Ecology Midterm Study Guide

A biome with distinct layers of vegetation, each adapted to different light and moisture conditions. For example, the rainforest canopy, understory, and forest floor.

The process by which populations evolve over time as individuals with traits better suited to their environment survive and reproduce more successfully.

A similarity in structure between two or more species due to shared ancestry, reflecting a common evolutionary origin.

Remnants of structures or organs that were present and functional in ancestral organisms but have lost their original function in a particular species.

A biome characterized by high rainfall, constant temperatures, and a high diversity of plant and animal life. Often has a multi-layered structure.

A biome characterized by low rainfall, extreme temperatures, and specialized adaptations in plants and animals to conserve water.

A biome characterized by seasonal rainfall, grasses, and a large population of grazing animals.

A biome characterized by Mediterranean climates with hot, dry summers and cool, rainy winters. Dominated by shrubs and adapted to fire.

A biome characterized by cold winters and warm summers, dominated by grasses and forbs. Adapted to fire and drought.

The largest terrestrial biome, characterized by cold, long winters and coniferous trees that are adapted to harsh conditions.

A pattern of rapid evolutionary change followed by long periods of stability, suggesting that new species arise quickly and then remain relatively unchanged.

Evolutionary process where an ancestral species diversifies into many descendant species, often adapted to different environments.

Traits that enhance an organism's survival and reproduction in a specific environment, developed through natural selection.

The process by which new species arise from existing ones, driven by mechanisms like genetic isolation and natural selection.

The idea that evolution occurs through gradual changes over long periods, suggesting a slow transformation of species.

The idea that species change over time, with descendants differing from their ancestors, leading to the formation of new species.

The gradual accumulation of differences between populations over time that can lead to the formation of new species.

Individuals in a population that possess advantageous traits are more likely to survive and reproduce, passing on those traits.

Evolutionary changes that occur in different species that result in similar traits, even though those species are not closely related. It does not provide information about ancestry.

Not all traits are passed down. Natural selection acts on existing variations within populations, not creating new traits.

A group of organisms that includes a common ancestor but not all of its descendants. Think of it as a family tree where some branches are missing.

A group of organisms that does not share a common ancestor for all its members. The members are not related closely enough to have a single ancestor. Imagine two families with no shared history.

The process by which plants use sunlight, water, and carbon dioxide to create energy (sugars) and oxygen. It's essential for life on Earth.

The first stage of photosynthesis, where light energy is absorbed and converted into chemical energy in the form of ATP and NADPH.

The second stage of photosynthesis, where the energy from light reactions is used to fix carbon dioxide into sugars, forming the basis of plant food.

Tiny pores on the surface of leaves that allow for gas exchange, enabling plants to take in carbon dioxide for photosynthesis and release oxygen and water vapor.

Specialized cells that control the opening and closing of stomata, regulating gas exchange and water loss in plants.

The process in plants where Rubisco mistakenly binds oxygen instead of carbon dioxide, leading to a loss of energy and reduced photosynthetic efficiency. Think of a car engine using the wrong fuel.

Defines a species based on physical characteristics, such as size, shape, and color. It assumes individuals within a species share similar morphology, while different species have distinct traits.

Defines a species based on its ecological role in a particular environment, including how it interacts with its environment, consumes energy, and how it coexists with other species.

Describes the formation of a new species when a population is geographically isolated from its parent population, restricting gene flow.

The process of allopatric speciation begins when a physical barrier, such as a mountain range or river, divides a population into two or more isolated groups.

A subset of a population forms a new species without geographic separation. This occurs through mechanisms like disruptive selection, polyploidy, or habitat specialization.

A form of sympatric speciation where individuals specialize in using different resources within the same geographic area.

The smallest group of individuals on a phylogenetic tree that share a common ancestor and form a distinct evolutionary lineage.

Describes the process of natural selection favoring traits that are distinct from the parent population, leading to the divergence of two or more species.

These plants use a different enzyme, PEP carboxylase, to initially capture carbon dioxide and store it as a 4-carbon compound before the Calvin cycle. This adaptation helps them thrive in hot, dry environments where they need to minimize water loss.

In C4 plants, carbon fixation (capturing CO2) and the Calvin cycle occur in different parts of the leaf. The outer cells fix carbon, while the inner cells run the Calvin cycle. This separation minimizes the interaction between oxygen and the enzyme Rubisco, which helps improve efficiency in hot, dry environments.

The Calvin cycle is the process where plants convert carbon dioxide into sugar. In C4 plants, the Calvin cycle takes place in the inner cells of the leaf.

CAM plants, like some succulents and cacti, separate carbon fixation from the Calvin cycle based on time. They capture CO2 at night when their stomata are open and store it as organic acids. During the day, they release this stored CO2 for the Calvin cycle when their stomata are closed. This adaptation helps them survive in very dry conditions.

C4 and CAM plants have developed strategies to capture carbon dioxide and minimize water loss in hot, dry environments. C4 plants use spatial separation, while CAM plants use temporal separation.