Ch 4 Flashcards
Tolerance
Ability to survive and reproduce under range of environmental conditions
When condition goes beyond optimum range…
Organism has to expend more energy to maintain homeostasis, leaving less energy for growth and reproduction
Habitat
General place where an organism lives
Niche
Describes how organism interacts with biotic and abiotic factors
What an organism does
Range of physical and biological conditions in which species lives and the way it obtains what it needs to survive and reproduce
Resource
Any necessity of life
Abiotic factors
Physical aspects
Biotic factors
Biological aspects
Example: when and how it reproduces, food it eats and how it obtains food
Competition occurs when
Organisms attempt to use same limited ecological resource in same place and time
Intraspecific competition
Competition among members of same species
Interspecific competition
Between members of different species
Competitive exclusion principle
No 2 species can occupy exact same niche in exact same habitat and time
By causing species to divide resources competition helps determine…
Number and kinds of species and the niches they occupy
Keystone species
Species that other species rely on in an ecosystem such that if it were removed the ecosystem would change dramatically
Symbiosis
Any relationship where 2 species live closely together
3 types of symbiosis
Mutualism
Parasitism
Commensalism
Mutualism
Both benefit
Parasitism
One organism lives on or in another and harms it
Commensalism
One benefits and other is neither helped nor harmed
Ecological succession
Series of more or less predictable hanged that occur in a community over time
Organisms occupy different places because
Each species has a range of conditions under which it can grow and reproduce
Ecosystems change…
Over time esp after disturbances as some species die out and new species move in
Over course of succession…
Number of different species present typically increases
Primary succession
Succession that begins in an area with no remnants of an older community
Secondary succession
Occurs when disturbance affects a community without completely destroying it
Succession doesn’t always…
Follow same path
Climax communities not always uniform and stable
Secondary selection in healthy ecosystems following natural disturbances…
Often reproduces original climax community
Human caused disturbances
Ecosystems may or may not recover from extensive human caused disturbances
Biomes
Described in terms of abiotic and biotic factors
Examples of abiotic factors
Climate and soil type
Examples of biotic factors
Plant and animal life
Terrestrial biomes
Tropical rain forest Tropical dry forest Tropical grassland/savannah/shrubland Desert Temperate grassland Temperate woodland and shrubland Temperate forest Northwestern coniferous forest Boreal forest/ taiga Tundra
Organisms within each biome can be characterized by
Adaptations that enable them to live and reproduce successfully
Mountain ranges and polar ice caps
Not classified as biomes because they are not easily defined in terms of a typical community of plants and animals
Aquatic organisms are affected primarily by
Waters depth, temperature, flow. And amount of dissolved nutrients
Distance from shore can
Shape marine communities
Water depth influences aquatic life because
Sunlight penetrated only a short distance through water
Photic zone
Sunlight region near surface where photosynthesis can occur
Aphotic zone
Below photic zone where photosynthesis cannot occur
Benthos
Aquatic organisms that live in or on rocks and sediments on bottom of lakes, streams, and oceans
Habitat- benthic zone
Currents can dramatically affect
Water temperature
Freshwater ecosystems can be divided into
3 main categories:
Rivers and streams
Lakes and ponds
Freshwater wetlands
Wetland
Ecosystem where water either covers soil or is present at or near surface for at least part of year
Freshwater bodies
Stream Lake Bog Marsh Swamp
Estuary
Special kind of wetland formed where river meets sea
Estuaries serve as
Spawning and nursing grinds for many ecologically and commercially important fish and crabfish species
Estuary bodies
Salt marsh
Mangrove swamp
Ecologists typically dives oceans into
Zones based on depth and distance from shore
Marine ecosystem zones
Intertidal zone
coastal ocean
Open ocean
