Speciation Scenarios

​Speciation Scenarios

By Virginia Smith

​Many organisms live in a desert ecosystem, such as foxes, tortoises, mice, and lizards. A large, swift (fast)-moving cheetah migrates into the desert.

Multiple Select

What are the organisms in the ecosystem? (Choose 2)

• cheetah

• desert

• lizard

• migrate

Multiple Choice

What CHANGED in the ecosystem or in the organism? (Choose 1)

• New predator

• New physical characteristic (trait)

• Different weather

• Different food

• Different number of organisms

Multiple Choice

Was the change GOOD, BAD, or NEUTRAL for the organisms?

• good

• bad

• neutral

Multiple Choice

Which organisms will MOST LIKELY survive and reproduce with the new cheetah predator?

• Mice with thick fur

• Lizards that run fast

• Foxes that have long tails

• Tortoises that run slow

A population of trout live in a cold riverbed. Several years of hot, dry weather has affected the insect populations that the trout eat.

Multiple Select

What are the organisms in the ecosystem? (Choose 2)

• river

• trout

• insects

• hot weather

Multiple Choice

What CHANGED in the ecosystem or in the organism? (Choose 1)

• New predator

• New physical characteristic (trait)

• Different weather

• Different food

• Different number of organisms

Multiple Choice

Was the change GOOD, BAD, or NEUTRAL for the organisms?

• good

• bad

• neutral

Multiple Choice

Which trout in the population are MOST LIKELY to survive and pass their genes on to their offspring?

• The fish with beautiful scales

• The fish with traits most adapted to the new environment

• The fastest and biggest fish

• The youngest and healthiest fish

A new trait that helps plants store more water appears in a cactus population. The trait is beneficial to survival and quickly spreads throughout the environment.

Multiple Choice

What are the organisms in the ecosystem? (Choose 1)

• trout

• cheetah

• cactus

• water

Multiple Choice

What CHANGED in the ecosystem or in the organism?  (Choose 1)

• New predator

• New physical characteristic (trait)

• Different weather

• Different food

• Different number of organisms

Multiple Choice

Was the change GOOD, BAD, or NEUTRAL for the organisms?

• good

• bad

• neutral

Multiple Choice

Which is the most likely source of the new trait?

• A mutation in a gene for a water-storing protein

• A combination of recessive genes across multiple generations

• A replication of multiple genes

• The adaptation of new genes to existing genes for photosynthesis

Mosquitos living near beaches almost went extinct. The mosquito population is now increasing. The new mosquitos developed resistance to insecticides that killed the old mosquitos.

Multiple Choice

What are the organisms in the ecosystem? (Choose 1)

• insecticide

• mosquitos

• beach

• dragonflies

Multiple Select

What CHANGED in the ecosystem or in the organism? (Choose 2)

• New predator

• New physical characteristic (trait)

• Different weather

• Different food

• Different number of organisms

Multiple Choice

Was the change GOOD, BAD, or NEUTRAL for the organisms?

• good

• bad

• neutral

Multiple Choice

How did the insecticide resistance MOST LIKELY happen in mosquitos?

• Mutations caused by the insecticides caused the entire population of mosquitos to genetically change at the same time.

• Dragonflies that had developed resistance to insecticides crossbred with mosquitos, transferring resistance to the mosquito population.

• Offspring that were not exposed to insecticides had time to develop resistant traits. Their offspring outcompeted those lacking the traits, changing the population.

• Offspring that benefitted by inheriting several mutations outcompeted the offspring lacking the mutations. So, the population changed.

The pictures show two different trees that lived millions of years apart in a forest. The early tree is extinct, but is drawn based on fossil evidence. Scientific data reveals that the early tree is an ancestor of the modern tree.

Multiple Choice

What are the organisms in the ecosystem? (Choose 1)

• fossils

• trees

• forest

• extinct

Multiple Select

What CHANGED in the ecosystem or in the organism? (Choose 2)

• New predator

• New physical characteristic (trait)

• Different weather

• Different food

• Different number of organisms

Multiple Choice

Was the change GOOD, BAD, or NEUTRAL for the organisms?

• good

• bad

• neutral

Multiple Choice

Which statement best explains why the trees changed over time?

• Humans cut down trees, causing each generation to be smaller in size.

• The changing environment caused unfit trees to die. Better adapted trees were smaller in size.

• As the Sun aged, its energy output decreased and limited the size trees could grow.

• As flowering plants emerged, fewer resources were left for trees.

A fossil of an Archeopteryx was recently discovered. This fossil is of a dinosaur that lived approximately 150 million years ago. The dinosaur lived with birds and reptiles in the forest. It had a long, bony tail, like a reptile. Unlike other reptile fossils, it also had feathers and wings, similar to a bird.

Multiple Select

What are the organisms in the question? (Choose 3)

• reptiles

• cactus

• birds

• archeopteryx

Multiple Choice

What CHANGED in the ecosystem or in the organism? (Choose 1)

• New predator

• New physical characteristic (trait)

• Different weather

• Different food

• Different number of organisms

Multiple Choice

Was the change GOOD, BAD, or NEUTRAL for the organisms?

• good

• bad

• neutral

Multiple Choice

What is the MOST LIKELY reason for the natural selection of both a tail and wings?

• Reproduction between reptiles and birds

• Increased survival rates of the organism

• Sudden increase in earth temperature

• Iron buildup in the blood