Below is a list of scalar ODE's with multiple parameters in the book.

For each of them you can scale the unknown and/or time with one of the parameters and combine parameters

Do so to derive a new equation with fewer parameters.

If there's only one parameter left: describe and explain the bifurcation diagram for the new unknown and the remaining  parameter. 

If there are two parameters left: pick a value of one of them and do the bifurcation diagram for the new unknown and the then remaining  parameter.

Example 2.2.2 circuit equation for Q with V_0,R,C

Section 2.3 logistic equation for N with r and K

Exercise 2.2.13 (terminal velocity) equation for v with m,g,K

Exercise 2.3.2 (autocatalysis) equation for x with k-minus,k-plus (k and l to get rid of subscripts) and a

Exercise 2.3.3 (tumor growth) Gompertz' equation for N with a and b

Exercise 2.3.4 (Allee effect) equation for N with r,a,b

Exercise 2.3.6 (language death) equation for x with two P's (P and Q to get rid of subscripts)

Exercise 2.3.6 (nonlinear version) equation for x with s and a

Example 3.2.1 (not a model) equation for x with a and b

Section 3.3 (laser model) equation for n with G,N,k

Section 3.6 (1) equation for x with h and r (cusp example!)

Section 3.7 (insect outbreak) (1) equation for N with R,A,B,K

Exercise 3.2.5 (chemical kinetics) equation for x with two c's

Exercise 3.6.6 (fluid patterns) equation for A with tau,epsilon,g

Exercise 3.6.6 (fluid patterns) another equation for A with tau,epsilon,g,k 

Exercise 3.7.3 (fishery) equation for N with r,K,H

Exercise 3.7.4 (fishery, improved model) equation for N with r,K,H,A

Exercise 3.7.5 (zebra stripes) equation for g with s_0 and 4 k's

Exercise 3.7.5 is the SIR model of Kermack and McHendrick, write and equation dy/dx for y as function of x

Exercise 3.7.5 the SIR model, partially solve to derive equation for u with a and b 

Exercise 3.7.5 (hysteretic activation) equation for p with 4 greek letters,K,n

Exercise 3.7.8 (irreversible response) equation for A_p?