Ecosystems and Population Change Flashcards
Ecosystem
The biotic community and all abiotic factors
Community
All the living organisms/populations in an area
Population
Group of organisms of the same species
Niche
Organisms proffession/role in the enviornment
Competition
Having different niches reduces competition between species ex) hawks vs. Owls
Biodiversity
The number and variety of organisms in an ecosystem- greater biodiversity means more stability
indicator species
organisms that provide an early warning that an ecosystem is being changed- sensitive to changes in and ecosystem
invasive species
introduced species that occupy niches of natural populations and out compete them- can cause extinction of natural species
biological control
using a natural predictor to control and unwanted species
genetically modified crops
transfer of genes from one organism to another unrelated organism ex) roundup resistance in canola
biotic potential
the maximum number of offspring that could be produced with unlimited resources
environmental resistance
limiting factors on a population, food, shelter, water, predation, etc.- puts brakes on biotic potential
logistic growth
s shaped curve- type of population where the growth rate is influenced by the population size and natural resistance, leading to a sustainable maximum point known as carrying capacity
carrying capacity
the number of organisms a habitat can sustain over the long term “k”
exponential growth
j shaped curve occurs with short lived populations that rapidly deplete their environment- assumed unlimited resources
overshoots
result when carrying capacity is greatly exceeded and the environment deteriorates
density independent limiting factors
will affect a population regardless of it’s size ex) temperature, natural disasters
density dependent limiting factors
increased effect when the population size increases ex) disease, predation, food supply
taxonomy
naming system- first word is genus, second is the species
species
a group of organisms that can interbreed under natural conditions and produce fertile offspring
Monera
single prokaryotic cells, no nucleus or organelles ex) bacteria and blue green algae
protista
mostly single celled, eukaryotic nucleus, usually aquatic
fungi
multicellular, heterotrophic, chitin cell walls
plantae
multicellular, producers, cellulose cell wall
animalia
multicellular, heterotrophs
limiting abiotic factors in terrestrial ecosystems
soil, available water, temperatures, sunlight
changes to terrestrial ecosystems
forestry, forest fires
ecological succession
gradual change of community as it is either developed from bare land or replace by another community
pioneer community
is the first species to appear during succession
climax community
is the final stable community that results at the end of succession
primary succession
the gradual colonization of an area that has not supported an ecosystem before
secondary succession
the colonization of an area that once supported an ecosystem that was destroyed by fire, flood, etc.
littoral zone
shallow enough for rooted aquatic plants
limnetic zone
from edge of emergent plant zone to the center of the lake, but only to depth of effective light penetration ex) plankton
profundal zone
deep dark area beneath the limnetic zone, feed on organic rain of detritis, bacteria, worms, decomposes
benthic zone
the area at the bottom of the lake or pond
eutrophication
aging to become bogs, meadows and then the forest, matter is added to water through erosion, runoff, etc.
eutrophic lakes
shallow, warm, turbid, and low oxygen always
oligotrophic lakes
have few nutrients, so eutrophication is very slow, deep, cold, higher oxygen
mesotrophic lakes
are between eutrophic and oligotrophic
phylogeny
the history of the evolution of a group of organisms
Lamarck theories
the law of use and disuse: organisms can change their body features during their lifetimes to satisfy their needs.
acquired characteristics are inherited: those characteristics changed during their lifetime can be passed on to offspring ex) giraffes are able to stretch their necks to reach food.
Darwin theories
assumed that all species evolved from a common ancestor from the mainland
proposed that evolution occurred by natural selection and published his theory in 1859
theory of natural selection 5
- overproduction- more produced than can survive
- struggle for existence- competition within and between species
- variation- genetic differences in populations passed on to the next gen
- survival of the fittest- surviving organisms better equipped to compete and reproduce
- speciation- new species arise by accumulation of inherited variations of traits- mutation or new combos
adaptation types
- structural- structures that improve a species ability to survive/reproduce ex) camo
- physiological- based on chemicals ex) pheromones
- behavioral- behaviors ex) migration, hibernation, phototropism
convergence
very different species develop similar adaptations due to similar environments
divergence/adaptive radiation
similar species become quite different due to differing environments
two versions of evolution
1) gradualism- species gain small changes with time
2) punctuated equilibrium- new species exist suddenly with better adaptation- rapidly adaption becomes only one in the environment
evidence for evolution
fossil record
radiocarbon dating
embryology- all embryos go through similar stages
homologous structures- have common origins in the embryos
analogous structures- similar structures but develop from different embryological structures, no common ancestor
vestigial structures- present in organisms that have no present day functions
comparative biochemistry
