organisms and population

botany

what is ecology

study of interaction b/w living organisms and its environment

basic unit of ecology and functional unit of ecology

basic unit= organism

functional unit= ecosystem

levels of biological organisation

macromolecules

cell, tissues, organs, organisms

population

communities

ecosystem

biomes

biosphere

ecology at organism level is 

physiological ecology

how an organism functions to adapted in an environment in survival and reproduction

population ecology benefits

helps to understand genetics and evolution

many forces like natural selection work on population

four main levels of ecology

organism

population

communities

biome

population is group of same

species

population attributes are

birth rate

death rate

sex ratio

population density

birth rate/ death rate formula

change in population/ initial population

population increasing or decreasing can be determined in age pyramid by

pre reproductive individuals more than reproductive then population increasing or lowermost section big

pyramid shape for increasing, stable and decreasing population

triangular

bell shaped

urn shaped

Four ways to measure population density

1. total number

2. biomass cover

3. relative density

4. indirect count

population growth equation

N_t+1 = N_t + [ (B+I) - (D+E) ]

in normal conditions which factor important to control population growth

natality and mortality

in newly colonised area which factor most important

immigration

maximum reproductive fitness measure is

r value

or intrinsic rate of natural increase

maximum number of individuals which ecosystem can support

K carrying capacity

sum total of all factors which limits population size

environmental resistance= K-N/K

N= population size

which growth seen under unlimited resources

Exponential growth

J curve

differential and integral form of exponential curve

growth seen under limited conditions

logistic growth

more realistic

sigmoid curve

most common in nature

eg. bacteria growing in a petri dish

differential and integral form for logistic growth

show all phases of logistic growth

Magnitude of (r)intrinsic rate for Norway rat, flour beetle

0.015

0.12

In ____, r value for human population in india was_____

1981

0.0205

which organisms breed once in lifetime

bamboo

pacific salmon fish

which organism produce many small sized offspring

oysters

pelagic fishes

why do population grow more slowly as they approach carrying capacity

density dependent factors lead to fewer births and increased mortality

interspecific competition is more severe than intraspecific competition

true false

false

intraspecific is more severe

inter or intra specific competition more potent for evolution

interspecific

siberian cranes in bharatpur wetlands

less than 10

darwin observed which growth while developing his theory for natural selection

exponential growth

animals realise fully its innate potential and increase in number even elephants

darwinian fitness is measured by

high ‘r’ value

max reproductive fitness

in which interaction, interacting species live closely

predation parasitism commensalism

herbivores are also predator

true false

true

prickly pear cactus wrcked havoc in _____ in the year_____ and brought in control by_____

australia

1920’s

cactus feeding moth

assertion- predators help in maintaining species diversity

reason- they reduce the intensity of competition among prey animals

true and correct explanation

starfish pisaster a predator is found in

rocky intertidal communities of american pacific coast

what happened when starfish pisaster was removed

more than 10 species of invertebrates became extinct within a year because of interspecific competition

nearly ___ percent of insects are phytophagous (plant sap feeders or other parts)

25 percent

which plant produces highly poisonous cardiac glycosides

Calotropis

chemicals extracted from plants on a commercial scale

nicotine

strychnine

quinine

caffeine

opium

competitive exclusion principle was given by

Gauss

competitive release example

connells elegant field experiment

on the rocky sea coasts of scotland larger and superior barnacle balanus dominates and excludes smaller cathamalus. if balanus is removed then cathamalus expands

competitive co existence or resource partitioning given by

mc arthur

competitive co existence or resource partitioning examples

1. coexistence of 14 darwins finches

2. 5 species of warblers

competition can occur b/w two unrelated species and related species also

true

unrelated species like visiting flamingoes and resident fishes compete for zooplankton

1. competition occurs only in limited resources

2. competition occurs in unlimited resources

true false

false

true

herbivores and plants are more affected by competition than plants

true false

true

competition is best defined as a process where

fitness of one species is significantly lower in presence of other species

what is gauss exclusion principle

two closely related species competing for the same resources cannot coexist indefinitely and inferior one will be eliminated eventually

commensalism examples

amensalism examples

J shaped growth curve can be observed for

algal bloom

mosquitos and insects in rainy seasons

adaptations in parasites

host specific

loss of unnecessary sense organs

loss of digestive system

presence of adhesive organs and suckers

high reproductive capacity

complex life cycle

examples of ectoparasite like cuscuta

cuscuta or amarbel is found growing on hedge plants and is devoid of chlorophyll and leaves but has houstorial roots that derive nutrition from xylem and phloem of plant

female mosquito is not considered a parasite why

they don't live on or in a host for an extended period and don't rely on it for their sole survival

1. the anatomical and morphological features of endoparasites are greatly simplified

2. high reproductive potential

3. complex life cycle

true false

true

niche explains

functional role of an organism in its habitat

no two species in same habitat have same niche