Speciation and Adaptive Radiation Quiz

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Questions and Answers

What factor likely contributed to the ability of large animals to thrive during the explosion period?

Decrease in marine biodiversity

Increase in oxygen levels (correct)

Development of flight in animals

Increase in carbon dioxide levels

Which developmental aspect is crucial for understanding animal segmentation?

HOX genes (correct)

Symbiotic relationships

Glycolysis regulation

Nervous system evolution

What ecological change is identified as a driving factor for predation during the evolutionary timeline?

Reduction in plant diversity

Rise in atmospheric temperatures

Habitat fragmentation

Evolution of eyes (correct)

What was a significant hypothesis about Earth's conditions prior to 650 million years ago?

Snowball Earth theory Signup and view all the answers

Which question addresses the dynamics of biodiversity changes over time?

How do we get new species? Signup and view all the answers

What defines a species?

A group of organisms that can reproduce only within their group. Signup and view all the answers

What is one major cause of mass extinction events?

Catastrophic events such as asteroid impacts. Signup and view all the answers

What is a likely cause of megafauna extinction?

Overhunting by early humans. Signup and view all the answers

What evolutionary process is referred to when new species arise from existing species?

Speciation. Signup and view all the answers

What defines a species in biological terms?

Organisms that can interbreed and produce fertile offspring Signup and view all the answers

What ethical consideration is often discussed regarding de-extinction?

The potential impact on existing ecosystems. Signup and view all the answers

What was a significant event that led to the extinction of many species?

The Cretaceous-Tertiary impact Signup and view all the answers

How much of the DNA in current Eurasian populations is derived from Neanderthals?

1% - 4% Signup and view all the answers

Why had so many species appeared in a region at one time?

Because of key innovations in adaptation. Signup and view all the answers

What factor contributed to the extinction of megafauna?

Human hunting of megaherbivores Signup and view all the answers

What is the significance of the term 'genetic ghosts' in evolutionary studies?

Describes the links between living species and their extinct relatives. Signup and view all the answers

Which of the following processes does NOT typically shape evolutionary trees?

Random mating patterns Signup and view all the answers

What is a common consequence of second-order predation associated with megafauna extinction?

Population overbalance of prey species Signup and view all the answers

During which mass extinction event did the majority of megafauna become extinct?

Pleistocene Signup and view all the answers

Which of the following was NOT a suggested cause of the extinction of megafauna?

Increased competition among predators Signup and view all the answers

What ethical consideration is important regarding the idea of de-extinction?

Potential ecological impacts on existing species Signup and view all the answers

Study Notes

Speciation, Adaptive Radiation, and Extinction

Speciation, adaptive radiation, and extinction are key processes shaping evolutionary trees.
Evolutionary trees illustrate the relationships among species over time.
Questions about species appearance, extinction, and formation are explored.

What is a Species?

The definition of a species is discussed.
Different concepts of species are explored, including biological, morphological, phylogenetic, and evolutionary species concepts.

Allopatric Speciation

Allopatric speciation occurs when populations are separated by a physical barrier, leading to genetic divergence.
Founder effect is a form of allopatric speciation where a small group of individuals establishes a new isolated population.

Sympatric Speciation

Sympatric speciation occurs when populations diverge without geographic isolation.
Assortative mating can lead to genetic divergence in sympatric populations.

Possible Causes of Adaptive Radiations

Key innovations, environmental changes (new habitats), and ecological changes (new opportunities) are possible causes of adaptive radiations.

Ray-finned Fishes

Ray-finned fishes are the most species-rich vertebrate group.
They exhibit a third whole genome duplication.
They use swim bladders for buoyancy.
They show innovations in jaw structure, including protruding upper jaws and pharyngeal jaws.

Examples of Fish Variation

The diversity of fish is shown through various examples.
Fish vary in morphology/shape and habitats.

Kinetic Skull in Fish

Many fish have a "kinetic skull" with multiple moving parts, unlike mammalian skulls, which are mostly fused bone.

Primitive vs. Advanced Jaws

Early fish had primitive jaws that did not protrude.
Later evolution favored advanced jaws that could protrude for better prey capture.

Pharyngeal Jaws

Pharyngeal jaws are a second set contained within the fishes throat.
They are helpful in manipulating and swallowing prey.

Eel Jaws as an Example of Adaptation

Eels have specific jaw structures enabling them to eat prey without hands and crush tough prey.
Diverseness in jaw structure and morphology is related to diverse food sources and habitats.

New Habitats

Animals adapting to new habitats is a key driver for evolution.

Insular Giants and Dwarfs

Animals on islands may evolve into larger (giants) or smaller (dwarfs) forms compared to their mainland counterparts.
A change in resources available or predation pressure can lead to large or small sizes.

Giant Tortoises

Giant tortoise populations face extinction/being hunted.
Lonesome George (tortoise) was the last of its species.

Meiolania Platyceps

Meiolania platyceps (giant horned turtle) dated to Cretaceous.
Fossils found in various Pacific Islands and Australia.
Hunted species from Vanuatu extinct about 3000 years ago.

Komodo Dragons

Komodo dragons are a species of lizards.

Cambrian Explosion

Nearly all major animal phyla appear in Cambrian rocks (545-525 million years ago).
Many weird/wonderful creatures suddenly appear in the fossil record during the Cambrian Explosion.

What Caused the Cambrian Explosion?

Possible causes for the Cambrian explosion include: environmental changes/developmental changes/ecological changes.

Environmental Changes

Increase in oxygen levels, allowing large animals
Snowball Earth hypothesis (Earth iced over before 650 Mya)

Developmental Explanations (HOX genes)

HOX genes regulate the development of segmentation in animals.

Ecological Changes

Evolution of eyes leading to predation
Arms race between predators and prey.

Late Surviving Mammoths

Many megafauna went extinct about 12,000 years ago.
Some megafauna, like mammoths, survived longer in some areas.

Postglacial Flooding of the Bering Land Bridge

The Bering Land Bridge flooded as glaciers melted.
This event led to new migration routes and habitat changes.

De-extinction

De-extinction (reviving extinct species) is a discussion/research topic.
It includes using existing species DNA to create extinct species again.

Genetic Ghosts

Genetic ghosts are the extinct species DNA found in surviving species
Genetic remnants of extinct species present in modern species

Understanding Human Evolution

Research on human evolutionary paths.
Some genetic material from Neanderthals is present in Eurasian populations.

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Description

Test your knowledge on speciation, adaptive radiation, and extinction processes. This quiz covers definitions, concepts like allopatric and sympatric speciation, and the effects of barriers and mating on species divergence. Explore how these factors shape the evolutionary trees of life.