Mind Map Gallery Ecology - Populations NCERT
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Ecology - Populations NCERT
This Mind Map provides a overview of population ecology. Population ecology is the study of the factors influencing the number and distribution of animal and plant populations.The study of population dynamics and growth, sometimes known as demography, has contributed significantly to population ecology and has its deepest historical origins. The Mind Map briefly covers the attributes of population, the factors, processes, and models of population growth, and life history variation. Visit EdrawMind Gallary to learn more!
Edited at 2022-07-06 13:39:12
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POPULATIONS
Population Attributes
Population ecology
Links ecology to pop genetics and evolution
Natural selection
operates at this level
Birth & death rates
per capita rates
offspring/ individual/ year
change in no./ no. of individuals
Sex ratio
Males: Females
Age groups
Age pyramids
Age distribution plotted w/ population
Shapes reflect growth status
Expanding - Triangular
Stable - Bell shape
Declining - Urn shape
Population size
Explains
Status of organisms
Outcome of competition
Impact of predator
Range
<10 Siberian cranes @Bharatpur in a year
Milliions Chlamydomonas in a pond
Population density N (Measure)
Total number
generally most appropriate
Biomass or Percent cover
Banyan tree, 200 Parthenium histophorus
Relative densities
No. of fish caught/ trap
Indirect Estimation
Tiger census in NP
Pug marks & fecal pellets
Population Growth
Factors
Food availability
Predation pressure
Adverse effects
Processes
Natality B
Mortality D
Immigration I
Emigration E
N(t+1) = N(t) +[(B+I)-(D+E)]
Exponential Growth Model
Unlimited resources
Unimpeded growth
No checks
Enormous population
Followed by crash
J shape
Density independent
dN/dt = (b-d)xN = rN
N
lag
log
crash
r value
flour beetle 0.12
norway rat 0.015
1981 Indians 0.0205
2021 Indians 0.0103
N(t) = N(o) e^rt
Aphids, Algal blooms
Logistic Growth Model
Limited resources
Survival of fittest
S shape - sigmoid
Density dependent
N
lag/ establishing
log/ exponential
deacceleration
stabilizing/ asymptote
Verhulst-Pearl Logistic Growth
dN/dt = rN (K-N/K)
K- carrying capacity
(K-N/K) - environmental resistance
Life History Variation
Evolution
to maximise r
Darwinian fitness
most efficient reproductive strategy
in relation to constraints
imp area of research
One-time breeders
Pacific Salmon, Bamboo
Many-time breeders
Aves, Mammals
Many small sized offspring
Oysters, Pelagic fishes
Few large offspring
Birds, Mammals
Population Interactions
Protocooperation ++
can survive separately
Hermit crab(Paguroidea) in empty gastropod shell w/ sea anemone
Predation +-
E transfer conduit
Opuntia (Prickly pear cactus)
invasive
Australia 1920s
Predator-Moth
Biocontrol
Sps diversity
reduce intensity of competition
Pisaster starfish
American Pacific coast
10 sps inv extinct in 1yr
Preudent predator- no overexploitation
Defense Mech
25% insects- Phytophagous
Physical/Structural- Camouflage: Insects, Frogs
Morphological- Thorns: Acacia, Cactus
Chemical- Poison: Plants-inhibit digestion, disrupt reproduction; Calotropis: Poisonous cardiac glycosides
Competition --
Darwin
Potent force in organic evolution'
Process in which fitness (r) of 1 sps is lower than other
Unrelated sps: S American lakes - Flamingoes & fishes - zpk
Interfence competition: Feeding eff dec due to other's presence
Gause
Elimination of inf sps
Abingdon tortoise-Galapogos island- 1 decade
Gretaer browsing eff of goats
Competitive release
Sps restr to small area due to sup. sps
Connell's elegant field exp
Balanus sup. Chathamalus
Scotland sea coasts
Plants, herbivores- more adv affected
Competitive exclusion principle
No 2 sps occupy the same niche
Mac Arthur
Co existance
Resource Partitioning- diff feeding habits
Amensalism -0
Ibex & weevils
Black walnut tree sheddings
Toxic for other plants
Mutualism ++
Die if separated
Lichens - Fungi & algae
Mycorrhizae- Fungi & higher plant roots
Rhizobium & Root nodules of legumes
Plant-Pollinator
Rewards
Pollen
Nectar
Oviposition place
Nourishment- dev. seeds
Cheaters- steal rewards
Coevolution
Ficus & Blastophaga
Ophyrus orchid and bees, bumblebees
Sexual deceit
Pseudocopulation
1 petal of flower as female insect
Commensalism +0
Orchid (epiphyte) on Mango
Barnacles on Whale back
Cattle egrets and grazing cattle
Bacteria in int feeding on undig food
Clown fish and sea anemone w/ stinging tentacles
Parasitism +-
Adaptations
Coevolution w/ specific host
Loss of unncecessary org
Presence of adhesive org
Loss of dig. sys
High reproductive capacity
Complex life cycle
Human liver fluke (trematode)- snail, fish
Facilitated by vectors
Smartparasites
Plasmodium, HIV- change antigens- no vax produced
Ectoparasites
Human lice
Ticks on dogs
Copepods on marine fishes
Cuscuta on hedge plants
Lost chlorophyll
Haustoria
Endoparasites
Extreme specialization
Complex
Simple morph,, anatomy
High repr. potential
Brood Parasitism
Egg resembles host egg
Cuckoo, Crow