\begin{tikzpicture}[node distance=1cm]

% Left Side: Antifungal metabolites
% Bacteria
\draw[thick, fill=gray!20] (-2, 2.5) ellipse (1.2cm and 0.5cm);
\node at (-2, 3.2) {Antifungal metabolites};

% Arrows for antifungal metabolites
\foreach \x in {-2.5, -2, -1.5}
  \draw[thick, ->] (\x, 2) -- (\x, 1.2);

% Antifungal metabolites (triangles)
\foreach \x in {-2.5, -2, -1.5}
  \node[fill=red!80!black, regular polygon, regular polygon sides=3, draw, scale=0.7] at (\x, 1.2) {};

% Fungi (left)
\draw[thick, fill=gray!50] (-2, 0.5) circle (0.5cm);
\node at (-2, -0.2) {Fungi};

% Right Side: Nutrient Competition
% Bacteria
\draw[thick, fill=gray!20] (3, 2.5) ellipse (1.2cm and 0.5cm);
\node at (3, 3.2) {Competition for nutrients};

% Arrows for nutrients
\foreach \x in {2.5, 3, 3.5}
  \draw[thick, <-] (\x, 2) -- (\x, 1.2);

% Available nutrients (triangles)
\foreach \x in {2.5, 3, 3.5}
  \node[fill=green!80!black, regular polygon, regular polygon sides=3, draw, scale=0.7, rotate=180] at (\x, 1.2) {};

% Fungi (right)
\draw[thick, fill=gray!50] (3, 0.5) circle (0.5cm);
\node at (3, -0.2) {Fungi};

% Legends
% Bacteria legend
\draw[thick, fill=gray!20] (-5.5, -2) ellipse (0.8cm and 0.3cm);
\node[anchor=west] at (-5, -2) {Bacteria};

% Fungi legend
\draw[thick, fill=gray!50] (-5.5, -3) circle (0.3cm);
\node[anchor=west] at (-5, -3) {Fungi};

% Antifungal metabolites legend
\node[fill=red!80!black, regular polygon, regular polygon sides=3, draw, scale=0.7] at (-5.5, -4) {};
\node[anchor=west] at (-5, -4) {Antifungal metabolites};

% Available nutrients legend
\node[fill=green!80!black, regular polygon, regular polygon sides=3, draw, scale=0.7, rotate=180] at (-5.5, -5) {};
\node[anchor=west] at (-5, -5) {Available nutrients};

\end{tikzpicture}