Class Notes (1,000,000)
CA (610,000)
UTM (20,000)
Environment (1,000)
ENV100Y5 (900)
Lecture 18

ENV100Y5 Lecture Notes - Lecture 18: Sympatric Speciation, Population Ecology, Vulnerable Species


Department
Environment
Course Code
ENV100Y5
Professor
Barbara Murck
Lecture
18

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Populations+can+be+separated+in+many+ways
!"#$%&'%() *+,#-#./"#$%#/.$(0#.1-(02.$-#&'%().(1.)#+./"#$%#/.
3&/%#/'.+&4.'(.$-#&'#.)#+./"#$%#/.5.
!
Populations+become+isolated2.,&""#)/./(0#,(+.-#"-(67$'%8#94.
Sympatric+speciation =+populations+become+reproductively+isolated+within+the+
same+area
:%8#-/%1%$&'%().&)6.#;'%)$'%().
!
Life’s+diversity+results+from+numerous+speciation+events
@&""#)#6.#8#).A#1(-#.,70&)/./,(+#6.7"B.CCD.(1.&99.',%)>/.',&'.#;%/'#6.
,&8#.>()#.#;'%)$'B.
Extinction =+the+disappearance+of+a+species+from+Earth+
Most%species%are%extinct!%
E(0"#'%'%()2."&',(>#)/2."&--%$%6#/.
Most+extinction+from+interactions+with+other+species+
F&$G>-(7)6.#;'%)$'%().
H8#-&>#./,#91.9%1#.1(-./"#$%#/.*I.0%99%().4#&-/.
Mass+extinctions+J9('/.(1.6#&',.%)./,(-'.'%0#K due+to+environmental+change+J%1.%'.
$,&)>#/.8#-4.L7%$G94.M.,&-6.'(.&6&"'.M.#;'%)$'%()K
Some+species+are+more+vulnerable+to+extinction+than+others
Rapid+environmental+change+may+lead+to+extinction+
Ex.+Great+tit+
BUT+Some+species+are+resilient:
Vulnerable+species:
N)94.1(7)6.%).NO3.&-#&2./$&9#.().',#.&-#&.8&-%#/B
Endemic+species: species+with+a+small+geographic+distribution
P&G#/.%'.6%11%$79'.'(.,&8#.0&'#-%&9.'(.,&8#./#9#$'%().().
Small+populations?./0&99#-.',#.9#//.*lack+genetic+diversity
Specific+habitat+requirements+
Slow+growth+potential:+long+time+to+mature,+few+offspring,+etc.
Extinction+is+a+natural+process
Extinction+is+irreversible
Humans+profoundly+affect+rates+of+extinction
Mass+extinction
P(/'.1&0%9%&-.0&//.#;'%)$'%().*Q<.
Mass+extinction
Mass+extinction:+50+95%+of+all+life+gone+*M+,#).%'R/.$()/%6#-#6.&.0&//.
#;'%)$'%()
P(/'.1&0%9%&-.0&//.#;'%)$'%().*Q<.
Are+we+in+the+6th+mass+extinction?+
Levels+of+ecological+ organization
Population+ecology =+quantitative+dynamics+of+populations
Community+ecology =+interactions+among+species+
Ecosystem+ecology =+living+and+nonliving+components+of+systems
Habitat
Environment+in+which+organism+lives
Living/nonXliving+components+
Scale+depends+on+organism
S6#&.',&'.+,&'.(->&)%/0/.7/#.%/)R'.-&)6(0
Habitat+selection =+nonXrandom+use+of+available+ habitat
Human+activity+conflicts+with+this+process
Eg.+Fragmentation+X$()$#-)#6.+%',./"&$#.1(-.,&A%'&'/
Ecological+niche
F&/%$&994.4(7-.-(9#2.#8#-4.(->&)%/0.6(#/./(0#',%)>.6%11#-#)'.%).',#%-.
,&A%'&'
Niche =+an+organisms+use+of+resources+and+its+functional+role+in+a+community+
T,#).4(7.6()R'.,&8#.'(.'&G#.%)'(.&$$(7)'.A4.&)4.(',#-.(->&)%/0/
Fundamental+niche: optimal+conditions
O%$,#.%/.-&%)#6.%).+,#).(',#-/.U(A.
V)#'19%;.&)6.7)6#-+#&-.#;&0"9#W
Realized+niche: a+subset+of+fundamental+niche+due+to+species+interactions
MacArthur's+Warblers+ex
P(-#.879)#-&A9#.'(.#;'%)$'%().
!
Specialists =+narrow+niches+and+very+specific+requirements+
Generalists =+broad+niches+that+can+use+a+wide+array+of+habitats+and+resources
Population+Characteristics
Population+density =+the+number+of+individuals+within+a+population+per+unit+area
Population+Distribution+
Random+X1&99.'-##/
Uniform+X#8#)94.6%/'-%A7'#6
Clumped+X1%/,#/./+%00%)>.'(>#',#-
Spatial+arrangement+of+organisms+
Sex+ratio =+proportion+of+males+to+females+
Age+Structure =+the+relative+numbers+of+organisms+of+each+age+within+a+
population
Survivorship+curves
Type+I: More+deaths+at+older+ages+
Type+II: Equal+number+of+deaths+at+all+ages+
Type+III: More+deaths+at+young+ages
Chapter(4(*Part(2(
Sunday,+October+18,+2015
6:05+PM
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