4a: The Organism in the Environment

a group of organisms of the same species living in the same place at the same time

all of the populations living in the same area at the same time

if one species is removed from a community it can affect the whole community

place where an organism lives

all the biotic factors and all the abiotic factors that interact within an area at one time

living components

non-living components

yes

• distribution of species

• abundance of species

• interactions between species

• interactions between species and their abiotic environment

biologists that study interactions by investigating ecosystems

square frames made of wood or wire used to investigate population size

they are placed on the ground and the organisms within them are recorded

commonly the abundance of plant species

• number of individual specoes

• species richness

• percentage cover

total number of different species is recorded

approximate percentage of the quadrat area in which an individual species is found is recorded

when it is difficult to count individuals

• 2 tape measures

• quadrat

• random number generator

• species key

• use tape measures to lay out a survey area

• use random number generator to create a set of coordinates to place first quadrat

• count number of chosen species within quadrat

• repeat for second quadrat

• estimate population using equation

(total area / area sampled) x total number of species population counted

compare abundance of study species in each survey area

• competition

• predator-prey relationships

• interactions with other organisms within food chain

• light intensity

• mineral availability

• water availability

• pH

• temperature

• salinity

• missing individual organisms when counting in a quadrat

• difficult to identify species

C - study area

O - same species of quadrats

R - repeat for reliability

M1 - number of designated study species

S - size of quadrat, random way of quadrats, day of investigation

range and variety of different species of organisms on earth or within an ecosystem

• species richness

• variation within species

• distribution and population size of species

• lots of different species

• lot of variation

• even distribution

by human activities

• food

• shelter

• maintenance of physical environment

• stability of ecosystems

• reduced dependence

• resilient to environmental impacts

to demonstrate the importance of biodiversity in an ecosystem

• 2 tape measures

• quadrat

• random number generator

• species key

• use tape measures to lay out survey area

• use random number generator to create a set of coordinates for first quadrat

• count number of different species within quadrat

• repeat for 10 quadrats

• repeat for second survey area

• compare number of different species

larger number of different species

doesn’t tell us about distribution or population size

• easy to miss individual organisms

• identifying and distinguishing between species

C - study area

O - same species of quadrats

R - repeat for reliability

M1 - number of designated study species

S - size of quadrat, random way of quadrats, day of investigation

• light intensity

• temperature

• moisture levels

• soil pH and mineral content

• wind intensity and direction

• carbon dioxide levels

• oxygen levels

needed for photosynthesis

affects rate of photosynthesis

water for survival

affects transpiration

required for photosynthesis

aquatic animals need high oxygen concentrations

• availability of food

• new predators

• new pathogens

• competitions

more food = higher chance of surviving and reproducing

unbalances the ecosystem

population may decline as a result of lack of immunity and resistance

if two species compete for resources and one is better adapted, then that species will outcompete the other