Reproductive and Somatic Effort in Dogwoods

Week II Principles of Ecology BIOL 3060

Review • Life history

• An organism’s typical pattern of :• Growth & Survival• Reproduction

• Somatic effort• Growth/survival

• Reproductive effort• Phenotypic plasticity

• A single organism can have >1 phenotype

• Spigot Model•Reproduction only when somatic is topped-off

Age & Reproduction

• H1 With more energy on one size of a plant than the other, phenotypic plasticity allows greater reproduction to occur on that side.

• prediction: the sunny side of the tree has more flower buds than the shady side.

Hypothesis 1

Age & Reproduction

• H2 Trees with more total energy can invest more in reproduction.

• prediction: trees with more sun have more flower buds.

Hypothesis 2

Age & Reproduction

• H3 Delayed maturity and indeterminate growth cause older/larger trees to have greater reproduction.

• prediction: there is a significant positive correlation between the proportion of flower buds and the DBH of the tree.

Hypothesis 3

H1 prediction: % flower buds is greater on the sunny than shady side of roadside trees

T-TEST1 22 21 2

1 2

x xTs sn n

X1

AVG % flower buds on the sunny side

(roadside)

X2

AVG % flower buds on the shady side

(roadside)

Note: this is a one-tailed test, with 38 d.f.

H2 prediction: % flower buds is greater for trees in the sun than for

those in the shade

T-TEST1 22 21 2

1 2

x xTs sn n

X2

AVG % flower buds in understory

X1

AVG % flower buds on sunny side of roadside trees

Note: this is a one-tailed test, with 38 d.f.

Correlation

a) If there is NO difference between % flower buds in sunny and shady environments:

Correlation #1: % total flower buds on roadside and understory trees (y-

axis) vs DBH (x-axis)

b) If there IS a difference between % flower buds in sunny and shady environments:

Correlation #1: % total flower buds on roadside trees (y-axis) vs DBH (x-

axis)Correlation #2: % total

flower buds on understory trees (y-axis) vs DBH (x-

axis)

H3 prediction: % flower buds and tree age/size (DBH) are significantly positively correlated

Why do we have conditional analysis?

Hypothesis & Prediction 3H3 prediction: % flower buds and tree age-size

(DBH) are significantly positively correlated

What do you get?→ correlation coefficient: r

-positive/negative relationship-significance of relationship

CORRELATION ANALYSIS

If correlation (r) between mean % flower buds and DBH is positive, look up the

significance

Note: (n1-2) = d.f.

Roadside Trees Understory Trees (40)

Sunny-side (20) Shady-side (20)

Total Total Total

Tree DBHFlowe

rLea

f % FlrFlowe

r Leaf % FlrFlowe

rFlowe

r Tree DBH LeafFlowe

rFlowe

r1 5 11 9 55% 5 15 25% 16 40% 1 3 31 9 23%2 9 15 5 75% 10 10 50% 25 63% 2 8 25 15 38%3 9 14 6 70% 9 11 45% 23 58% 3 8 25 15 38%

etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc. etc.

18 13 18 2 90% 13 7 65% 31 78% 18 7 18 22 55%19 8 13 7 65% 19 1 95% 32 80% 19 7 23 17 43%20 10 17 3 85% 12 8 60% 29 73% 20 5 4 36 90%

Mean 7.95 12.70   64% 10.80   54% 23.50 0.59   6.15   19.10 48%

S.D. 3.69 3.41   17% 3.68   18% 5.49 0.14   2.08   6.92 18%