Biology - Chapter 14: Ecology Flashcards
Ecological community
-all populations in a given area
Ecosystem
-all organisms in an ecological community + abiotic factors interacting within it
Biosphere
-all ecosystems on Earth, their interactions with each other and the litho, geo, hydrosphere
Density dependent factors
- depend on population density
- e.g. disease, resource competition
Density independent factors
- do not depend on population density
- e.g. climate, weather
Niche
- biotic and abiotic resources an organism uses
- Realized niche: where it truly lives
- Fundamental niche: full range of environmental conditions where it could survive
Gause’s Law
- competitive exclusion principle
- Two species cannot occupy the same niche and maintain population levels, one will outcompete the other
- Resources partitioning allows species to coexist
Intraspecific competition
-occurs between members of the same species
Exploitation competition
- indirect competition
- occurs when resources are depleted, affecting other populations
Apparent competition
-occurs when one predator preys on two species
Mutualism
+/+
Coommensalism
+/0
Parasitism
+/-
Trophic level
- organism’s position within a food chain or food web
- only 10% of energy stored in a trophic level is converted to organic tissue
- primary producer < primary consumer < secondary consumer < tertiary consumer < apex predator
Saprophytes
- plants, fungi, microorganisms
- decomposers that consume dead or decaying organic material and work with scavengers in organic recycling
Detritivores
- worms, slugs
- consume detritus, exposing more organic material for decomposers
K-selected species
- humans, large mammals
- type I survivorship curve
- long gestation period
- few large offspring
- long time to mature
- significant parental investment
- high survival to reproductive age
R-selected species
- bacteria, insects, species w/ free swimming larvae
- type III survivorship curve
- abundant
- small offspring
- mature quickly
- no parental investment
- many do not survive to reproductivee age
Type II survivorship curve
- e.g. hydra, some birds & small mammals, lizards
- Survival probability is constant regardless of age
Ecological succession
- Predictable process where an ecological community develops and changes over time
- occurs in a new habitat or after a disturbance
Primary succession
- occurs after a large disturbance in an area that has never supported life before
- begins with pioneer species
- eventually, a climax community results
Secondary succession
-occurs on terrain that has supported life previously, and has had destruction following a disturbance
Order of Organism Colonization
pioneer species -> thin soil -> vascular plants -> larger plants -> animals
Keystone species
-Maintains ecological balance despite low abundance
Aquatic biomes
- Largest of earth’s biome (75% of earth’s surface)
- Photosynthetic algae contribute most of Earth’s atmospheric O2
- Divided into freshwater biomes (3%) and salt water biomes (97%)
Layers of the ocean
1) Euphotic zone: closest to surface, sunlight (littoral zone is the area of the euphotic zone where sunlight penetrates all the way to the ocean floor)
2) Disphotic zone: semi-irradiated (not sufficient for plants), bioluminescent species produce light here
3) Aphotic zone: bottom, no light or photosynthetic species
