18.3 Biodiversity and Species Interactions
3 min read•august 7, 2024
Biodiversity and species interactions are crucial aspects of ecology. They shape ecosystems, influencing stability and resilience. Understanding these concepts helps us grasp how organisms coexist and adapt to their environment.
From measuring biodiversity to exploring symbiotic relationships, this topic dives into the intricate web of life. We'll learn how species richness, evenness, and interactions like and competition affect community dynamics and ecosystem health.
Biodiversity Measures
Defining and Quantifying Biodiversity
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Top images from around the web for Defining and Quantifying Biodiversity
Frontiers | Linking Terrestrial and Aquatic Biodiversity to Ecosystem Function Across Scales ... View original
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Biodiversity | Biology for Majors II View original
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Biodiversity of the Great Barrier Reef—how adequately is it protected? [PeerJ] View original
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- Biodiversity refers to the variety of life on Earth at all levels, from genes to ecosystems, and can be measured in terms of species richness and species evenness
- Species richness is the number of different species represented in an ecological community, landscape, or region
- Higher species richness indicates greater biodiversity (Amazon rainforest)
- Lower species richness indicates lower biodiversity (Arctic tundra)
- Species evenness is the relative abundance of different species in an area, or how close in numbers each species is
- High species evenness occurs when species are present in similar proportions (coral reef)
- Low species evenness occurs when some species are more abundant than others (invaded ecosystem with dominant invasive species)
Ecosystem Stability and Biodiversity
- Ecosystem stability refers to the ability of an ecosystem to maintain its structure and function over time in the face of disturbance
- Biodiversity contributes to ecosystem stability by providing functional redundancy
- If one species is lost, others can fill its ecological role (multiple plant species can provide food for herbivores)
- Diverse ecosystems are more resilient to environmental changes and disturbances (climate change, natural disasters)
- Greater within species allows for adaptation to changing conditions
- Higher species richness provides more options for ecosystem functions to continue if some species are lost
Species Interactions
Symbiotic Relationships
- Symbiosis is a close and long-term interaction between two different species
- is a symbiotic relationship in which both species benefit
- Oxpeckers eat ticks off the backs of rhinos, providing food for the bird and pest control for the mammal
- Flowers provide nectar for pollinators, while pollinators help flowers reproduce by transferring pollen
- is a symbiotic relationship in which one species benefits while the other is unaffected
- Remora fish attach to sharks, gaining transportation and protection without harming the shark
- Epiphytic orchids grow on trees, benefiting from increased sunlight without affecting the tree
- is a symbiotic relationship in which one species (the parasite) benefits while the other (the host) is harmed
- Tapeworms live in the digestive tracts of animals, absorbing nutrients and causing malnutrition
- Mistletoes grow on trees, stealing water and nutrients, potentially stunting tree growth
Community Dynamics
Predation and Its Effects
- Predation is an interaction where one organism (the predator) hunts, kills, and eats another organism (the prey)
- Predation can shape community structure by controlling prey populations
- Wolves help regulate elk populations in Yellowstone, preventing overgrazing of vegetation
- Predators can also indirectly affect other species in the community
- In a trophic cascade, predators reduce herbivore populations, allowing plant populations to increase (sea otters, sea urchins, and kelp forests)
Competition and Resource Partitioning
- Competition occurs when two or more species use the same limited resource, such as food, water, or space
- Interspecific competition occurs between different species and can lead to resource partitioning
- Different species of warblers forage in different parts of the same tree to avoid competition
- Intraspecific competition occurs within a single species and can regulate population size
- Competition for mates, food, or territory can limit population growth
Trophic Levels and Food Webs
- are the positions that organisms occupy in a food chain
- Primary producers (plants) are at the lowest trophic level, followed by primary consumers (herbivores), secondary consumers (carnivores), and tertiary consumers (top predators)
- A food web is a complex network of interconnected food chains in an ecosystem
- Shows how energy and nutrients flow through the ecosystem
- Helps predict how changes in one species' population can affect other species in the community (removal of a top predator can cause a trophic cascade)
Key Terms to Review (21)
Biodiversityism: Biodiversityism refers to the recognition and importance of biodiversity in ecosystems, emphasizing the interconnectedness of various species and their roles in maintaining ecological balance. It highlights that greater biodiversity leads to more resilient ecosystems, capable of adapting to changes and providing essential services like clean air and water, food production, and disease regulation. Understanding biodiversityism is crucial for conservation efforts and sustainable resource management.
Commensalism: Commensalism is a type of symbiotic relationship where one organism benefits while the other is neither helped nor harmed. This interaction plays a crucial role in various ecological systems, influencing population dynamics and community structure. Understanding commensalism helps in appreciating the complexities of organism interactions within ecosystems, as it demonstrates how different species can coexist without directly impacting each other's survival.
Competitive Exclusion Principle: The competitive exclusion principle states that two species competing for the same limited resources cannot coexist at constant population values. This principle highlights the importance of resource availability and competition in shaping community structure and biodiversity. When two species compete for identical resources, one species will eventually outcompete the other, leading to local extinction or resource partitioning.
Deforestation: Deforestation is the large-scale removal of trees and forest cover, often resulting in damage to the quality of the land. This process can significantly affect local ecosystems, disrupt biodiversity, and contribute to climate change through increased carbon emissions. As forests are cleared for agriculture, urban development, or logging, the consequences extend beyond the loss of trees, impacting wildlife habitats and the overall health of our planet.
E.O. Wilson: E.O. Wilson was a prominent American biologist, naturalist, and author known for his work in ecology, evolution, and biodiversity. He is often referred to as the 'father of sociobiology' and has made significant contributions to our understanding of species interactions, particularly in the context of ecosystems and conservation efforts. His advocacy for biodiversity preservation emphasizes the importance of every species in maintaining ecological balance.
Ecosystem diversity: Ecosystem diversity refers to the variety of ecosystems within a certain area, encompassing the different biological communities and their interactions with the physical environment. This concept is important because it highlights how various ecosystems contribute to overall biodiversity and ecological balance. A rich diversity of ecosystems can enhance resilience to environmental changes, provide a range of habitats for species, and support numerous ecological processes essential for life.
Ecosystemism: Ecosystemism is the philosophy that emphasizes the interconnectedness of all living organisms and their environments, highlighting the importance of biodiversity and species interactions within ecological systems. This approach recognizes that ecosystems are complex networks where the survival and well-being of individual species depend on the health of the entire system. By understanding these relationships, ecosystemism advocates for sustainable practices that promote ecological balance and biodiversity.
Endangered species: Endangered species are organisms that are at risk of extinction due to a variety of factors such as habitat loss, pollution, overexploitation, and climate change. Protecting these species is crucial for maintaining biodiversity, as each species plays a unique role in its ecosystem and contributes to the overall health of the environment.
Genetic diversity: Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is crucial for the adaptability and resilience of populations, allowing species to survive in changing environments and resist diseases. High genetic diversity within a population can enhance survival rates and reproduction, which plays an essential role in maintaining ecosystem health and functionality.
Habitat fragmentation: Habitat fragmentation refers to the process by which large, continuous habitats are divided into smaller, isolated patches due to human activities such as urban development, agriculture, and infrastructure projects. This separation can significantly impact biodiversity and species interactions, as organisms may find it difficult to move between habitat patches, leading to reduced genetic diversity and increased vulnerability to extinction.
Keystone Species: A keystone species is a species that has a disproportionately large impact on its environment relative to its abundance. Its presence or absence can significantly affect the structure and diversity of the entire ecosystem, influencing many other organisms and their interactions within the habitat. Keystone species often play crucial roles in maintaining the balance of the community, making them essential for ecological stability.
Mutualism: Mutualism is a type of symbiotic relationship between two different species where both parties benefit from the interaction. This ecological relationship can enhance the survival and reproduction of both organisms involved, often leading to increased biodiversity. Mutualistic interactions are crucial in various ecosystems, influencing community dynamics and the health of biological networks.
Niche differentiation: Niche differentiation is the process through which competing species adjust their resource use or behavior to minimize competition and coexist in the same habitat. This adjustment can manifest in various ways, such as differences in feeding habits, habitat preferences, or reproductive strategies, ultimately allowing multiple species to thrive within overlapping environments.
Nutrient Cycling: Nutrient cycling is the process by which essential nutrients move through the ecosystem, from the environment to living organisms and back again. This dynamic process involves the transfer of nutrients like carbon, nitrogen, and phosphorus through various biotic and abiotic components, ensuring that these vital elements are recycled and made available for continued growth and survival of species. It plays a critical role in maintaining ecosystem health and biodiversity by supporting the interactions between different species and their environments.
Overfishing: Overfishing occurs when fish stocks are depleted due to catching more fish than the population can reproduce. This practice disrupts the balance of marine ecosystems, threatening not only the targeted species but also those that rely on them, ultimately impacting biodiversity and species interactions within the ocean environment.
Parasitism: Parasitism is a type of symbiotic relationship where one organism, the parasite, benefits at the expense of another organism, the host. In this interaction, the parasite derives nutrients and shelter from the host while potentially causing harm, disease, or even death. This relationship is critical in understanding how organisms interact with their environment and each other, influencing ecosystems and health.
Pollination: Pollination is the process by which pollen is transferred from the male anthers of a flower to the female stigma, leading to fertilization and the production of seeds. This critical mechanism not only facilitates reproduction in flowering plants but also plays a significant role in maintaining biodiversity and supporting ecosystems through interactions with various species.
Predation: Predation is the biological interaction where one organism, the predator, hunts and consumes another organism, the prey, for nourishment. This relationship is crucial for regulating populations within ecosystems, influencing the structure of communities, and driving evolutionary adaptations among species.
Rachel Carson: Rachel Carson was an American marine biologist, conservationist, and author known for her groundbreaking work in environmental science, particularly her book 'Silent Spring,' which raised awareness about the dangers of pesticides and their impact on ecosystems. Her work played a crucial role in the modern environmental movement and highlighted the interconnectedness of biodiversity and species interactions.
Species diversity: Species diversity refers to the variety of different species within a specific ecosystem or on the entire planet, encompassing both the number of species and their relative abundance. This concept is crucial for understanding ecological balance and interactions, as it influences ecosystem resilience, productivity, and stability. A higher species diversity often leads to healthier ecosystems, which can adapt more easily to changes and disturbances.
Trophic levels: Trophic levels refer to the hierarchical positions in an ecosystem that categorize organisms based on their primary source of energy. Each level represents a different stage in the flow of energy and nutrients, starting from producers at the base, followed by various levels of consumers. Understanding these levels helps clarify the roles of different organisms in food webs and their impact on biodiversity and ecological balance.