The second law of thermodynamics says, "No process is possible in which the sole result is the transfer of energy from a cooler to a hotter body." The confusion arises when the 2nd law is phrased in another equivalent way, "The entropy of a closed system cannot decrease." Theists like you thus misinterpret the 2nd law to say that things invariably progress from order to disorder.
But, I'll even let that one slide for now, because there is an even more glaring error in your logic. Let's go ahead and apply this idea about temperatures to biological structure. You still have the glaringly obvious problem that Earth is not a closed system! You're completely ignoring a 1,980,000,000,000,000,000,000,000,000,00... kg object with a surface temperature of approximately 5778 K (5505 °C, 9941 °F). Why do plants grow? The sun. What causes most weather events on the planet? The sun. For your premise to make sense, it would mean the planet would have to get zero energy from external sources. Anyone can simply walk outside to realize why that it completely absurd.