium model assume?

What microevolutionary processes affect Galápagos populations?

mostly natural selection, but mutations, gene flow, genetic drift and nonrandom mating also play roles

How does natural selection work?

It needs to be heritable variation (mutations) that lead to differential survival and fitness/reproduction

• happens on microevolutionary scale

Grants case study

• variation is present in beaks of medium ground finch

What is the role of nonrandom mating in evolution?

How did Darwin’s observations in Galápagos contribute to the theory of natural selection?

What are the different forms of natural selection (directional, disruptive, stabilizing)?

What is sexual selection, and how does it operate in the Galápagos?

What are kin selection and group selection?

What are the barriers to gene flow that lead to speciation?

What’s the difference between allopatric, sympatric, parapatric, and peripatric speciation?

How does adaptive radiation occur in island environments?

What is the role of hybridization in evolution, especially in Darwin’s finches?

• hybridization can reverse the process of speciation if it is in its early stages

• hybridization occurring between G. fortis and G. conirostris forming Big birds,

What are the dominant and missing animal groups in the Galápagos?

• dominant: reptiles and birds

• missing: land mammals and amphibians

What plant groups are commonly found in the islands?

• mangroves

• cacti

• scalesia

• ferns

• palo santo

How do elevation and rainfall influence island ecosystems?

• dictates what can grow there

• cacti cannot grow in moist environments like in the pampa zone or scalesia

What is the rain shadow effect?

As hot air with water climbs to elevation, it cools and drops some of its moisture as clouds

• in the rainshadow it is dry and warm

• on other side wet and cooler

What are the vegetative zones of high-elevation islands?

pampa>miconia>scalesia>transition>arid>coastal

What is the intermediate disturbance hypothesis?

the idea that there needs to be stress in the environment for biodiversity to occur

• most of the disturbance is between arid and highlands (transition zone) but not always

• coastlines (wave action, sharks)

• low disturbance, competitive exclusion reduces diversity

  • predators important, and limit abudnace of dominant competeitiors

• at intermediate, balance between disruption of competition and mortality = high biodiverstiy

  • competition mot important

• high disturbance, diversity declines as mortality rises

What is ecological succession?

the process of a new barren rock turning into a lush environment

• in the beginning, there is no soil = no plants can grow

• pioneer species (lava cacti, lichen) primary succession

• once soil is made, get outcompeted by more effective species and go missing from island

  • secondary succession

• i.e. once lava cactus in scalesia zone but outcompeted by the scalesia

What is life history ecology?

• how an organism lives its live

• allocation of energy between reproduction and survival

  • i.e. lower amt of seeds produced to survive better

  • more eggs for bird = less survival

  • affected by stress (food availiability and disturbance)

  • r: 1000s of babies vs, K: 1 baby w parental investment

    • chance of survival

What are density-dependent and density-independent factors?

density dependent: relies on other organisms

• inter or intra specific (based on food source)

• competition

density indepedent: things like El niño

How are age structures and life tables used in population studies?

Age structures: how there is differential survival at different life stages

• you can escape predation if you get large enough

• sea lions and hammerheads

How does competition shape ecological communities?

What is competitive exclusion?

• one species is better than another = excluding someone from resource

• can lead to charcater displacement

  • haver different beak sizes to reduce competitive exclusion

What is resource partitioning?

How do food webs function in the Galápagos?

What is optimal foraging theory?

How do species adapt to abiotic factors like temperature and salinity?

What unique impacts do humans have on island ecosystems?

How did historical human activities like whaling and WWII occupation affect the Galápagos?

What invasive species issues exist in the Galápagos?

How have agriculture and habitat destruction altered ecosystems?

What challenges arise from human migration to the islands?

What is 'Hawaiianization' of the Galápagos?

What are the environmental consequences of increased tourism?

How do cruise-based and land-based tourism differ in their impacts?

What are the effects of overfishing, and how has tourism changed local livelihoods?

What conservation strategies are used in the Galápagos?

What is the role of captive breeding and species reintroduction?

How is habitat restoration conducted in the islands?

How does environmental education support conservation?

What has the research of the Grants contributed to Galápagos conservation?

What is the significance of the California Academy of Sciences collections?