Biology-Chapter 6 Section 2 Vocab (Quizs)

Species

a group of organisms that can reproduce with one another

• Different breeds like Labrador Retrievers or German Shepherds are examples of the same species (Canis lupus familiaris) because they can breed and produce puppies together.

• All organisms that belong to the same kingdom are considered a species.

• Species are defined solely by their physical characteristics and not their ability to reproduce.

• A species is a group of organisms that can only reproduce with members of different species.

Convergent Evolution

When different species develop similar traits because they live in the same kind of environment.

• A penguin and a seal both have flippers to help them swim in the ocean.

• A lion and a tiger both have stripes for camouflage in the jungle.

• A bat and a bird both have feathers for flight.

• A whale and a shark both have fins for swimming.

Gradualism

When species slowly change over a long time through small steps.

• Over many years, some fish in a lake slowly grow longer fins to swim faster.

• Species change rapidly in response to environmental pressures.

• All species remain unchanged over time.

• Species evolve only through sudden and drastic changes.

Allopatric Speciation

Occurs when a species splits into two new species because they are separated by a physical barrier.

• A mountain range separates a group of rabbits into two groups, leading to the formation of two new species.

• Two groups of birds evolve differently due to varying food sources in the same area.

• A river divides a population of fish, causing them to adapt to different water conditions.

• A group of lizards changes color to blend in with their environment, but remains a single species.

Adaptive Radiation (Divergent Evolution)

When one species spreads out into different places and changes to survive in new environments, creating many new species.

• A group of squirrels moves to different parts of a forest, and each group changes to fit its new home. Some squirrels become better at climbing trees, while others become better at digging for food, creating new types of squirrels.

• A single species of fish remains in one lake and adapts to the same environment over time, resulting in minor changes.

• A population of birds migrates to a new island and all individuals develop the same traits to survive in the new environment.

• A group of rabbits stays in a meadow and evolves to have longer ears to hear predators better.

Punctuated Equilibrium

When species stay the same for a long time but then change quickly in short bursts.

• A type of tree that changes slowly over time without any sudden changes.

• A type of tree that stays the same for a long time, but then a fire burns through the forest, and the tree changes quickly to survive. After that, it stays the same for many years again.

• A type of tree that constantly changes its form and structure throughout its life.

• A type of tree that only changes during the winter season.

Sympatric Isolation

When a species splits into two new species without being separated by a physical barrier.

• Two groups of beetles live in the same field, but one group likes to eat grass, and the other likes to eat flowers. Because they eat different foods, they no longer mate and become two different species.

• Two groups of birds migrate to different areas, leading to a separation that causes them to evolve into distinct species.

• A river divides a population of fish, causing them to adapt to different environments and become separate species.

• Two species of frogs live in the same pond but breed at different times of the year, preventing interbreeding.

Macroevolution

Involves big changes over a very long time that create new species or groups of species.

• Involves small changes that occur quickly within a species.

• Involves big changes over a very long time that create new species or groups of species.

• Involves changes that do not affect the genetic makeup of a species.

• Involves changes that are only observable in fossil records.

Stabilizing Isolation

• Occurs when nature selects for extreme traits in a population.

• Occurs when nature selects against extremes in a population, favoring individuals with average traits.

• Occurs when all individuals in a population are equally fit for survival.

• Occurs when a population is isolated from its environment.

Reproductive Isolation

Involves barriers that prevent different species from successfully mating with each other, even if they live in the same area.

• Two types of birds live in the same forest, but one type sings a song at sunrise and the other sings at sunset. Because they sing at different times, they never mate and stay as separate species.

• Two species of frogs live in the same pond, but one breeds in the spring and the other in the fall, preventing them from mating.

• Two types of flowers bloom at different times of the year, ensuring that they do not cross-pollinate.

• Two species of fish inhabit the same river, but one prefers shallow waters while the other prefers deep waters.