Evolution bar with dates in a Beamer presentation

Question

I would like to plot an arrow with some years to remark in my resume presentation.

For example, in a slide like this:

I would place this arrow:

between the last line and the footnote of the slide.

The dates and date marks will appear as the presentation advances with the current years to talk about are in opaque color (2002 and 2005 in this example), and the past years change to be semitransparent or in a lower color (e.g., 2000 and 2001).

Answer 1

It is rather straightforward to do something along these lines with the aobs (aka overlay-beamer-styles) library. And sorry for not typing in your text, I am not good at Spanish.

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{overlay-beamer-styles}
 \tikzset{
    unhighlight on/.style={alt={#1{fill=gray!30!white,color=gray!30!white}{fill=red!80!black,color=red!80!black}}},
}
\begin{document}
\begin{frame}[t]
\frametitle{A time line}
\begin{tikzpicture}
\draw[line width=2mm,-latex,red!20] (-0.2,0) -- (9,0);
\foreach \X [evaluate=\X as \Y using int(\X-2000),count=\Z] in {2000,2001,2002,2005}
{\pgfmathtruncatemacro{\W}{\Z+1}
\draw[unhighlight on=<\W->] ({\Y-0.2},-0.5) -- ({\Y+0.2},-0.5) -- (\Y,-0.1) -- cycle;
\node[anchor=south,unhighlight on=<\W->,fill=white] at (\Y,0.2) {\X};}
\end{tikzpicture}
\begin{itemize}
\item Novemeber 2000: marmots start hibernating
\pause
\item Semptember 2001: \dots
\pause
\item July 2002: \dots
\pause
\item May 2005: marmots awake from hibernation
\end{itemize}
\end{frame}
\end{document}

As for the additional request:

\documentclass{beamer}
\setbeamercovered{transparent}
\usepackage{tikz}
\usetikzlibrary{overlay-beamer-styles}
 \tikzset{
    unhighlight on/.style={alt={#1{fill=gray!30!white,color=gray!30!white}{fill=red!80!black,color=red!80!black}}},
}
\begin{document}
\begin{frame}[t]
\frametitle{A time line}
\begin{tikzpicture}
\draw[line width=2mm,-latex,red!20] (-0.2,0) -- (9,0);
\foreach \X [evaluate=\X as \Y using int(\X-2000),count=\Z] in {2000,2001,2002,2005}
{\pgfmathtruncatemacro{\W}{\Z+1}
\ifnum\Z=4
\draw[fill=red!80!black,color=red!80!black] ({\Y-0.2},-0.5) -- ({\Y+0.2},-0.5) -- (\Y,-0.1) -- cycle;
\node[anchor=south,color=red!80!black] at (\Y,0.2) {\X};
\else
\draw[unhighlight on=<\W->] ({\Y-0.2},-0.5) -- ({\Y+0.2},-0.5) -- (\Y,-0.1) -- cycle;
\node[anchor=south,unhighlight on=<\W->,fill=white] at (\Y,0.2) {\X};
\fi}
\end{tikzpicture}
\begin{itemize}
\item<1> November 2000: marmots start hibernating
\item<2> August 2001: marmots eat
\item<2> Semptember 2001: marmots eat
\item<3> July 2002: marmots eat
\item<4> May 2005: marmots awake from hibernation
\item<4> November 2005: marmots start hibernating again
\end{itemize}
\end{frame}
\end{document}

FINAL EDIT(I hope): As for your second additional request: that's much easier (and I would actually be surprised if this has not previously been done, but I admit I am now too lazy to google).

\documentclass{beamer}
\setbeamercovered{transparent}
\usepackage{tikz}
\usetikzlibrary{overlay-beamer-styles}
 \tikzset{
    highlight on/.style={alt={#1{fill=red!80!black,color=red!80!black}{fill=gray!30!white,color=gray!30!white}}},
}
\begin{document}
\begin{frame}[t]
\frametitle{A time line}
\begin{tikzpicture}
\draw[line width=2mm,-latex,red!20] (-0.2,0) -- (9,0);
\foreach \X [evaluate=\X as \Y using int(\X-2000),count=\Z] in {2000,2001,2002,2005}
{
\draw[highlight on=<\Z>] ({\Y-0.2},-0.5) -- ({\Y+0.2},-0.5) -- (\Y,-0.1) -- cycle;
\node[anchor=south,highlight on=<\Z>,fill=white] at (\Y,0.2) {\X};
}
\end{tikzpicture}
\begin{itemize}
\item<1> November 2000: marmots start hibernating
\item<2> August 2001: marmots eat
\item<2> Semptember 2001: marmots eat
\item<3> July 2002: marmots eat
\item<4> May 2005: marmots awake from hibernation
\item<4> November 2005: marmots start hibernating again
\end{itemize}
\end{frame}
\end{document}