By Robyn, Gio and Sarah
Community Structure and Species Diversity
mutualism: interaction between two species in which both species benefit
keystone species: play important roles sustaining their communities
physical appearances: relative sizes, specifications and distribution of populations and species
species diversity/richness: combination of its number of different species
species evenness: abundance of individuals within each species
niche structure: number of ecological niches, how they resemble or differ each other, and how they interact
latitude: distance from the equator
species equilibrium model:
theory of island biogeography:
native species: those that normally live and thrive in a particular community
nonnative/invasive/alien species: species that evolved somewhere else and where later introduced to a community
indicator species: species that serve as early warnings of damage or danger to a community
pollination: flowering plant species by other species
top predator: help regulate the population of other species
- The number of species in an environment is determined by a number of biological factors that determine the capacity of the ecosystem
- Species all play different roles in their ecosystem that make up a balanced and stable environment
- Species interact with one another in a number of ways, as they have different roles that provide an essential part to their ecosystem
- As environmental conditions change, the species communities changes as well, since all the factors affect the species directly
Parasitism: when one species, a parasite, benefits from feeding off or living in an organism (host), that is usually harmed
Mutualism: two species interact in a way that benefits both
pollination mutualism: an association between a plant and a pollinator where each partner benefits from the other(insects, birds, and bats)
nutritional mutualism: both species benefit
Ex: Many fungi are lichenized, each one needs a particular species of algae,
Fungi get photosynthate from algae,
algae get minerals and some desiccation protection and dispersal from fungi
Obligate mutualism- A type of mutualism in which the species involved are in close proximity and interdependent with one another in a way that one cannot survive without the other.
Mutualism Combination: when the relationship between two organisms is a combination of two types of mutualism. birds on the back of African buffalo, clownfish and sea anemone= a combination of nutritional and obligate mutualism
Gut inhabitant mutualism: vast armies of bacteria in the digestive systems of animals help to break down food
ex- bacteria in your body helps you break down food
Commensalism: an relationship between two organisms in which one benefits and the other derives neither benefit nor harm
Ecological Succession: Communities In Transition
Ecological Succession: the process by which the structure of a biological community evolves over time (community starts with pioneer plants and eventually develops to include complex organisms
Primary Succession: process by which a community arises in a virtually lifeless area with no soil
Secondary Succession: succession following a disturbance that destroys a community without destroying the soil
Pioneer Species: first species to populate an area during primary succession
Early Successional Plant Species: often have an open understory with scattered plants that create an umbrella-like canopy. The widely spaced stems allow easy mobility, while the tops of the plants interlace to provide shade and overhead concealment.
Mid successional Plant Species: semi-tolerant of shade, usually fast-growing and longer-lived. As they grow, they also will change the forest environment, making it suitable for shade-tolerant, climax plants. Examples: These include red maple, black and yellow birch, white pine, white and red oaks, and hickories.
Late Successional Plant Species: Shade-tolerant plants/trees. examples: fir, spruce, hemlock, beech, sugar maple and yellow birch trees.
Faciliation: one species makes existence possible for another species
examples: grass & grasshoppers
Inhibition: one species makes it impossible or difficult for another species through competition
Tolerance: the ability of an organism to withstand fluctuations in biotic and abiotic environmental factors
Disturbance: an event, caused by physical, chemical, or biological agents, resulting in changes in an ecosystem
Intermediate Disturbance Hypothesis: Intermediate Disturbance Hypothesis the hypothesis that ecosystems experiencing intermediate levels of disturbance are more diverse than those with high or low disturbance levels
Climax Community: a relatively stable long-lasting community reached in a successional series; usually determined by climax and soil type
Balance of Nature:
1. Nature left undisturbed achieve a single condition that persists indefinitely.
2. If disturbed and the disturbing force is removed, nature returns to the permanent state.
3. In this permanent state, there is a "great chain of being" with a place for each creature; false.
Biotic Change: describes an ordered and expected sequence of changes in an ecosystem
Mature Community: Fairly stable, self-sustaining community in an advanced stage of ecological succession; usually has a diverse array of species and ecological niches; captures and uses energy and cycles critical chemicals more efficiently than simpler, immature communities.
Ecological Stability, Complexity, and Sustainability
Constancy: communities tendency to resist niche changes
Resilience: the rate at which an ecosystem returns to its original state after a disturbance
Complexity: the richness of a biological community, including the number of niches, trophic levels, and ecological processes that capture energy, sustain food webs, and recycle materials within this system
Stability: surviving by changing/adapting as the environment changes. 3 aspects of stability includes inertia/persistance, constancy, resilience. Stability= sustainability; a stable ecosystem survives environmental changes by changing itself.
inertia/persistence. ex ability of a system to resist change. grassland has a low resilience to fire
Precautionary principle: When a threat is of serious environmental damage, we should not wait for scientific proof before taking action